EP1413999B1 - Method to generate implicit information from FCD - Google Patents

Abstract

The method involves determining the last FC message for the same journey on receiving an FC message, reconstructing the path traveled between the messages from their position and time data by searching alternative routes, determining a mean speed or time for the route between the messages and/or turn frequencies and waiting times, generating information via a traffic information system using the data and sending to road users. The method involves determining the last floating car or FC message for the same journey on receiving an FC message, reconstructing the path traveled between the messages from their position and time information by searching alternative routes, determining a mean speed or time for the route between the messages and/or turn frequencies and waiting times, generating information via a traffic information system using the data obtained and sending to road users directly or via information services

Description

The invention relates to a method for generating implicit information from FC data for Determination of travel times and detection for accident clearance.

In traffic, traffic conditions can be very due to different influences change quickly. Resulting traffic disturbances, e.g. Traffic jams pose a threat to this following road users. About current traffic reports or on Route-based travel time-based route recommendations become road users Such disturbances, also for safety reasons to avoid accidents, Brought knowledge.

In addition to locally based sensors that record traffic readings, "Floating Car Data (FCD)" used by vehicles "floating" in traffic, to be delivered. These usually transmit a short-term history of driven Speed values. The transmission is triggered by various criteria, in particular by falling below a speed level for a certain time. This will detect traffic jams. Such a method is e.g. from the WO 99/24952 known.

However, the transmitted measured value history covers only a small part of the closer Past. Especially in metropolitan areas, the information contained implicitly therein not evaluated over free routes and free intersections and used, because the vehicle preferably reports when entering congestion events. These Information is however for the interpretation of the traffic situation and for good routes or even Diversion recommendations, especially in metropolitan areas, are as important as knowledge about Jam events.

• Der Ablauf jeder halben Stunde;
• durchfahrene Distanz von 30 Kilometern;
• Unterschreiten eines Geschwindigkeitsniveaus für eine bestimmte Zeit.

Floating cars are constantly collecting speed scores. Triggered by certain criteria, these data are transmitted together with time and location information to a central data processing, eg via SMS or trunked radio. The location information is obtained from GPS measurements (Global Positioning System) and, if necessary, by matching these position data with a stored digital map. Criteria that cause a transmission of the last collected speed values can be eg:

• The expiration of every half hour;
• traveled distance of 30 kilometers;
• Fall below a speed level for a certain time.

The transmission therefore usually takes place asynchronously in time depending on the fulfilled criterion. In particular, the latter criterion is used for the detection of congestion events in the the vehicle has entered.

In the center then the sequence of location and time information along with the Speed values, ie sequences of (x, t, v) -triplings, compared with a digital map. In the digital map, a road consists of a sequence of sections, also called "road elements (RE) "Can the individual road elements along the tripel beyond doubt be located, the result is a complete sequence of road elements passed through. If there are doubts about the way through in the case of several alternative routes then so this list may also have gaps. From this list of localized road elements Then the route taken by the vehicle is reconstructed.

There is no known method which currently implicit information about not by FCD directly covered sections of a road or turning in Automatically determine and use agglomerations of data from floating cars.

The invention is therefore based on the object, the information contained implicitly win, evaluate and suitably interpret or exploit.

The invention solves the task of extraction, evaluation, interpretation and Utilization of implicit information according to the characteristics of the Claim 1. Advantageous embodiments are specified in the subclaims.

The method of the invention provides a robust solution to this problem. It is open all types of roads, both inside and outside, to determine clearances and Junction crossings based on FCD can be used. It is therefore also for the creation of Travel times and traffic reports as well as for direct vehicle control and traffic control and for many other services.

1. Bei Empfang eines FC-Telegrammes Bestimmung des letzten FC-Telegrammes der gleichen Fahrt.

2. Rekonstruktion der Strecke, welche die herkömmliche explizite Rekonstruktion nicht abdeckt, über eine geeignet gewählte Wegesuche.

3. Bestimmung der mittleren Reisegeschwindigkeit oder der Reisezeit für die in der Strecke enthaltenen Teilstrecken.

4. Weiterverarbeitung dieser mittleren Reisegeschwindigkeit oder der Reisezeit zu einem Verkehrszustand, in der Regel dicht oder frei, geltend für die betreffenden Teilstrecken.

5. Weiterverarbeitung der Reisezeit zu einer "Überquerungszeit", geltend für Kreuzungen oder Kreuzungsübergänge, die auf der durchfahrenen Strecke liegen.

6. Erfassung von relativen Abbiegehäufigkeiten je Start- und Zielrichtung, z.B. auch als mittlere Funktion der Tageszeit, für Kreuzungen in Ballungsräumen.

7. Berücksichtigung dieser mittleren Reisegeschwindigkeit oder dieser Reisezeit bzw. der daraus abgeleiteten Verkehrszustände von Strecken oder Kreuzungen in Routenplanungen oder anderen Diensten.

The process according to the invention is structured as follows:

1. When receiving an FC telegram, determine the last FC telegram of the same trip.

2. Reconstruction of the route, which does not cover the conventional explicit reconstruction, via a suitably chosen route search.

3. Determination of the average cruising speed or travel time for the sections included in the route.

4. Further processing of this average cruising speed or the travel time to a traffic condition, usually dense or free, valid for the relevant sections.

5. Further processing of the travel time to a "crossing time", valid for intersections or crossings, which lie on the traversed route.

6. Recording of relative turn-off frequencies for each start and finish direction, eg also as an average function of the time of day, for intersections in agglomerations.

7. Consideration of this average cruising speed or this travel time or the traffic conditions derived therefrom of routes or intersections in route planning or other services.

• offline zur Auslegung von Kreuzungen,
• bei genügend hohem Anteil von FCs am Verkehrsaufkommen auch online, z.B. zur Ampelphasensteuerung, sein.

Another application may be the capacity estimate of intersections per turn

• offline for intersection design,
• with a sufficiently high share of FCs in the traffic also online, eg for traffic light phase control, be.

If there are several alternatives for a possible route of a vehicle, these alternatives are assigned probabilities which, depending on their weighting, the Probability that a vehicle passes through the corresponding route indicates.

The generated traffic information is called traffic information or as Route recommendations communicated to road users.

Reference to the accompanying drawings, the invention will be explained in more detail below.

FIG. 1 shows the location of road elements 2 along a series of measuring points x a direction of travel 1, which transmits the floating car (FC) 4 to a central station. Result is a consequence of traversed road elements 2. From this is the travel of the vehicle in the form of reconstructed route 3.

FIG. 2 shows the reconstruction of the travel path along a direction of travel 1 between two FC messages of the same vehicle 4 by using the between by road elements. 2 reconstructed localized routes 3 obtained implicitly localized route 5.

FIG. 3 shows the reconstruction of the turning behavior at an intersection. For example, send a vehicle 4, because it was stuck in a traffic jam in front of an intersection, and it later announces itself somewhere else, so is on a turning process according to the direction of travel 1 closed.

However, since the FC transmits only a small part of its measured value history and this is mainly triggered by congestion events, it only provides information for the parts of the route that are explicitly "marked" by triples with measured value information. There is no explicit information for the routes between the message positions.
The transmitted information may also be represented in other form than triples, eg as a sequence of route information (x1, x2, t1, t2, v), where x1 and x2 denote the beginning and the end of a route, t1 and t2 designate the times, where the vehicle reached x1 or x2, and v stands for the mean speed on the track.

From the knowledge that there are two FC telegrams to the control center about the same Vehicle and knowing the possible alternative routes from a digital map, the distance between the two directly reconstructable sections can be determined (Figure 2). In other words, in successive telegrams of the same Ride contained implicit information is used to reconstruct the previously unreconstructed Used route.

This will be done by searching for a journey between the last few triples of the Predecessor telegram and the temporally first triples of the successor telegram the possible route alternatives in the form of road element lists. For several Alternatives are taking into account the travel times and speeds and the Routes and possibly a-priori knowledge of these routes probabilities for Path alternatives set.

An implementation has shown that in this way on average about an additional 50% of the otherwise In the telegrams directly covered route reconstructed and thus interpretable still within a limit of e.g. current past 20 minutes. The greater part of this is attributable to agglomerations in connection with a Truck-based FCD fleet.

1. die mittlere Reisegeschwindigkeit: seien (x1, t1, v1) und (x2,t2,v2) die Tripel, welche die fragliche Strecke einschließen, so gilt: v_mittel = (x2-x1)/(t2-t1).

2. die Reisezeit: t_Reise = t2-t1.

3. aus der mittleren Reisegeschwindigkeit wird auf den Verkehrszustand geschlossen und die Strecke je nach Geschwindigkeitseinteilung als stockend, dicht oder frei ausgewiesen. Ist beispielsweise für diese Strecke durch eine öffentliche Verkehrsmeldung noch ein Stau ausgewiesen, so wird diese "Stauinformation" aufgehoben und für die Strecke wieder "frei" gemeldet, noch bevor die Meldung durch die öffentliche Quelle abgemeldet wird. Dadurch ergibt sich eine geringere Abmeldeverzögerung in solchen Fällen.

4. In Ballungsräumen werden Kreuzungen bzw. Kreuzungsübergänge als frei erkannt.

5. In Ballungsräumen werden damit Abbiegehäufigkeiten und -verhältnisse an Kreuzungen und damit typische richtungsabhängige Kreuzungsbelastungen über die Zeit erfaßbar. Daraus können z.B. folgende mittlere Schätzwerte über die Tageszeit (vgl. Fig. 3) abgeleitet werden:

• wieviel Prozent der aus Richtung (a) kommenden Fahrzeuge biegen in Richtung (b) ab;
• welche Reisezeit bzw. Wartezeit entsteht an dieser Kreuzung von Richtung (a) nach (b);
• wie stark, gemessen an der Gesamtkapazität, ist die Kreuzung von (a) nach (b) ausgelastet;
• wie hoch ist die Gesamtkapazität (bzw. der maximal mögliche Fahrzeugfluß gemessen in Fahrzeugen pro Zeiteinheit) der Kreuzung mindestens von (a) nach (b);

Since the information obtained mainly informed about relatively freely passable routes, otherwise the FC would have reported directly, the following interpretations are made for implicitly reconstructed routes:

1. the mean cruising speed: let (x1, t1, v1) and (x2, t2, v2) be the triples, which include the distance in question, then: v_mittel = (x2-x1) / (t2-t1).

2. the travel time: t_rise = t2-t1.

3. from the average cruising speed is closed to the traffic condition and the route depending on the speed classification as halting, dense or free. If, for example, a traffic jam is still reported for this route as a result of a public traffic report, this "traffic jam information" is canceled and reported "free" again for the route, even before the message is deregistered by the public source. This results in a lower logoff delay in such cases.

4. In metropolitan areas, crossings or crossings are recognized as free.

5. In metropolitan areas, turn-off frequencies and relationships at intersections and thus typical direction-dependent intersection loads can be detected over time. From this, for example, the following mean estimated values can be derived over the time of day (see Fig. 3):

• what percentage of the vehicles coming from direction (a) turn in direction (b);
• what travel time or waiting time arises at this intersection from direction (a) to (b);
• how much, in terms of total capacity, is the intersection of (a) to (b) busy;
• what is the total capacity (or the maximum possible vehicle flow measured in vehicles per unit time) of the intersection at least from (a) to (b);

From normal FCD-Stautelegrammen, which results from waiting times at intersections leaves they do not identify themselves as they typically only cover the area before the intersection.

Claims (7)

1. Method for generating implicit information from FC data for determining trip times, intersection transit times, and for incident detection in a road network,
   characterized in that

   upon reception of an FC message, the last FC message from the same trip is identified;

   using the position and time information from the two messages, the path traveled between the two messages, which is not explicitly described by this information, is reconstructed as well by means of a route search of alternative routes;

   for the path traveled between the two messages, an average travel speed or a trip time is determined, and/or turn frequencies and turn wait times are determined for intersections along the entire travel path;

   using the trip times or travel speeds for this path on a road and/or the turn frequencies and turn wait times at intersections, information is produced by traffic information systems and is communicated directly or indirectly to road users through information services.
2. Method according to claim 1,
   characterized in that
   a traffic condition for this reconstructed path is determined from the trip time or travel speed.
3. Method according to one of the preceding claims
   characterized in that
   a trip time or turn wait time for an intersection is determined from the trip time or travel speed.
4. Method according to one of the preceding claims
   characterized in that
   mean values of turn frequencies for each origin direction and destination direction are determined for intersections as a function of the time of day.
5. Method according to one of the preceding claims
   characterized in that
   a traffic advisory currently in effect is corrected or discontinued on the basis of the trip time or travel speed or on the basis of the traffic condition derived therefrom;
6. Method according to one of the preceding claims
   characterized in that
   when multiple alternative routes exist, the various alternatives are assigned probabilities for weighted further processing.
7. Method according to one of the preceding claims
   characterized in that
   the traffic information is communicated in the form of traffic advisories or by means of routing recommendations based on trip times or travel speeds.

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