JP3755466B2 - OD traffic volume determination device and method - Google Patents

Description

【００２４】
なお、本発明の実施は、路上通信装置を用いて車両の位置を検出する形態に限定されるものではないことを予め断っておく。例えば、車載装置にＧＰＳ(Global Positioning System)などの車両位置検出機能を持たせ、車載装置から、識別コードと車両検出位置の情報を地上装置に取り込み、地上装置において、後述するセンター装置Ａと同様の構成を備えることにより、各車両のＯＤ間走行経路を求めることも可能である。この場合、車載装置と地上装置との通信は、携帯電話、自動車電話、あるいは専用回線を用いて定期的にもしくは不定期に行うこととすればよい。
【００２５】
―道路網―
図３は、路上ビーコン、カメラ等が設置された道路網のエリア地図である。
この地図では、道路は、縦横複数本描かれ、交差点が存在する。交差点間の道路を１リンク単位としてとらえ、上り下りのリンクＬ１〜ＬＮ（図３ではＮ＝４８）を構成している。リンク同士の十字接続点が交差点ノードＮ１，Ｎ２，‥‥，Ｎ９となっている。
【００２６】
路上ビーコンは、各リンクから交差点に進入する位置に設置され、黒い▲印で表されている。なお、路上ビーコンは、図３では、各交差点に設置されたように描かれているが、実際には、設置されていない交差点も存在する。また、交差点に進入する位置以外にも設置されることがある。カメラは、一定範囲の道路を見下ろす形で随所に設置されている。
また、道路の途中から細街路がつながり、道路の途中に店舗や住宅の駐車場が存在している。この図３では、作図の都合上、一部の道路のみに細街路や駐車場を描いているが、実際には、ほとんどの道路に細街路がつながり、駐車場が存在している。
【００２７】
―センター装置―
図４は、センター装置Ａ内の機能ブロック図である。図４の円筒形は、それぞれの部位に所属するメモリを示している。
センター装置Ａは、路上ビーコンＢとの間の送受信信号を変換する入力変換部１、カメラの画像信号を変換する入力変換部２、旅行時間計測部８、最適経路トリー算出部９、路上ビーコンＢの車両感知信号に基づいて地点交通量を算出する交通量計測部３、交通量計測部３により算出された地点交通量に基づいてＯＤ交通量Ｑ2を推定するＯＤ交通量推定部６を有している。
【００２８】
また、路上ビーコンＢの送受信信号やカメラの画像信号に基づいて、車両の識別コード、通過時刻、車種、前回通過したビーコンのコード、前回ビーコンを通過した時点からの走行時間のデータを取得しメモリに蓄積するデータ集計部４、データ集計部４のメモリに蓄積されたデータを取り出して、そのデータ等に基づいてＯＤ間走行経路を求めるＯＤ走行経路演算部５、ＯＤ間走行経路を統計的に処理することによりＯＤ交通量Ｑ1を推定するＯＤ交通量推定部７を有している。
【００２９】
そして、両ＯＤ交通量Ｑ1，Ｑ2に基づいて、最終的なＯＤ交通量Ｑを決定するハイブリッド処理部１０を備えている。
センター装置Ａは、コンピュータ、メモリ、入出力装置等を備え、各処理部３〜１０の機能の全部又は一部は、前記メモリに記録されたプログラムをコンピュータが実行することにより実現される。
以下、旅行時間計測部８、最適経路トリー算出部９、交通量計測部３、ＯＤ走行経路演算部５、ＯＤ交通量推定部６、ＯＤ交通量推定部７、ハイブリッド処理部１０で行う各処理を、必要ならばフローチャートを用いて順に説明する。
【００３０】
―リンク旅行時間計測―
旅行時間計測部８は、次のようにしてリンク旅行時間を計測する。
地点交通量計測値ｑ、占有時間Ｏ、及び平均車長（一定値とする）Ｉを用いて、式Ｖ＝Ｉ・ｑ／Ｏにより車両の平均速度Ｖを計算し、これとリンクの長さＬを用いて、式Ｔ＝Ｌ／Ｖによりリンク旅行時間Ｔを計算する。
また、カメラの計測画像から車両のプレートナンバーをマッチングして車両を同定し、同一車両がリンクの端を通過した時刻とリンクの他の端を通過した時刻とから、リンクを走行するのに要した時間Ｔ′を求める。単位時間に通過した車両が複数であれば、各車両のリンク旅行時間Ｔ′の平均をとる。
【００３１】
そして、以上のようにして求めたリンク旅行時間Ｔ若しくはリンク旅行時間Ｔ′のいずれか、またはこれらの重み付き平均をとって、時間帯ごとのリンク旅行時間とする。なお、旅行時間の計測誤差を吸収するためにフィルター値を用いてもよい。また曜日、時間帯、天候等によってばらつきがあるので、過去の統計的な値を加味してもよい。
―最適経路トリー算出―
最適経路トリー算出部９は、次のようにして最適経路トリーを算出する。最適経路トリーとは、いずれかのリンクを出発リンクとし、エリア内のすべてのリンクに至る最適経路の集合のことである（特開平７−２４４７９８号公報参照）。出発リンクから他の特定のリンクに至る最適経路は１本しか存在しないから、最適経路トリーは、出発リンクからトリー状に広がっていき、先で再び交わることはない。
【００３２】
最適経路トリーを算出するには、旅行時間計測部により求められたリンク旅行時間を使うが、これ以外にリンク距離を用いてもよい。
最適経路トリー算出部は、エリア内のすべてのリンクを出発リンクとして最適経路トリーを算出する。したがって、エリア内のリンクがＮ本あれば、最適経路トリーはＮ枚求まる。
−交通量計測−
交通量計測部３は、入力変換部１から得られる、路上ビーコンＢの感知信号に基づいて地点交通量（単位時間（例えば５分間）あたりの車両の通過台数）を算出する。路上ビーコンＢはリンクごとに設置されているので、地点交通量もリンクごとに求められる。したがって、以下「リンク地点交通量」という。
【００３３】
さらに交通量計測部３は、占有時間Ｏ（単位時間（例えば５分間）内に、各車両ｋが車両感知器を横切った時間ｔkの総和Σｔk）を検知する。
−ＯＤ走行経路演算−
図５は、ＯＤ走行経路演算部５の行うＯＤ走行経路演算処理を説明するためのフローチャートである。
まず、データ集計部４のメモリに蓄積された所定日数分の車両の識別コード、通過時刻、車種、前回通過したビーコンのコード、前回ビーコンを通過した時点からの走行時間のデータ（表１）を取得する（ステップＷ１）。そして、このデータを識別コードごとにソートして、メモリに記憶する（ステップＷ２）。この情報を「基本情報」という。表２は、基本情報の一覧表である。表２によれば、例えば、識別コード“１３５７”の車載装置の情報が、ひとかたまりにまとめられている。
【００３４】
【表２】

【００３５】
次に、基本情報から同一車両識別コードのデータを取り出す（ステップＷ３）。この同一車両識別コードのデータに基づいて、通過ビーコン順に並べ替える（ステップＷ５）。これにより、通過したビーコンを通過順に特定できる。また、通過ビーコン間の走行時間を算出することができる。
最新の時点に通過した路上ビーコンが車両の消滅地点（Ｄ）を表し、最も早く通過し「前回通過したビーコンなし」のフラグが付されている路上ビーコンが車両の発生地点（Ｏ）を表す。
【００３６】
次に、通過ビーコン間の走行経路を求める（ステップＷ７）。路上ビーコンＢは、通常、図３に示すように、交差点ごとに設置されているので、通過ビーコン間の走行経路とは、交差点間を結ぶ道路となる。しかし、路上ビーコンＢが交差点ごとに設置されていない場合は、走行経路が一意的に定まらないので、公知のダイクストラ法、ポテンシャル法等に基づいて通過ビーコン間の最適経路を算出する（例えば特開平７−２４４７９８号公報参照）。最適経路を算出するには、リンク旅行時間又はリンク距離のいずれをベースとしてもよい。
【００３７】
実際に車両が算出された最適経路を走行したかどうか１００％確定できないが、最適経路を走行した可能性がもっとも高いので、車両は最適経路を走行したものとみなし、これを走行経路とする。
−ＯＤ間走行経路に基づくＯＤ交通量演算−
車載装置Ｃを搭載する各車両に対して、以上のＯＤ間走行経路を求めれば、ＯＤ交通量推定部７は、求められた各車両のＯＤ間走行経路を、地域別、時間帯別に分類し、各地域ごと、時間帯ごとに、各車両のＯＤ間走行経路に基づいて、ある地点から発生し、他の地点で消滅する、単位時間当たりの車両台数であるＯＤ交通量Ｑ1を算出する。
【００３８】
―交通量計測に基づくＯＤ交通量演算―
次に、交通量計測部３によって求められたリンク地点交通量を用いて、ＯＤ交通量Ｑ2を算出する方法を説明する。［発明が解決しようとする課題］で述べたように種々の手法が採用されるが、この［発明の実施の形態］では、同じ出願人の特許出願，特願平2000−233430号に記載したＯＤ交通量演算方法を説明する。この方法によれば、出発リンクに一定の交通量を設定し、経路トリーに沿って、経路トリーの分岐部で交通量を分配し、リンクで交通量を一部消滅させながらシミュレート走行させることにより、各リンクにおける通過交通量を求める。エリア内の各リンクを出発リンクに選ぶことによりそれぞれ求めた通過交通量から、リンクの地点交通量とリンク発生交通量とを結びつける通過確率行列を求め、この通過確率行列と、リンクで計測した地点交通量計測値とに基づいて、リンク発生交通量を算出することができる。
【００３９】
そして、各リンクを出発リンクとして探索した経路トリーに沿って、前記リンク発生交通量を、経路トリーの分岐部で分配し、リンクで交通量を一部消滅させながらシミュレート走行させることにより、ＯＤ交通量を推定する。
−通過確率行列Ｈの算出−
ＯＤ交通量推定部６の行う通過確率行列Ｈの算出方法を説明する。
図６は、通過確率行列Ｈの算出方法を説明するためのフローチャートである。
【００４０】
まず、ＯＤ交通量推定部６は、交通量計測部３から、車両感知器の感知信号に基づいて得られたリンク地点交通量計測値を取得する(ステップＸ１)。このリンク地点交通量計測値はリンクの数Ｎだけあるので、Ｎ次元ベクトルとして扱える。
次に、リンク発生交通量設定値、リンク消滅交通量設定値を算出する(ステップＸ２)。
【００４１】
図３に示したように、通常、車両感知器は１本のリンクあたり１台設置されていて、リンクの終点にも起点にも設置されている、ということは少ない。
そこで、図７に示すように、あるノード（例えばＮ５とする）と、当該ノードＮ５に流入するリンクＬ１２，Ｌ２５，Ｌ２７，Ｌ３０と、ノードから流出するリンクＬ１１，Ｌ２６，Ｌ２８，Ｌ２９とを１つの領域とし、単位時間に、この領域に発生する領域発生交通量又は消滅する領域消滅交通量Ｊを考える。領域発生交通量又は領域消滅交通量Ｊは、図７の例に従えば、４本のリンクＬ１１，Ｌ２６，Ｌ２８，Ｌ２９を通して流出する交通量Ｑoutから、４本のリンクＬ１２，Ｌ２５，Ｌ２７，Ｌ３０を通して流入する交通量Ｑinを引いたものである。Ｊが正の場合は、領域発生交通量Ｊ＞０，領域消滅交通量＝０とし、負の場合は、領域消滅交通量｜Ｊ｜＞０，領域発生交通量＝０とする。
【００４２】
そしてこの領域発生交通量を流出するリンク本数で割った値を、「リンク発生交通量設定値」といい、領域消滅交通量を流出するリンク本数で割った値を、「リンク消滅交通量設定値」という。流出するリンク本数が４本であれば、リンク発生交通量設定値は、領域発生交通量の４分の１となり、リンク消滅交通量設定値は、領域消滅交通量の４分の１となる。
図８は、リンク発生交通量設定値又はリンク消滅交通量設定値を説明するためのリンク図であり、図８(a)は領域発生交通量Ｊ＞０の場合に、リンク発生交通量設定値がＪ／４、リンク消滅交通量設定値は０となることを示し、図８(b)は領域消滅交通量Ｊ＞０の場合に、リンク消滅交通量設定値がＪ／４、リンク発生交通量設定値は０となることを示している。
【００４３】
また、領域発生交通量、領域消滅交通量をともに「流出」リンク本数で割ったのは、他のノードでの処理結果とリンクの重複を回避するためである。勿論、領域発生交通量、領域消滅交通量をともに「流入」リンク本数で割ってもよい。
リンク本数で割るので粗い近似になるが、後に説明するような数学手法を用いることにより、精度よく「リンク発生交通量」を算出することができる。
また、精度にこだわらなければ、リンク発生交通量設定値をそのまま「リンク発生交通量」とすることもできる。
【００４４】
次に、最適経路トリー算出部５から、エリア内のあるリンクを出発リンクとする最適経路トリーを取得する(ステップＸ３)。
そして、一定の交通量を、最適経路トリーに沿ってシミュレート走行させる(ステップＸ４)。
以上のステップＸ３，Ｘ４の処理を、出発リンクを変えて、繰り返し行う(ステップＸ５)。
【００４５】
これらの走行結果に基づき、通過確率行列を算出する(ステップＸ６)。
以下、ステップＸ４〜Ｘ６の内容を詳説する。
一定の大きさの交通量を、最適経路トリーに沿ってシミュレート走行させる場合、最適経路トリーのそれぞれのノードで、交通量は所定割合で各リンクに分配され、分配後所定割合で消滅する。そして、消滅後の各リンクに残った交通量（これを「リンク通過交通量」という）が、次のノードで再度分配され、所定割合消滅するという動作を繰り返す、と考える。
【００４６】
出発リンクの交通量を１とすると、前記通過交通量は、当然１より小さい値をとる。通過交通量は、リンクの数だけ求まるので、Ｎ次元ベクトルで記述できる。これを以下「通過交通量ベクトル」という。
交通量を分配する方法として、次の３つの方法ａ１，方法ａ２、方法ａ３が考えられる。
方法ａ１：ノードの先の各リンクよりつながる部分的な経路トリーを１まとめに考え（これを「経路ブロック」という）、経路ブロックを構成するリンクのリンク消滅交通量設定値の総和を求め、この総和に比例した割合で、分配される、とする方法である。
【００４７】
図９は、図３の道路地図に対応する経路トリーの一例を示す図であり、出発リンクをリンクＬ１にとっている。リンクＬ１から先のリンクは、Ｌ３，Ｌ６，Ｌ７である。リンクＬ３の先のリンクはこのエリアでは存在せず、経路ブロックＢ１の構成リンクはＬ３のみである。リンクＬ６の先のリンクＬ２２，Ｌ２５，Ｌ２４，‥‥を含む経路ブロックをＢ２で示し、リンクＬ７の先のリンクＬ９，Ｌ１２，Ｌ１３，‥‥を含む経路ブロックをＢ３で示している。
【００４８】
経路ブロックを構成する各リンクについて、リンク消滅交通量設定値の和ＪＢiを求める。経路ブロックＢ１については、ＪＢ1は、リンクＬ３のリンク消滅交通量設定値となる。経路ブロックＢ２については、ＪＢ2は、リンクＬ６，Ｌ２２，Ｌ２５，Ｌ２４，‥‥のリンク消滅交通量設定値の和となる。経路ブロックを構成する各リンクのリンク発生交通量設定値を考慮しないのは、各経路トリーの出発リンクで、リンク発生交通量が考慮されているからである(ステップＸ３，Ｘ５)。
【００４９】
方法ａ２：経路ブロックを構成する各リンクの、リンク地点交通量計測値×リンク距離の総和を求め、この総和に比例した割合で、分配される、とする方法である。
方法ａ３：交差点における直進右左折の比率を利用する。この直進右左折の比率は、車両感知器やカメラの情報に基づいて、各車両の走行経路を蓄積すれば、統計的に求めることができる。勿論、曜日、時間帯、天候等によって有意差があれば、これらの条件を加味してもよい。
【００５０】
交通量をリンクにおいて消滅させる方法として、次の２つの方法ｂ１，方法ｂ２が考えられる。
方法ｂ１：当該リンクのリンク消滅交通量設定値を用いて、割合
（リンク消滅交通量設定値）／（リンク地点交通量計測値）
で消滅していくとする方法である。
方法ｂ２：走行距離に従って、ある確率で消滅していくとする方法である。
【００５１】
道路網に発生した車両は、走行していくと、走行距離に応じてある確率分布をもって消滅していく。この確率分布をＰ（ｕ）（ｕは走行距離）と書くと、車両が距離ｕ走行するまでに消滅する確率は、
【００５２】
【数１】

【００５３】
で表される。Ｐ（∞）＝１である。
従って、出発リンクから最適経路トリーを走行して、ｎ本目の当該リンクを通過した地点で消滅する確率Ｐnから、当該リンクに入る前に（ｎ−１）本目で消滅している確率Ｐn-1を引けば、当該リンクで消滅する確率を求めることができる。
前記確率分布Ｆ（ｔ）の形は、多数の車両の走行データから数値的に求めることが好ましいが、この実施形態では、簡単のため、平均距離ｍ，分散σの正規分布と仮定しておく（実際の分布も正規分布に近い形になると考えている）。
【００５４】
【数２】

【００５５】
以上のように、一定の交通量を、最適経路トリーに沿ってシミュレート走行させ、通過交通量ベクトルを求め、出発リンクを変えて、同様の処理を行い、通過交通量ベクトルを求める。すべての出発リンクについて終了すれば、Ｎとおりの通過交通量ベクトルが求まるので、これを行列形式で書くことができる。この行列を「通過確率行列」Ｈということにする。
−リンク発生交通量の算出−
次に、リンク発生交通量ｘを算出する。リンク発生交通量ｘは、「単位時間内に、リンクの終点から流出する交通量から、当該リンクの始点に流入する交通量を引いたもの」と定義される。つまりリンクの途中で細街路に入ったり、細街路から現れたり、駐車場に入ったり駐車場から出たりする交通量の差し引き、と理解できる。このリンク発生交通量ｘもリンクの数Ｎだけあるので、Ｎ次元ベクトルとして扱える。
【００５６】
リンク発生交通量ｘとリンク地点交通量計測値ｑとの関係は、通過確率行列を使って、
ｑ＝Ｈｘ (2)
ｘ＝Ｈ^-1ｑ
となる。したがって、リンク地点交通量計測値に基づいて、通過確率行列を使ってリンク発生交通量ｘを算出することができる。
【００５７】
以上の処理で、通過確率行列Ｈは、交通量を分配する方法として方法ａ１，方法ａ２又は、方法ａ３を用い、交通量を消滅させる方法として、方法ｂ１又は方法ｂ２を用いて算出した。しかし、これらの方法は、近似的な方法であり、実際にはリンク地点交通量計測値ｑは誤差を含む。その誤差をηと書くと、(2)式は、
ｑ＝Ｈｘ＋η (3)
となる。
【００５８】
式(3)について、リンク発生交通量ｘの分散及び誤差ηの分散がわかっている場合には、ベイズの推定を用いて正確なリンク発生交通量ｘを推定することができる。
リンク発生交通量設定値ａ、リンク発生交通量ｘの分散Σ、誤差ηの分散Ｒを下記のように表す。
a = E(x) a：リンク発生交通量設定値
Σ= cov(x) Σ：リンク発生交通量ｘの分散
R= cov(η) R：誤差ηの分散
ベイズの推定を用いて、リンク発生交通量ｘを推定することができる。
【００５９】
Γ^-1 =Σ^-1 + H'R^-1H H'：Hの転置行列
ｘ＝Γ(H'R^-1q +Σ^-1a)
一方、リンク発生交通量ｘに制約条件がある場合、例えば、リンク発生交通量ｘの上下限値（ただし交通容量以下）が設定してある場合には、式(3)が極力成立するように、２次計画法を用いてリンク発生交通量ｘを推定することができる。
【００６０】
Σ｜η_i｜が最小値となるようにリンク発生交通量ｘを推定する。すなわち、(Hx−q)'(Hx−q) の最小値を求めることにより、リンク発生交通量ｘが求まる。
ただし、制約条件は、０≦ｘ_i≦Ｘ_i （Ｘ_iはｘiの上限値）
(Hx−q)'(Hx−q)= (1／2)x'(2H'H)x + (−2H'q)'x + q'q
= (1／2)x'Gx + C'x + q'q G：正定値の対称行列
である。
【００６１】
−ＯＤ交通量Ｑ2の推定−
図１０は、ＯＤ交通量Ｑ2の推定方法を説明するためのフローチャートである。
まず、ＯＤ交通量推定部６は、一定時間ごとに、リンク地点交通量計測値ｑを取得し(ステップＹ１)、前述したようにリンク発生交通量を算出する(ステップＹ２)。各リンクを出発リンクとして最適経路トリーを求める(ステップＹ３)。
【００６２】
出発リンクごとに、一定時間分のリンク発生交通量を、最適経路トリーに従って走行させ、トリーの分岐部では交通量を分配させ、リンク部では消滅交通量を生じさせて交通をトリー末端に向けて流してゆく(ステップＹ４)。交通量が全て消滅したところで処理を終了する。
その結果、発生した車両のうち所定割合の車両について、各リンクの通過時刻および消滅時刻などを統計的に把握することができる(ステップＹ５)。
【００６３】
この結果、ＯＤ交通量Ｑ2を推定することができる。次の表３は、発生車両について、各リンクの通過時刻および消滅時刻などを把握したテーブルの例である。
【００６４】
【表３】

【００６５】
―ハイブリッド処理―
次に、ＯＤ交通量Ｑ1，Ｑ2の重み付き平均をとるためのハイブリッド処理を説明する。
図１１は、ハイブリッド処理の流れを説明するためのフローチャートである。
いままでの処理で求められたＯＤ交通量Ｑ1，Ｑ2は、リンクごとに規定されたものである。このため、車両台数の絶対数が少なく、これに基づいて処理をすると誤差が多くなるおそれがある。そこで、ＯＤ交通量Ｑ1，Ｑ2をそれぞれ地域ごとにまとめる（ステップＺ１，Ｚ２）。
【００６６】
図１２は、地域ごとにまとめる方法を解説するための図である。
図１２(a)はリンクごとのＯＤ交通量を示す表であり、リンクＬi(i=1,2,..)から発生しリンクＬj(j=1,2,..)で消滅する単位時間あたりの台数を記載している。
図１２(b)は地域単位でまとめられたＯＤ交通量を示す表である。地域Ｒi(i=1,2,..)から発生し地域Ｒj(j=1,2,..)で消滅する単位時間あたりの台数を記載している。それぞれの地域に、一又は複数のリンクが対応する。ある地域のＯＤ交通量は、その地域内の、一又は複数のリンクのＯＤ交通量の和となる。
【００６７】
例えば、ある地域Ｒ1がリンクＬ1，Ｌ2からなり、ある地域Ｒ2がリンクＬ3，Ｌ4からなるとする。リンクＬ1から発生しリンクＬ3で消滅するＯＤ交通量Ｑ2をａ、リンクＬ1から発生しリンクＬ4で消滅するＯＤ交通量Ｑ2をｂ、リンクＬ2から発生しリンクＬ3で消滅するＯＤ交通量Ｑ2をｃ、リンクＬ2から発生しリンクＬ4で消滅するＯＤ交通量Ｑ2をｄとする。
地域Ｒ1で発生し、地域Ｒ2で消滅するＯＤ交通量Ｑ2は、ａ＋ｂ＋ｃ＋ｄとなる。
【００６８】
次に、ＯＤ交通量Ｑ1について、車載装置の搭載率を考慮した拡大処理を施す（ステップＺ３）。すなわち、車載装置を搭載する車両のＯＤ交通量に、車載装置を搭載する車両と全車両との比率の逆数をかけて、全車両のＯＤ交通量を求める。なお、前記「搭載率」は、年月日、時間帯、地域などの関数となる。
あるいは、広域ΣＲi(iはＯＤ交通量を決定する対象となる全ての地域にわたる)における、ＯＤ交通量Ｑ1の合計とＯＤ交通量Ｑ2の合計との比を用いて、搭載率を推定してもよい。広域とは、日本全国でもよく、都道府県でもよい。前記広い地域において、搭載率φを、次の式により求める。
【００６９】
φ＝（広域におけるＯＤ交通量Ｑ1の合計）／（広域におけるＯＤ交通量Ｑ2の合計）
当該地域Ｒiの車載装置搭載車両のＯＤ交通量Ｑ1に、この搭載率の逆数１／φをかけて、当該地域Ｒiの全車両のＯＤ交通量Ｑ1を求めることができる。
そして、ＯＤ交通量Ｑ1（拡大後のもの）及びＯＤ交通量Ｑ2の重み付け平均をとってＯＤ交通量Ｑを求める（ステップＺ４）。式で示せば、
ＯＤ交通量Ｑ＝α（拡大後のＯＤ交通量Ｑ1）＋（１−α）（ＯＤ交通量Ｑ2）
となる。αは当該地域Ｒiごとの重み係数（０≦α≦１）である。
【００７０】
そして、ＯＤ交通量Ｑをリンク単位のものに換算する（ステップＺ５）。すなわち、地域のＯＤ交通量を、その地域に含まれる一又は複数のリンクのＯＤ交通量に分散させる。この換算は、ステップＺ２で行ったＯＤ交通量Ｑ2を地域ごとにまとめた処理の逆算を行えばできる。
例えば、地域Ｒ1で発生し、地域Ｒ2で消滅するＯＤ交通量Ｑ2から、リンクＬ1から発生しリンクＬ3で消滅するＯＤ交通量を逆算で求めるには、ａ／（ａ＋ｂ＋ｃ＋ｄ）をかければよい。
【００７１】
なお、ステップＺ１で行った処理の逆算を行うことも考えられるが、ＯＤ交通量Ｑ1は、車載装置の搭載率がかかっているので、車両台数の絶対数が特に少なく（例えば、リンク単位のＯＤ交通量Ｑ1の中には、ａ＝０といった値を示すものがある）、この値で逆算をすると、誤差が多くなるおそれがあるので好ましいとはいえない。
ＯＤ交通量をリンク単位のものに換算した後、ある発生地点Ｏから消滅地点Ｄまでの最適経路を算出してこれを走行経路とみなし、交通量をシミュレート走行させる。そして、この処理を全発生地点Ｏ及び全消滅地点Ｄについて行う（ステップＺ６）。これにより、各リンクの通過交通量を算出することができる。
【００７２】
次に、この算出された各リンクの通過交通量を、リンクの地点交通量計測と比較する（ステップＺ７）。比較の結果、各リンクにおける差がなく、あるいは比ｒが１となればよいが、そうでなければ（ステップＺ８のＮＯ）、各リンクにおいて、差ができるだけ０に近くなるように、あるいは比ｒができるだけ１に近くなるように、前記重み係数αを変更して（ステップＺ９）、ステップＺ４に戻り、前述した処理を繰り返す。
【００７３】
差の絶対値がしきい値より小さくなり、あるいは比ｒと１との差の絶対値｜ｒ−１｜がしきい値よりも小さくなれば、当該ＯＤ交通量Ｑを出力する（ステップＺ８のＹＥＳ）。前記しきい値は、多数のモデルについて本発明のＯＤ交通量決定処理を行って検証し、適切な値に設定することが好ましい。
以上の処理により、車両のＯＤ間走行経路を直接計測して求めたＯＤ交通量Ｑ1と、地点交通量の測定データから間接的に推定したＯＤ交通量Ｑ2とを用いて、より精度のよいＯＤ交通量Ｑを求めることができる。
【００７４】
以上のＯＤ交通量Ｑを用いれば、リンクごとに、各時間帯の交通量を予測することができ、交通量予測や交通量制御に役立てることができる。
なお、図１１を用いた説明では、地域ごとにまとめる処理ステップＺ１，ステップＺ２、及びリンク単位に換算する処理ステップＺ５を行っていたが、これらの処理を省いて、すべてリンク単位で処理を行ってもよい。
−ＯＤ交通量Ｑ1のみに基づく処理−
次に、厳密にはハイブリッド処理とはいえないが、ＯＤ交通量Ｑ1のみからＯＤ交通量Ｑを求める処理を説明する。これは、ステップＺ４の平均演算において、常にα＝１とし、車載率の逆数に相当する係数（ステップＺ３）をより正確に求める場合に相当する。
【００７５】
図１３は、ＯＤ交通量Ｑ1のみの処理を説明するためのフローチャートである。
まず、ＯＤ交通量Ｑ1に、係数をかける拡大処理を施す（ステップＺ１１）。係数はリンクごとに設定してもよく、地域ごとに設定してもよい。
次に、図１１と同様、ある発生地点Ｏから消滅地点Ｄまでの最適経路を算出してこれを走行経路とみなし、交通量をシミュレート走行させる。そして、この処理を全発生地点Ｏ及び全消滅地点Ｄについて行う（ステップＺ１２）。これにより、各リンクの通過交通量を算出することができる。
【００７６】
次に、この算出された各リンクの通過交通量を、リンクの地点交通量計測と比較する（ステップＺ１３）。比較の結果、各リンクの差がなく、あるいは比ｒが１となればよいが、そうでなければ（ステップＺ１４のＮＯ）、各リンクについて、差ができるだけ０に近くなるように、あるいは比ｒができるだけ１に近くなるように、前記係数を変更して（ステップＺ１５）、ステップＺ１１に戻り、前述した処理を繰り返す。
【００７７】
差の絶対値がしきい値より小さくなり、あるいは比ｒと１との差の絶対値｜ｒ−１｜がしきい値よりも小さくなれば、当該ＯＤ交通量Ｑを出力する（ステップＺ１４のＹＥＳ）。
これにより、ＯＤ交通量Ｑ1のみから、正確なＯＤ交通量Ｑを求めることができる。
【００７８】
【発明の効果】
以上のように本発明のＯＤ交通量決定装置又は方法によれば、ＯＤ間交通量を良好な精度で求めることができる。したがって、精度のよいＯＤ交通量に基づいて、交通量予測や交通量制御に役立てることができる。
【図面の簡単な説明】
【図１】路上ビーコンＢの配置図である。
【図２】路上ビーコンＢからセンター装置にデータを送信する手順を説明するためのフローチャートである。
【図３】路上ビーコンＢ、カメラ等が設置された道路網のエリア地図である。
【図４】センター装置の機能ブロック図である。
【図５】ＯＤ走行経路演算部５の行うＯＤ走行経路演算処理を説明するためのフローチャートである。
【図６】通過確率行列Ｈの算出方法を説明するためのフローチャートである。
【図７】領域発生交通量又は領域消滅交通量を説明するための交差点リンク図である。
【図８】リンク発生交通量設定値又はリンク消滅交通量設定値を説明するためのリンク図である。
【図９】図３の道路地図に対応する経路トリーの一例を示すリンク図である。
【図１０】ＯＤ交通量推定方法を説明するためのフローチャートである。
【図１１】ハイブリッド処理の流れを説明するためのフローチャートである。
【図１２】ＯＤ交通量を地域ごとにまとめる方法を解説するための図である。
【図１３】ＯＤ交通量Ｑ1を車載装置の搭載率を考慮して拡大し、その精度を上げる処理を説明するためのフローチャートである。
【符号の説明】
１ 入力変換部
２ 入力変換部
３ 交通量計測部
４ データ集計部
５ ＯＤ走行経路演算部
６ ＯＤ交通量（Ｑ2）推定部
７ ＯＤ交通量（Ｑ1）推定部
８ 旅行時間計測部
９ 最適経路トリー算出部
１０ ハイブリッド処理部
Ａ センター装置
Ｂ 路上ビーコン
Ｂ１ 投受光器
Ｂ２ 制御装置
Ｃ 車載装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an OD traffic volume determined based on communication between an in-vehicle device (including both a device installed in a vehicle and a device brought into the vehicle) that transmits an identification code, and a ground device, The present invention relates to an OD traffic volume determination apparatus and method for determining a more accurate OD traffic volume using an OD traffic volume obtained by volume measurement.
[0002]
[Prior art]
OD traffic is also referred to as origin / endpoint traffic, and refers to the number of vehicles per unit time that originates from a point with a certain scale of road network and disappears at other points ([1] Ryuichi Mato et al. Volume measurement system "Matsushita Technical Journal Vol. 44 No. 3 Jun. 1998).
The “occurrence” means a case where a vehicle enters the road network of a certain scale from a road network (narrow street) or a parking lot of a smaller scale, and the “disappearance” means a road of the certain scale. This refers to the case where a vehicle exits from the net to the narrow street or parking lot.
[0003]
Moreover, focusing on one vehicle, starting from a certain point, passing through a certain route, and disappearing at another point is called “trip”. This tripped route is referred to as “inter-OD travel route”.
On the other hand, the number of vehicles per unit time passing through a certain point is referred to as point traffic or observed traffic.
The OD traffic volume is an important parameter useful for studying and evaluating traffic volume prediction and various traffic controls because the traffic volume can be expressed more precisely than the point traffic volume.
[0004]
In order to know the OD traffic volume, there are a method of directly measuring the travel route between ODs and a method of indirectly estimating from the measurement data of the point traffic volume.
[0005]
[Problems to be solved by the invention]
The method of directly measuring the travel route between ODs is a method in which a road communication device such as an optical beacon is installed on the road, and the vehicle is tracked by bidirectional communication with the in-vehicle device.
The weak point of this method is that data for all vehicles cannot be obtained because the number of vehicles equipped with in-vehicle devices is limited. Therefore, to obtain the OD traffic volume, the number of vehicles must be corrected by multiplying the reciprocal of the ratio of the number of vehicles equipped with in-vehicle devices and the total number of vehicles traveling. However, there is no guarantee that this correction is always accurate. Absent.
[0006]
On the other hand, several theoretical methods have been proposed as a method for indirectly estimating from the measured traffic volume data (see [2] [3] [4]).
[2] Koichi Sakai, Shinji Tanaka, Ikuo Yoshii, Masao Kuwabara: “Examination of OD estimation accuracy based on the metropolitan expressway traffic origin and destination survey” Traffic Engineering, Vol. 33, No.6 (1998)
[3] Yasuo Yoshii, Masao Kuwahara, Hirokazu Akabane, Ryota Horiguchi: "Estimation of dynamic OD traffic volume from roadside traffic volume using traffic simulation" Civil Engineering Planning Research Papers No. 15 (1998)
[4] Hiroyuki Koneyama, Masao Kuwabara: “Estimation of OD traffic over time from roadside observed traffic”, Traffic Engineering, Vol. 32, No.2 (1997)
In addition, invented by the present inventor, in order to estimate the OD traffic volume efficiently and accurately, the traffic volume generated for each road section (link) is distributed to the links in each direction according to the shortest route tree. There is also a method using a model that disappears (Japanese Patent Application No. 2000-233430).
[0007]
However, each of the above estimation methods for OD traffic is only indirectly estimated from the measurement data of the point traffic, and the estimated OD traffic is the actual OD traffic. It is necessary to verify whether or not.
Therefore, the object of the present invention is to compensate for the drawbacks of the OD traffic volume obtained by directly measuring the OD travel route of the vehicle and the OD traffic volume indirectly estimated from the measurement data of the point traffic volume, Accordingly, an object of the present invention is to provide an OD traffic determination device and method that can accurately reproduce the actual OD traffic.
[0008]
[Means for Solving the Problems]
(1) The OD traffic volume determination device of the present invention includes an average calculation means for performing a weighted average calculation of the OD traffic volume Q1 and the OD traffic volume Q2, and an annihilation point (D) from the generation point (O) of the OD traffic volume. The optimal route calculation means for calculating the optimal route up to and the weighted averaged OD traffic from the point of occurrence (O) to the point of disappearance (D) along the optimal route, Measured by the point traffic volume calculating means for calculating the traffic volume, the spot traffic volume measuring means for measuring the spot traffic volume at each point, the spot traffic volume calculated by the spot traffic volume calculating means, and the spot traffic volume measuring means. Weight coefficient determining means for determining a weighting coefficient when performing the average calculation so that the traffic volume at the point is equal to or less than a predetermined error, and the average calculation means is based on the determined weighting coefficient. OD traffic volume Q1 and OD traffic volume Q2 Determine the OD traffic volume Q and the weighted average calculation, and outputs the OD traffic volume Q (claim 1).
[0009]
According to the OD traffic volume determination device of this configuration, the weighted average calculation of the OD traffic volume Q1 and the OD traffic volume Q2 is performed, and the weighted averaged OD traffic volume is calculated from the generation point (O) to the disappearance point ( D) Travel along the optimal route (shortest distance route, shortest time route, etc.) to calculate the point traffic volume at each point, and the calculated point traffic volume and the point traffic measured at each point A weighting factor for the average calculation is determined so that the amount matches with a predetermined error or less, and a weighted average of the OD traffic Q1 and the OD traffic Q2 is determined based on the determined weighting factor. OD traffic volume Q is calculated and output.
[0010]
Thus, since the weighting factor can be finally determined so that the OD traffic volume Q matches the spot traffic volume measured at each point, the OD traffic route of the vehicle is directly measured and obtained. It is possible to obtain the OD traffic volume Q with higher accuracy than both the OD traffic volume Q1 and the OD traffic volume Q2 indirectly estimated from the measurement data of the point traffic volume. The OD traffic volume Q1 obtained based on the communication between the in-vehicle device and the ground device is further provided with an OD traffic volume expanding means for correcting the OD traffic volume Q1 in consideration of the mounting rate of the in-vehicle device. It is preferable to perform a weighted average calculation of the expanded OD traffic volume Q1 and the OD traffic volume Q2 (claim 2). The mounting rate of in-vehicle devices is low at present, and if processing is performed without taking this mounting rate into consideration, the OD traffic volume Q1 will be evaluated lower than the actual one, and it will not be possible to obtain a highly accurate OD traffic volume Q. Because it ends up.
[0011]
The mounting rate of the in-vehicle device may be determined by obtaining a ratio between the OD traffic volume Q1 and the OD traffic volume Q2 over a wider area than the area where the OD traffic volume Q is to be determined (Claim 3). . The ratio of OD traffic volume Q1 and OD traffic volume Q2 is calculated over a wide area to estimate the on-board device installation rate. This is an effective method when data on the mounting rate of the in-vehicle device cannot be obtained.
The OD traffic volume Q1 obtained based on the communication between the in-vehicle device and the ground device and the OD traffic volume Q2 obtained by traffic measurement are converted from the OD traffic volume in the link unit to the OD traffic volume in the region unit. Conversion means, and inverse conversion means for inversely converting the OD traffic volume in the region unit to the OD traffic amount in the link unit, wherein the average calculation processing is performed based on the OD traffic volume in the region unit, and the point traffic The process of calculating the point traffic volume of each point by the volume calculation means can be performed based on the reversely converted OD traffic volume of the link unit (claim 4). The OD traffic volume Q1 obtained based on the communication between the in-vehicle device and the ground device and the OD traffic volume Q2 obtained by the traffic volume measurement each include an error. Since the error is averaged, it is easier to process than Therefore, the OD traffic volume is converted into the regional unit. However, since the process of calculating the point traffic volume at each point can be performed only in units of links, in this case, reverse conversion is performed in units of links.
[0012]
Even when the OD traffic volume Q1 is increased, it is preferable that the OD traffic volume Q1 is increased based on the OD traffic volume in each region. When expressed in link units, the error of the OD traffic volume Q1 is large when the on-board device mounting rate is low. For example, although the vehicle is generated, the OD traffic volume Q1 may become 0. In this case, even if it is enlarged, it is 0, so that it does not match the actual situation. Therefore, it is preferable to use OD traffic volume on a regional basis.
[0013]
Preferably, the inverse conversion means performs an inverse conversion using an inverse number of a conversion coefficient used when converting the OD traffic volume Q2 from the OD traffic volume in the link unit to the OD traffic volume in the region unit. ). As described above, since the error of the OD traffic volume Q1 is large, using the coefficient when converting the OD traffic volume Q2 reduces the error when performing the reverse conversion.
The ground device includes position information grasping means for grasping the position of the vehicle, information collecting means for collecting information of the identification code of the in-vehicle device, and information and position information of the identification code of the in-vehicle device collected by the information collecting means. Based on the position information of the vehicle grasped by the grasping means, the traveling route identifying means for identifying the traveling route of the vehicle equipped with the in-vehicle device, and the traveling between ODs based on the traveling route identified by the traveling route identifying means OD traffic volume specifying means for specifying the route and OD traffic volume estimating means for estimating the OD traffic volume Q1 based on the specified inter-OD travel route per unit time may be provided. . According to the inter-OD travel route determination device having this configuration, the ground device collects the identification code information of the in-vehicle device, and based on the collected identification code information and the vehicle position information, the travel route of the vehicle Is identified. Then, the inter-OD travel route is determined based on the travel route specified by the travel route specifying means, and the OD traffic volume Q1 is estimated based on each inter-OD travel route.
[0014]
The ground device includes a plurality of road communication devices that communicate with the vehicle-mounted device, and a center device that collects information on each road communication device, and the position information grasping means is installed on the road communication device through which the vehicle has passed. The position of the vehicle is grasped based on the position information, and the travel route specifying means connects the roads where the on-road communication device that communicates with the in-vehicle device is connected, so that the vehicle equipped with the in-vehicle device is connected. A travel route may be specified (claim 8). This configuration relates to an embodiment of the present invention in which a road communication device is installed on a road, the vehicle position is grasped by the road communication device, and information on identification codes of the in-vehicle device is collected.
[0015]
The travel route specifying means may calculate the optimum route between the roads where the road communication device is installed to connect the roads where the road communication device communicated with the in-vehicle device is connected (claim) Item 9). When the road communication device is not installed on all roads, an optimum route between the roads on which the road communication device is installed is calculated, and the optimum route is set as a vehicle travel route.
Further, the position information grasping means may grasp the position of the vehicle by acquiring vehicle position detection information from the in-vehicle device by communication (claim 10). This configuration relates to an embodiment of the present invention in which the vehicle position information and the identification code information of the in-vehicle device are collected in the ground device using the position detection function of the in-vehicle device.
[0016]
(2) The OD traffic volume determination method of the present invention is a method according to the same invention as the OD traffic volume determination device described in claims 1, 2 and 3, respectively (claims 11, 12, and 13). (3) The OD traffic volume determination device of the present invention uses the OD traffic volume Q1 obtained based on communication between the in-vehicle device and the ground device to determine the OD traffic volume Q with higher accuracy. An apparatus for determining traffic volume, an expansion means for multiplying a coefficient by OD traffic volume Q1, an optimum route calculation means for calculating an optimum route from an OD traffic generation point (O) to an extinction point (D), and a coefficient A point traffic volume calculating means for calculating the point traffic volume at each point by running the OD traffic volume from the occurrence point (O) to the disappearance point (D) along the optimum route, and the point traffic at each point. The point traffic volume measuring means for measuring the volume, the spot traffic volume calculated by the spot traffic volume calculating means, and the spot traffic volume measured by the spot traffic volume measuring means coincide with each other with a predetermined error or less. Coefficient determining means for determining the coefficient The expansion means, based on the determined coefficient, determine the OD traffic volume Q and the coefficient multiplying the OD traffic volume Q1, and outputs the OD traffic volume Q (claim 14).
[0017]
This OD traffic volume determination device is intended to increase the accuracy of OD traffic volume Q1, multiplying the obtained OD traffic volume Q1 by a coefficient, and the OD traffic volume with the coefficient from the generation point (O) to the disappearance point Until (D), the vehicle travels along the optimum route to calculate the point traffic volume at each point, and the calculated point traffic volume and the point traffic volume measured at each point are less than a predetermined error. The coefficient is determined so as to coincide with each other, and based on the determined coefficient, the OD traffic volume Q1 is multiplied by a coefficient to obtain the OD traffic volume Q, and the OD traffic volume Q is output. By this processing, the coefficient can be appropriately selected, and the accuracy of the OD traffic volume Q1 can be improved. The coefficient may be determined for each link or may be determined uniformly in each region.
[0018]
The coefficient may be a coefficient in consideration of a mounting rate of the in-vehicle device (claim 15). If the coefficient considering the mounting rate of the in-vehicle device is used, there is an advantage that it becomes a guide when determining the initial value of the coefficient.
(4) The OD traffic volume determination method of the present invention is a method according to the same invention as the OD traffic volume determination device according to claims 14 and 15 (claims 16 and 17).
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
-Road beacon-
FIG. 1 is an installation diagram of a road beacon B that functions as a road communication device. The road beacon B has a light emitter / receiver B1 disposed at a position overlooking the road at the top of the pole, and a control device B2 installed beside the pole. The control device B2 is connected to a center device A described later by a wired communication line.
[0020]
The road beacon B is a road communication function that performs two-way communication with the in-vehicle device C using light of a predetermined wavelength, and irradiates a short pulse optical signal toward the road, and reflects the reflected light to the vehicle passing underneath. It has a vehicle detection function to detect passage. Note that the communication medium of the road beacon B is not limited to light, and may be radio waves.
FIG. 2 is a flowchart for explaining a procedure for transmitting data from the road beacon B to the center apparatus A when focusing on the road communication function.
[0021]
The road beacon B collects information from the in-vehicle device C in the storage device B2 (step S1). Data collected from the in-vehicle device C to the road beacon B includes data such as a vehicle identification code, vehicle type information, a beacon code that has passed the previous time, and a travel time from the time when the previous beacon passed.
The identification code may be a code unique to a vehicle, an in-vehicle device, or an individual. Moreover, the code | cord | chord which the road beacon B generate | occur | produced and assigned by the random number at the specific timing may be sufficient, and the number assigned in order to the passing vehicle may be sufficient.
[0022]
If the fixed transmission cycle is reached (step S2), data is transmitted to the center apparatus A (step S3). The center device A accumulates the received information (step S4).
Table 1 shows a list of information collected from a plurality of road beacons B and accumulated in the center apparatus A.
[0023]
[Table 1]

[0024]
It should be noted that the implementation of the present invention is not limited to the form in which the position of the vehicle is detected using the road communication device. For example, the in-vehicle device has a vehicle position detection function such as GPS (Global Positioning System), and the identification code and the information of the vehicle detection position are taken into the ground device from the in-vehicle device, and the ground device is similar to the center device A described later. It is also possible to obtain | require the driving | running route between OD of each vehicle by providing the structure of. In this case, the communication between the in-vehicle device and the ground device may be performed regularly or irregularly using a mobile phone, a car phone, or a dedicated line.
[0025]
―Road network―
FIG. 3 is an area map of a road network where road beacons, cameras, and the like are installed.
In this map, a plurality of roads are drawn vertically and horizontally, and there are intersections. The road between the intersections is regarded as one link unit, and uplink and downlink links L1 to LN (N = 48 in FIG. 3) are configured. Cross links between the links are intersection nodes N1, N2,..., N9.
[0026]
A road beacon is installed at a position where it enters an intersection from each link, and is indicated by a black triangle. In addition, although the road beacon is drawn in FIG. 3 as being installed at each intersection, there is actually an intersection that is not installed. Moreover, it may be installed other than the position entering the intersection. Cameras are installed everywhere overlooking a certain range of roads.
In addition, narrow streets are connected from the middle of the road, and parking lots of stores and houses exist along the road. In FIG. 3, narrow streets and parking lots are drawn only on some roads for the sake of drawing, but in reality, narrow streets are connected to most roads and parking lots exist.
[0027]
―Center device―
FIG. 4 is a functional block diagram in the center apparatus A. The cylindrical shape in FIG. 4 shows the memory belonging to each part.
The center device A includes an input conversion unit 1 that converts a transmission / reception signal to / from a road beacon B, an input conversion unit 2 that converts a camera image signal, a travel time measurement unit 8, an optimum route tree calculation unit 9, and a road beacon B. A traffic volume measurement unit 3 that calculates a point traffic volume based on a vehicle detection signal of the vehicle, and an OD traffic volume estimation unit 6 that estimates an OD traffic volume Q2 based on the point traffic volume calculated by the traffic volume measurement unit 3 ing.
[0028]
Further, based on the transmission / reception signal of the road beacon B and the image signal of the camera, the vehicle identification code, the passage time, the vehicle type, the code of the beacon that has passed the previous time, and the data of the travel time from the time when the previous beacon passed are obtained and stored. The data totaling unit 4 stored in the memory, the data stored in the memory of the data totaling unit 4 is taken out, and the OD travel route calculating unit 5 that obtains the travel route between ODs based on the data or the like, It has an OD traffic volume estimation unit 7 that estimates the OD traffic volume Q1 by processing.
[0029]
And the hybrid processing part 10 which determines final OD traffic volume Q based on both OD traffic volume Q1 and Q2 is provided.
The center device A includes a computer, a memory, an input / output device, and the like, and all or part of the functions of the processing units 3 to 10 are realized by the computer executing a program recorded in the memory.
Hereinafter, each process performed by the travel time measurement unit 8, the optimum route tree calculation unit 9, the traffic volume measurement unit 3, the OD travel route calculation unit 5, the OD traffic volume estimation unit 6, the OD traffic volume estimation unit 7, and the hybrid processing unit 10 Will be described in order using a flowchart if necessary.
[0030]
-Link travel time measurement-
The travel time measuring unit 8 measures the link travel time as follows.
Using the point traffic volume measurement q, occupation time O, and average vehicle length (constant value) I, the vehicle average speed V is calculated by the formula V = I · q / O, and the link length Using L, the link travel time T is calculated by the formula T = L / V.
In addition, the vehicle plate number is matched from the camera measurement image to identify the vehicle, and it is necessary to travel the link from the time when the same vehicle passes the link end and the other end of the link. Time T 'is obtained. If there are a plurality of vehicles passing through the unit time, the average of the link travel times T ′ of the vehicles is taken.
[0031]
Then, either the link travel time T or the link travel time T ′ obtained as described above, or the weighted average thereof is taken as the link travel time for each time zone. Note that a filter value may be used to absorb travel time measurement errors. Since there are variations depending on the day of the week, time zone, weather, etc., past statistical values may be taken into account.
―Calculation of optimal route tree―
The optimum route tree calculation unit 9 calculates the optimum route tree as follows. The optimum route tree is a set of optimum routes that use any link as a starting link and reach all links in the area (see Japanese Patent Laid-Open No. 7-244798). Since there is only one optimum route from the departure link to another specific link, the optimum route tree spreads from the departure link in a tree shape and does not intersect again in the future.
[0032]
In order to calculate the optimum route tree, the link travel time obtained by the travel time measurement unit is used, but a link distance may be used in addition to this.
The optimum route tree calculation unit calculates an optimum route tree with all links in the area as departure links. Therefore, if there are N links in the area, N optimal route trees are obtained.
-Traffic measurement-
The traffic volume measuring unit 3 calculates the point traffic volume (the number of vehicles passing per unit time (for example, 5 minutes)) based on the sensing signal of the road beacon B obtained from the input conversion unit 1. Since the road beacon B is installed for each link, the point traffic is also obtained for each link. Therefore, it is hereinafter referred to as “link point traffic volume”.
[0033]
Furthermore, the traffic volume measuring unit 3 detects the occupation time O (the total sum Σtk of the times tk when each vehicle k crosses the vehicle detector within a unit time (for example, 5 minutes)).
-OD travel route calculation-
FIG. 5 is a flowchart for explaining the OD travel route calculation process performed by the OD travel route calculation unit 5.
First, the vehicle identification code, the passage time, the vehicle type, the beacon code that passed the previous time, and the travel time data from the time when the previous beacon passed (Table 1) are stored in the memory of the data totaling unit 4. Obtain (step W1). The data is sorted for each identification code and stored in the memory (step W2). This information is called “basic information”. Table 2 is a list of basic information. According to Table 2, for example, the information of the in-vehicle device having the identification code “1357” is collected in a lump.
[0034]
[Table 2]

[0035]
Next, data of the same vehicle identification code is extracted from the basic information (step W3). Based on the data of this same vehicle identification code, it rearranges in order of a passing beacon (step W5). Thereby, the passed beacon can be specified in the passing order. Moreover, the travel time between passing beacons can be calculated.
The road beacon that has passed at the latest time represents the disappearance point (D) of the vehicle, and the road beacon that has passed the earliest and is flagged as “no beacon passed last time” represents the vehicle generation point (O).
[0036]
Next, a travel route between passing beacons is obtained (step W7). Since the road beacon B is usually installed at each intersection as shown in FIG. 3, the traveling route between passing beacons is a road connecting the intersections. However, when the road beacon B is not installed at each intersection, the travel route is not uniquely determined, so the optimum route between the passing beacons is calculated based on the known Dijkstra method, potential method, etc. No. 7-244798). To calculate the optimum route, either the link travel time or the link distance may be used as a base.
[0037]
Whether or not the vehicle has actually traveled on the calculated optimal route cannot be determined 100%. However, since the possibility that the vehicle has traveled on the optimal route is the highest, the vehicle is considered to have traveled on the optimal route, and this is used as the travel route.
-OD traffic volume calculation based on inter-OD travel route-
If the above OD travel route is obtained for each vehicle equipped with the in-vehicle device C, the OD traffic volume estimation unit 7 classifies the obtained inter OD travel route of each vehicle by region and time zone. The OD traffic volume Q1, which is the number of vehicles per unit time, is generated from a certain point and disappears at other points based on the inter-OD travel route of each vehicle for each region and time zone.
[0038]
-OD traffic calculation based on traffic measurement-
Next, a method of calculating the OD traffic volume Q2 using the link point traffic volume obtained by the traffic volume measuring unit 3 will be described. As described in [Problems to be Solved by the Invention], various methods are adopted. In this [Embodiment of the Invention], the patent application of the same applicant, described in Japanese Patent Application No. 2000-233430, is described. The OD traffic calculation method will be described. According to this method, a certain amount of traffic is set on the departure link, traffic is distributed along the route tree at the branching portion of the route tree, and the vehicle is simulated while partially erasing the traffic on the link. Thus, the passing traffic volume at each link is obtained. From the passage traffic obtained by selecting each link in the area as the departure link, a passage probability matrix that links the point traffic volume of the link and the link generated traffic volume is obtained, and this passage probability matrix and the point measured by the link Based on the traffic volume measurement value, the link generated traffic volume can be calculated.
[0039]
Then, along the route tree searched for each link as a starting link, the link-generated traffic volume is distributed at the branching portion of the route tree, and a simulated run is performed while partially annihilating the traffic volume at the link. Estimate traffic volume.
-Calculation of pass probability matrix H-
A method of calculating the passage probability matrix H performed by the OD traffic volume estimation unit 6 will be described.
FIG. 6 is a flowchart for explaining a method of calculating the passage probability matrix H.
[0040]
First, the OD traffic volume estimation unit 6 acquires a link point traffic volume measurement value obtained from the traffic volume measurement unit 3 based on the detection signal of the vehicle detector (step X1). Since this link point traffic volume measurement value has the number N of links, it can be handled as an N-dimensional vector.
Next, a link generated traffic volume setting value and a link disappearance traffic volume setting value are calculated (step X2).
[0041]
As shown in FIG. 3, normally, one vehicle detector is installed per link, and it is rare that the vehicle detector is installed at the end point and the start point of the link.
Therefore, as shown in FIG. 7, a certain node (for example, N5), links L12, L25, L27, and L30 flowing into the node N5 and links L11, L26, L28, and L29 flowing out from the node are 1 Assuming that there are two regions, the region generated traffic volume generated in this region or the region disappeared traffic amount J disappeared per unit time is considered. According to the example of FIG. 7, the area generated traffic volume or the area disappeared traffic volume J is determined from the traffic volume Qout flowing out through the four links L11, L26, L28, and L29, and the four links L12, L25, L27, and L30. The traffic volume Qin flowing in through is subtracted. When J is positive, the area generated traffic volume J> 0 and the area disappearing traffic volume = 0, and when negative, the area disappearing traffic volume | J |> 0 and the area generated traffic volume = 0.
[0042]
The value obtained by dividing the traffic generated by the area by the number of links flowing out is called the “link generated traffic setting value”, and the value divided by the number of links flowing out the area disappearing traffic is set as the “link annihilating traffic setting value”. " If the number of outflowing links is 4, the link generated traffic volume setting value is a quarter of the area generated traffic volume, and the link disappearance traffic volume setting value is a quarter of the area disappearing traffic volume.
FIG. 8 is a link diagram for explaining the link generated traffic volume setting value or the link disappearance traffic volume setting value. FIG. 8A shows the link generated traffic volume setting value when the region generated traffic volume J> 0. Indicates that the link disappearance traffic volume setting value is 0, and FIG. 8B shows that when the area disappearance traffic volume J> 0, the link disappearance traffic volume setting value is J / 4, and the link generation traffic volume. The amount setting value is 0.
[0043]
The reason why the area generated traffic volume and the area disappeared traffic volume are both divided by the number of “outflow” links is to avoid duplication of the processing results and links in other nodes. Of course, both the area generated traffic volume and the area disappeared traffic volume may be divided by the number of “inflow” links.
Although it is a rough approximation because it is divided by the number of links, the “link generated traffic volume” can be calculated with high accuracy by using a mathematical method as described later.
If the accuracy is not important, the link generated traffic volume setting value can be used as the “link generated traffic volume” as it is.
[0044]
Next, an optimum route tree having a certain link in the area as a departure link is acquired from the optimum route tree calculation unit 5 (step X3).
Then, a certain amount of traffic is simulated and traveled along the optimal route tree (step X4).
The processes in steps X3 and X4 are repeated by changing the departure link (step X5).
[0045]
Based on these travel results, a passage probability matrix is calculated (step X6).
Hereinafter, the contents of steps X4 to X6 will be described in detail.
When simulating a certain amount of traffic along the optimal route tree, the traffic is distributed to each link at a predetermined rate at each node of the optimal route tree and disappears at a predetermined rate after distribution. Then, it is assumed that the traffic remaining on each link after extinction (this is referred to as “link passing traffic”) is distributed again at the next node, and a predetermined ratio disappears.
[0046]
If the traffic volume of the departure link is 1, the passing traffic volume naturally takes a value smaller than 1. Since the passing traffic volume is obtained by the number of links, it can be described by an N-dimensional vector. This is hereinafter referred to as “passing traffic vector”.
The following three methods a1, method a2, and method a3 are conceivable as methods for distributing the traffic volume.
Method a1: A partial route tree connected to each link ahead of a node is considered together (this is referred to as a “route block”), and the sum of link extinction traffic setting values of links constituting the route block is obtained. In this method, distribution is performed in proportion to the sum.
[0047]
FIG. 9 is a diagram showing an example of a route tree corresponding to the road map of FIG. 3, and the departure link is the link L1. The links ahead of the link L1 are L3, L6, and L7. The link ahead of the link L3 does not exist in this area, and the constituent link of the route block B1 is only L3. A path block including the links L22, L25, L24,... Ahead of the link L6 is indicated by B2, and a path block including the links L9, L12, L13,.
[0048]
For each link constituting the route block, a sum JBi of link extinction traffic volume setting values is obtained. For the route block B1, JB1 becomes the link disappearance traffic volume setting value of the link L3. For the route block B2, JB2 is the sum of the link extinction traffic volume setting values of the links L6, L22, L25, L24,. The reason why the link generated traffic volume setting value of each link constituting the route block is not considered is that the link generated traffic volume is considered at the departure link of each route tree (steps X3 and X5).
[0049]
Method a2: This is a method in which the total sum of link point traffic volume measurement value × link distance of each link constituting the route block is obtained and distributed at a ratio proportional to the total.
Method a3: The ratio of straight left / right turns at the intersection is used. The straight / left / right turn ratio can be obtained statistically by accumulating the travel route of each vehicle based on information from the vehicle detector and the camera. Of course, if there is a significant difference depending on the day of the week, time zone, weather, etc., these conditions may be taken into consideration.
[0050]
The following two methods b1 and b2 are conceivable as methods for eliminating the traffic at the link.
Method b1: Using the link disappearance traffic setting value of the link, the ratio
(Link disappearance traffic volume setting value) / (Link point traffic volume measurement value)
It is a method to disappear with.
Method b2: A method of annihilating at a certain probability according to the travel distance.
[0051]
When the vehicle generated on the road network travels, it disappears with a certain probability distribution according to the travel distance. If this probability distribution is written as P (u) (where u is the travel distance), the probability that the vehicle will disappear before traveling the distance u is:
[0052]
[Expression 1]

[0053]
It is represented by P (∞) = 1.
Therefore, the probability Pn−1 of traveling from the departure link to the optimal route tree and disappearing at the point of passing the nth link from the departure link Pn−1 The probability of annihilation at the link can be obtained.
The form of the probability distribution F (t) is preferably obtained numerically from travel data of a large number of vehicles. In this embodiment, for the sake of simplicity, it is assumed that the probability distribution F (t) is a normal distribution with an average distance m and variance σ. (We believe that the actual distribution will be close to the normal distribution).
[0054]
[Expression 2]

[0055]
As described above, a certain amount of traffic is simulated along the optimal route tree, the passing traffic vector is obtained, the departure link is changed, the same processing is performed, and the passing traffic vector is obtained. When all the departure links are completed, N passing traffic vectors are obtained, and this can be written in a matrix form. This matrix is referred to as a “pass probability matrix” H.
-Calculation of traffic volume generated by links-
Next, the link generated traffic volume x is calculated. The link generated traffic volume x is defined as “the traffic volume flowing out from the end point of the link within the unit time minus the traffic volume flowing into the starting point of the link”. In other words, it can be understood as the subtraction of the traffic volume that enters the narrow street in the middle of the link, emerges from the narrow street, enters the parking lot, or exits the parking lot. Since this link-generated traffic volume x is also equal to the number N of links, it can be handled as an N-dimensional vector.
[0056]
The relationship between the link generated traffic volume x and the link point traffic volume measurement value q is calculated using the passage probability matrix.
q = Hx (2)
x = H ^-1 q
It becomes. Therefore, based on the link point traffic volume measurement value, the link generated traffic volume x can be calculated using the passage probability matrix.
[0057]
With the above processing, the passing probability matrix H is calculated using the method a1, the method a2 or the method a3 as a method for distributing the traffic volume, and using the method b1 or the method b2 as a method for eliminating the traffic volume. However, these methods are approximate methods, and actually the link point traffic volume measurement value q includes an error. If the error is written as η, equation (2) becomes
q = Hx + η (3)
It becomes.
[0058]
When the variance of the link-generated traffic volume x and the variance of the error η are known in Equation (3), the accurate link-generated traffic volume x can be estimated using Bayesian estimation.
The link generated traffic volume setting value a, the link generated traffic volume x variance Σ, and the error η variance R are expressed as follows.
a = E (x) a: Link generated traffic volume setting value
Σ = cov (x) Σ: Variance of link generated traffic x
R = cov (η) R: variance of error η
Link generation traffic x can be estimated using Bayesian estimation.
[0059]
Γ ^-1 = Σ ^-1 + H'R ^-1 H H ': Transpose matrix of H
x = Γ (H'R ^-1 q + Σ ^-1 a)
On the other hand, when there is a constraint condition on the link generated traffic volume x, for example, when the upper and lower limit values of the link generated traffic volume x (but less than the traffic capacity) are set, Equation (3) is established as much as possible. The link generated traffic volume x can be estimated using a quadratic programming method.
[0060]
Σ | η _i The link generated traffic volume x is estimated so that | becomes the minimum value. That is, the link generated traffic volume x is obtained by obtaining the minimum value of (Hx−q) ′ (Hx−q).
However, the constraint condition is 0 ≦ x _i ≦ X _i (X _i Is the upper limit of xi)
(Hx−q) ′ (Hx−q) = (1/2) x ′ (2H′H) x + (−2H′q) ′ x + q′q
= (1/2) x'Gx + C'x + q'q G: Positive definite symmetric matrix
It is.
[0061]
-Estimation of OD traffic volume Q2-
FIG. 10 is a flowchart for explaining a method of estimating the OD traffic volume Q2.
First, the OD traffic volume estimation unit 6 acquires the link point traffic volume measurement value q at regular time intervals (step Y1), and calculates the link generated traffic volume as described above (step Y2). An optimum route tree is obtained using each link as a departure link (step Y3).
[0062]
For each departure link, a certain amount of link-generated traffic is run according to the optimal route tree, traffic is distributed at the branch of the tree, and extinguished traffic is generated at the link to direct the traffic toward the end of the tree. It will be washed away (Step Y4). The process ends when all the traffic has disappeared.
As a result, the passage time and disappearance time of each link can be statistically grasped for a predetermined percentage of the generated vehicles (step Y5).
[0063]
As a result, the OD traffic volume Q2 can be estimated. Table 3 below is an example of a table that grasps the passing time and disappearance time of each link for the generated vehicle.
[0064]
[Table 3]

[0065]
―Hybrid processing―
Next, a hybrid process for taking a weighted average of the OD traffic volumes Q1, Q2 will be described.
FIG. 11 is a flowchart for explaining the flow of the hybrid process.
The OD traffic volumes Q1 and Q2 obtained by the processing so far are defined for each link. For this reason, there are few absolute numbers of the number of vehicles, and when processing based on this, there is a risk that errors will increase. Therefore, the OD traffic volumes Q1, Q2 are summarized for each region (steps Z1, Z2).
[0066]
FIG. 12 is a diagram for explaining a method of grouping by region.
FIG. 12 (a) is a table showing the OD traffic volume for each link. The unit time generated from the link Li (i = 1,2, ..) and disappears at the link Lj (j = 1,2, ..). The number of units is listed.
FIG. 12 (b) is a table showing the OD traffic volume grouped by region. The number of units per unit time that are generated from the region Ri (i = 1,2, ..) and disappear in the region Rj (j = 1,2, ..) is shown. One or more links correspond to each region. The OD traffic volume in a certain area is the sum of the OD traffic volumes of one or more links in the area.
[0067]
For example, it is assumed that a certain area R1 includes links L1 and L2, and a certain area R2 includes links L3 and L4. OD traffic volume Q2 that originates from link L1 and disappears at link L3 is a, OD traffic volume Q2 that originates from link L1 and disappears at link L4 is b, OD traffic volume Q2 that originates from link L2 and disappears at link L3 is c Let OD be the OD traffic volume Q2 that originates from the link L2 and disappears at the link L4.
The OD traffic volume Q2 that occurs in the region R1 and disappears in the region R2 is a + b + c + d.
[0068]
Next, the OD traffic volume Q1 is subjected to an expansion process considering the mounting rate of the in-vehicle device (step Z3). That is, the OD traffic volume of all vehicles is obtained by multiplying the OD traffic volume of the vehicle equipped with the in-vehicle device by the reciprocal of the ratio of the vehicle equipped with the in-vehicle device and all vehicles. The “loading ratio” is a function of date, time zone, region, and the like.
Or, even if the ratio of total OD traffic Q1 and total OD traffic Q2 in the wide-area ΣRi (i covers all areas where OD traffic is determined) is estimated, Good. The wide area may be all over Japan or a prefecture. In the wide area, the mounting rate φ is obtained by the following equation.
[0069]
φ = (Total OD traffic Q1 in wide area) / (Total OD traffic Q2 in wide area)
The OD traffic volume Q1 of all vehicles in the area Ri can be obtained by multiplying the OD traffic volume Q1 of the vehicle equipped with the vehicle-mounted device in the area Ri by the reciprocal 1 / φ of the mounting rate.
Then, the OD traffic volume Q is obtained by taking a weighted average of the OD traffic volume Q1 (after expansion) and the OD traffic volume Q2 (step Z4). If expressed by the formula,
OD traffic volume Q = α (expanded OD traffic volume Q1) + (1-α) (OD traffic volume Q2)
It becomes. α is a weighting factor (0 ≦ α ≦ 1) for each region Ri.
[0070]
Then, the OD traffic volume Q is converted into a link unit (step Z5). That is, the local OD traffic volume is distributed to the OD traffic volume of one or a plurality of links included in the local area. This conversion can be performed by performing a reverse calculation of the process in which the OD traffic volume Q2 performed in step Z2 is summarized for each region.
For example, a / (a + b + c + d) may be applied in order to obtain the OD traffic volume generated from the link L1 and disappearing at the link L3 from the OD traffic volume Q2 generated at the area R1 and disappearing at the area R2.
[0071]
Although it is conceivable to perform the reverse calculation of the processing performed in step Z1, the absolute number of the number of vehicles is particularly small (for example, OD in link units) because the on-vehicle device mounting rate depends on the OD traffic volume Q1. Some traffic volume Q1 shows a value such as a = 0), and if this value is calculated backward, there is a risk of increasing errors, which is not preferable.
After the OD traffic volume is converted into a link unit, the optimum route from a certain occurrence point O to the disappearance point D is calculated and regarded as a travel route, and the traffic is simulated. Then, this process is performed for all occurrence points O and all disappearance points D (step Z6). Thereby, the passing traffic volume of each link can be calculated.
[0072]
Next, the calculated passing traffic volume of each link is compared with the link point traffic volume measurement (step Z7). As a result of the comparison, there is no difference in each link or the ratio r should be 1. However, otherwise (NO in step Z8), the difference is as close to 0 as possible in each link or the ratio r. Is changed so as to be as close to 1 as possible (step Z9), the process returns to step Z4, and the above-described processing is repeated.
[0073]
If the absolute value of the difference is smaller than the threshold value or the absolute value | r-1 | of the difference between the ratio r and 1 is smaller than the threshold value, the OD traffic volume Q is output (in step Z8). YES). The threshold is preferably set to an appropriate value by verifying the OD traffic volume determination process of the present invention for a number of models.
With the above processing, the OD traffic volume Q1 obtained by directly measuring the OD travel route of the vehicle and the OD traffic volume Q2 estimated indirectly from the measurement data of the point traffic volume are used to obtain a more accurate OD traffic volume. Traffic volume Q can be obtained.
[0074]
If the above OD traffic volume Q is used, the traffic volume in each time zone can be predicted for each link, which can be used for traffic volume prediction and traffic volume control.
In the description using FIG. 11, the processing steps Z1 and Z2 that are grouped for each region and the processing step Z5 that converts to a link unit are performed. However, these processings are omitted, and the processing is performed in units of links. May be.
-Processing based only on OD traffic volume Q1-
Next, although not strictly speaking a hybrid process, a process for obtaining the OD traffic volume Q from only the OD traffic volume Q1 will be described. This corresponds to a case where α = 1 is always set in the average calculation in step Z4, and a coefficient (step Z3) corresponding to the reciprocal of the in-vehicle rate is obtained more accurately.
[0075]
FIG. 13 is a flowchart for explaining processing of only the OD traffic Q1.
First, an expansion process for multiplying the OD traffic Q1 by a coefficient is performed (step Z11). The coefficient may be set for each link or for each region.
Next, as in FIG. 11, an optimal route from a certain occurrence point O to the disappearance point D is calculated and regarded as a travel route, and the traffic is simulated. Then, this process is performed for all occurrence points O and all disappearance points D (step Z12). Thereby, the passing traffic volume of each link can be calculated.
[0076]
Next, the calculated passing traffic volume of each link is compared with the point traffic volume measurement of the link (step Z13). As a result of the comparison, there is no difference between the links or the ratio r should be 1. If not (NO in step Z14), the difference is as close to 0 as possible for each link or the ratio r. The coefficient is changed so as to be as close to 1 as possible (step Z15), the process returns to step Z11 and the above-described processing is repeated.
[0077]
If the absolute value of the difference is smaller than the threshold value or the absolute value | r-1 | of the difference between the ratio r and 1 is smaller than the threshold value, the OD traffic volume Q is output (in step Z14). YES).
Thereby, the exact OD traffic volume Q can be calculated | required only from OD traffic volume Q1.
[0078]
【The invention's effect】
As described above, according to the OD traffic volume determination device or method of the present invention, the traffic volume between ODs can be obtained with good accuracy. Therefore, it can be used for traffic volume prediction and traffic volume control based on accurate OD traffic volume.
[Brief description of the drawings]
FIG. 1 is a layout diagram of a road beacon B. FIG.
FIG. 2 is a flowchart for explaining a procedure for transmitting data from a road beacon B to a center device.
FIG. 3 is an area map of a road network where road beacons B, cameras, and the like are installed.
FIG. 4 is a functional block diagram of the center device.
FIG. 5 is a flowchart for explaining an OD travel route calculation process performed by an OD travel route calculation unit 5;
FIG. 6 is a flowchart for explaining a method of calculating a passage probability matrix H.
FIG. 7 is an intersection link diagram for explaining area generated traffic volume or area disappeared traffic volume.
FIG. 8 is a link diagram for explaining a link generation traffic volume setting value or a link disappearance traffic volume setting value;
FIG. 9 is a link diagram showing an example of a route tree corresponding to the road map of FIG. 3;
FIG. 10 is a flowchart for explaining an OD traffic volume estimation method;
FIG. 11 is a flowchart for explaining the flow of hybrid processing;
FIG. 12 is a diagram for explaining a method of collecting OD traffic volume for each region.
FIG. 13 is a flowchart for explaining a process of increasing the OD traffic volume Q1 in consideration of the mounting rate of the in-vehicle device and increasing its accuracy.
[Explanation of symbols]
1 Input converter
2 Input converter
3 Traffic volume measurement unit
4 data aggregation department
5 OD travel route calculator
6 OD Traffic Volume (Q2) Estimator
7 OD Traffic Volume (Q1) Estimator
8 Travel time measurement part
9 Optimal route tree calculator
10 Hybrid processing section
A Center device
B Road beacon
B1 Emitter / receiver
B2 control device
C In-vehicle device

Claims (17)

OD for determining more accurate OD traffic volume Q using OD traffic volume Q1 obtained based on communication between in-vehicle device and ground device and OD traffic volume Q2 obtained by traffic measurement A traffic determination device,
An average calculating means for calculating a weighted average of the OD traffic Q1 and the OD traffic Q2,
An optimum route calculating means for calculating an optimum route from an OD traffic generation point (O) to an extinction point (D);
A point traffic volume calculating means for calculating the point traffic volume at each point by running the weighted averaged OD traffic volume along the optimum route from the occurrence point (O) to the disappearance point (D);
A point traffic measuring means for measuring the point traffic at each point;
The weighting factor for the average calculation is determined so that the spot traffic calculated by the spot traffic calculation means and the spot traffic measured by the spot traffic measurement means match within a predetermined error or less. Weighting factor determination means for
The average calculation means obtains the OD traffic volume Q by performing a weighted average calculation of the OD traffic volume Q1 and the OD traffic volume Q2 based on the determined weight coefficient, and outputs the OD traffic volume Q. A characteristic OD traffic volume determination device. OD traffic volume expansion means for correcting the OD traffic volume Q1 calculated based on the communication between the in-vehicle device and the ground device in consideration of the mounting rate of the in-vehicle device;
2. The OD traffic volume determination device according to claim 1, wherein the average calculation means performs a weighted average calculation of the expanded OD traffic volume Q1 and the OD traffic volume Q2. The mounting ratio of the in-vehicle device is determined by obtaining a ratio of the OD traffic volume Q1 and the OD traffic volume Q2 over a wider area than the area where the OD traffic volume Q is to be determined. 2. OD traffic volume determination device according to 2. Conversion that converts the OD traffic volume Q1 calculated based on the communication between the in-vehicle device and the ground device and the OD traffic volume Q2 calculated by the traffic volume measurement from the OD traffic volume of the link unit to the OD traffic volume of the local unit. And a reverse conversion means for reversely converting the OD traffic volume in the region unit to the OD traffic volume in the link unit,
The average calculation process is performed based on the local unit OD traffic volume, and the point traffic volume calculating unit calculates the point traffic volume of each point based on the reverse-converted link unit OD traffic volume. The OD traffic volume determination device according to claim 1, wherein the OD traffic volume determination device is performed. Conversion that converts the OD traffic volume Q1 calculated based on the communication between the in-vehicle device and the ground device and the OD traffic volume Q2 calculated by the traffic volume measurement from the OD traffic volume of the link unit to the OD traffic volume of the local unit. And a reverse conversion means for reversely converting the OD traffic volume in the region unit to the OD traffic volume in the link unit,
The enlargement and average calculation processing of the OD traffic volume is performed based on the OD traffic volume of this region unit, and the process of calculating the point traffic volume of each point by the point traffic volume calculation means is performed in the reversely converted link unit. 3. The apparatus according to claim 2, wherein the determination is made based on the OD traffic volume. The inverse conversion means performs an inverse conversion using an inverse number of a conversion coefficient used when converting the OD traffic volume Q2 from the OD traffic volume of the link unit to the OD traffic volume of the local unit. The OD traffic volume determination device according to claim 4 or 5. The ground device is
Position information grasping means for grasping the position of the vehicle;
Information collecting means for collecting information on the identification code of the in-vehicle device;
A travel route identifying means for identifying a travel route of a vehicle on which the vehicle-mounted device is mounted based on the information on the identification code of the vehicle-mounted device collected by the information collecting device and the position information of the vehicle grasped by the position information grasping device; ,
OD traffic volume specifying means for specifying a driving route between ODs based on the driving route specified by the driving route specifying means;
The OD traffic volume determination device according to claim 1, further comprising: an OD traffic volume estimation unit configured to estimate the OD traffic volume Q 1 based on the specified travel distance between each OD per unit time. The ground device includes a plurality of road communication devices for communicating with a vehicle-mounted device, and a center device that collects information on each road communication device,
The position information grasping means grasps the position of the vehicle based on the installation position information of the on-road communication device through which the vehicle has passed,
8. The travel route specifying means specifies a travel route of a vehicle on which the in-vehicle device is mounted by connecting roads on which road communication devices communicating with the in-vehicle device are connected. OD traffic volume determination device. The travel route specifying means calculates an optimum route between roads where the road communication device is installed to connect roads where the road communication device communicated with the in-vehicle device is connected. 8. OD traffic volume determination device according to 8. 8. The OD traffic determination device according to claim 7, wherein the position information grasping means grasps the position of the vehicle by acquiring vehicle position detection information from the in-vehicle device by communication. OD for determining more accurate OD traffic volume Q using OD traffic volume Q1 obtained based on communication between in-vehicle device and ground device and OD traffic volume Q2 obtained by traffic measurement A traffic determination method,
Calculate the weighted average of OD traffic Q1 and OD traffic Q2,
Run the weighted and averaged OD traffic along the optimal route from the point of occurrence (O) to the point of disappearance (D), and calculate the point traffic at each point.
Determining the weighting factor for the average calculation so that the calculated point traffic and the point traffic measured at each point match within a predetermined error or less,
Based on the determined weighting factor, the OD traffic volume Q is obtained by calculating a weighted average of the OD traffic volume Q1 and the OD traffic volume Q2, and outputting the OD traffic volume Q. Decision method. The OD traffic volume Q1 required based on the communication between the in-vehicle device and the ground device is corrected in consideration of the in-vehicle device mounting rate.
12. The OD traffic determination method according to claim 11 , wherein a weighted average calculation is performed on the expanded OD traffic Q1 and the OD traffic Q2. The mounting ratio of the in-vehicle device is determined by obtaining a ratio of the OD traffic volume Q1 and the OD traffic volume Q2 over a wider area than the area where the OD traffic volume Q is to be determined. 12. OD traffic volume determination method according to 12. An OD traffic determination device for determining a more accurate OD traffic Q using an OD traffic Q1 obtained based on communication between an in-vehicle device and a ground device,
Expansion means to multiply the OD traffic volume Q1 by a factor,
An optimum route calculating means for calculating an optimum route from an OD traffic generation point (O) to an extinction point (D);
A point traffic volume calculating means for calculating the point traffic volume at each point by running the OD traffic volume with a coefficient from the occurrence point (O) to the disappearance point (D) along the optimum route;
A point traffic measuring means for measuring the point traffic at each point;
Coefficient determining means for determining the coefficient so that the spot traffic calculated by the spot traffic volume calculating means and the spot traffic measured by the spot traffic measuring means are equal to or less than a predetermined error. ,
The expansion means determines the OD traffic volume Q by multiplying the OD traffic volume Q1 by a coefficient based on the determined coefficient, and outputs the OD traffic volume Q. The OD traffic volume determination device according to claim 14, wherein the coefficient is a coefficient in consideration of a mounting rate of an in-vehicle device. An OD traffic determination method for determining a more accurate OD traffic Q using an OD traffic Q1 obtained based on communication between an in-vehicle device and a ground device,
Multiply the OD traffic volume Q1 by a factor,
Run the OD traffic volume with a coefficient from the point of occurrence (O) to the extinction point (D) along the optimal route, and calculate the point traffic volume at each point.
The coefficient is determined so that the calculated spot traffic volume and the spot traffic volume measured at each spot match within a predetermined error or less,
An OD traffic volume determination method characterized in that, based on the determined coefficient, the OD traffic volume Q1 is multiplied by a coefficient to obtain an OD traffic volume Q, and the OD traffic volume Q is output. The OD traffic volume determination method according to claim 16 , wherein the coefficient is a coefficient in consideration of a mounting rate of an in-vehicle device.

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