DE102005002872A1 - Destination guiding method for e.g. bus, involves using appropriate statistical factors for calculating travel time of vehicle on traffic route, by taking into consideration waiting periods of vehicle at traffic light signal systems - Google Patents

Abstract

The method involves using appropriate statistical factors for calculating travel time of vehicle e.g. bus, on a traffic route, by taking into consideration the waiting periods of the vehicle at traffic light signal systems. Locations of traffic light signal systems are specifically marked in a digital road map material. A left turning vehicle is differentiated from a right turning vehicle at a crossing. An independent claim is also included for a device for guiding a vehicle to a destination.

Description

The The invention relates to a method and a device for vehicle guidance.

The digital maps of navigation systems and route planners for vehicle guidance is by street categories and according to the rules of the Highway Code (STVO) and taken into account no current circuits of traffic signal systems (LSA).

Green and red phases The traffic signal systems have an enormous impact on the travel time in the inner city Traffic network and lead to fluctuations or changes the calculated travel time between 20% and 50% due to additional Hold times, even in normal, so traffic jam-free, traffic. These loss times caused by the traffic lights increase proportional to the number of traffic lights per kilometer in Dependence on Coordination and intersection geometry as well dependent on to the competing and cruising cross traffic, such as Pedestrians, vehicles of public Local transport, such as buses or trams, with driving permission.

measurements in city traffic show that on a driving distance of 10 kilometers in the city center often 40 light signal systems with 20 stops and 10 minutes service life occur. The intersection geometry defines this the ratio of Green and Red-time and the traffic volume the length of the backwater. The arrival time of the vehicle determines the waiting time in addition to Circulation of the traffic signal system.

These by the traffic lights conditional parameters currently find in the route planning or the vehicle targeting no consideration. Ranges with speed specifications (such as 30 km / h) and turn relations are indeed in the algorithm for route calculation integrated, but not the influence of time - dependent loss times on the Nodes of traffic lights, static arrival times and traffic-dependent tailback periods.

Of the Invention is based on the object, a method and an apparatus for vehicle guidance to create, so that caused by traffic lights loss time considered in the route planning or vehicle guidance and on an inner-city Traffic route network routes with minimum service life can be selected preferentially.

These The object is achieved by the features specified in claims 1 and 6 solved the invention. Further developments of the invention are defined in the subclaims.

Of the Advantage of the invention is in particular that in the inner city Traffic to route those traffic lights on a proposed route can be taken into account.

following The invention will be explained in more detail with reference to the drawings. Show:

1 : Illustration of several routes with traffic lights

2 : schematic representation of a junction with traffic signal system

In 1 the technical design of a FCD (Floating Car Data Technology) based route planning is shown. In the first step, the average travel times on an inner-city traffic route network are recorded and the locations of the traffic signals in the digital road map material are specially marked. In the figure, intersection nodes with traffic signal system are represented by a circle and pedestrian crossings with signal system by a rectangle.

In the in 1 example chosen is between the points A and B, a road network drawn. Between both points, for example, the distances a, b and c arise.

On the route a are three traffic lights, on the route b five traffic lights and on the route c eight traffic lights. Generally revealed thus for a special route a specific route length and an equally specific number of traffic lights.

each Traffic signal system is characterized by an individual, medium holding time characterized. Dependent on from the orbital period and green time can then take into account the statistical time of arrival the middle one Waiting time per intersection with traffic signal / s estimated, being coordinated "green waves" and road-bound Buses must also be considered in the algorithm.

Δt_R

= Rotzeit pro Umlauf (Ampelzyklus)

N·Δt_R

= verlängerte Rotzeit aufgrund Rückstaus mit N größer oder gleich 0 (N ≥ 0) und N = ganze Zahl

τ

= durch zufällige Ankunftszeit bedingte Verkürzung der Rotzeit

The holding time h at a traffic signal is composed of: h = Δt R + N · Δt R -Τ (1) With

Δt _R

= Red time per circulation (traffic light cycle)

N · Δt _R

= extended red time due to backflow with N greater than or equal to 0 (N ≥ 0) and N = integer

τ

= shortening of the red time due to random arrival time

If the arrival time is outside the blackout period (red phase), the vehicle may pass the intersection at green. In this case, τ = Δt _R and N = 0, so that a holding time h = 0 results.

mit

λ_i

= statistischer Faktor der Lichtsignalanlage i

σ_i

= mittlere Wartezeit an der. Lichtsignalanlage i

Λ

= statistischer Faktor für die Gesamtstrecke

σ _i

= mittlere Wartezeit pro Lichtsignalanlage

Since N and τ are not known for the route planning, an approximation must be found for the holding time at the traffic signals. According to the invention, an estimated holding time σ of:

With

λ _i

= statistical factor of the traffic light system i

σ _i

= mean waiting time at the. Traffic light i

Λ

= statistical factor for the total distance

σ _i

= average waiting time per traffic signal

The average waiting time σ _i is individual for each traffic signal system. Equally individual is the statistical factor λ _i , for which the following applies: λ i ~ k and λ i ~ t F / (T R + t F )

In this case, k corresponds to a coordination factor with which, for example, a "green wave" can be taken into account in the route planning based on FCD (floating car data) data Moreover, the statistics factor λ _{i is} also proportional to the ratio of the release time (green time) t _F and Rotzeit t _R., Ie with this factor the probability can be estimated, with which one can pass the light signal system i without waiting time.

Since these statistic factors λ _i and σ _{i are} generally not available for every signal system, the estimation shown in equation (2) can be made for the average holding time over the entire distance AB. Accordingly, a mean waiting time of σ _{i is} used for each of the m traffic lights lying on the route AB. The sum of the total waiting times is then multiplied by the statistical factor A for the total distance. In this factor A, for example, the coordination and density of the light signal systems of the total distance is taken into account.

In one example, it can be assumed that the mean waiting time σ _{i is} about 20 seconds. However, if you are on a main route with "green wave", the total waiting time may be reduced to half per traffic signal, resulting in Λ = 0.5.

The estimation of the total waiting time on a route can be improved by including in the calculation whether the driver should turn left at an intersection, turn right or drive straight ahead. A corresponding sketch for this is 2 refer to. Accordingly, upon arrival at an intersection, which is represented by a circle, in principle the waiting time σ _i until the traffic light system is set to green. Depending on whether the route now plans to drive straight ahead at the intersection, turn left or turn right, there may be additional waiting times or shortening of the waiting time. Thus, for example, a "green wave" can be taken into account in the statistics factor λ _{i, 1} for driving straight ahead.When turning right, one may have to let pedestrians pass, so that the waiting time increases, which can be taken into account with the statistical factor λ _{i, 2} In this way, additional latency for left turn may result from the right of oncoming straight-ahead traffic, reflected in the statistic factor λ _{i, 3.} These directional factors may be considered at each intersection, so using equation (2), an improved estimation of total waiting time.

Claims (10)

A method for vehicle guidance by - determining a travel time of a route, characterized in that - in determining the travel time an influence is taken into account by at least one traffic signal system. The method of claim 1, wherein an average hold time is taken into account at the at least one traffic signal system. The method of claim 1 or 2, wherein a left turn is distinguished from a right turn at an intersection. Method according to one of the preceding claims, wherein a route is determined based on the travel time. Method according to one of the preceding claims, wherein a coordination factor for consideration a plurality of successively arranged traffic signal systems for determining the driving time is used. Device for vehicle guidance A computing device for Determining a travel time of a route, characterized, that - With the computing device an influence by at least one traffic signal system Considerable when determining the travel time is. Apparatus according to claim 6, wherein a middle one Holding time at a traffic signal by the computing device berücksichtigbar is. Apparatus according to claim 6 or 7, wherein with the Computation a left turn from a right turn a crossing is distinguishable. Device according to one of claims 6 to 8, wherein a travel route based on the travel time can be determined. Device according to one of claims 6 to 9, wherein in the computing device several light signal systems arranged one behind the other by a coordination factor berücksichtigbar are.