Method for traffic situation determination on the basis of reporting vehicle data for a traffic network with traffic-controlled network nodes

• US 6,470,262 B2
• Filed: 05/10/2001
• Issued: 10/22/2002
• Est. Priority Date: 05/10/2000
• Status: Expired due to Fees

• Current Assignee: Georgetown University, Daimler Chrysler Company LLC (Stellantis NV)
• Original Assignee: Daimler Chrysler Company LLC (Stellantis NV)
• Inventors: Kerner, Boris, Rehborn, Hubert
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): MANCHO, RONNIE M
• Application Number:
  US09/851,993
• Publication Number:
  US 20020026277A1
• Time in Patent Office: 530 Days
• Field of Search: 701/200-215, 701/117-119, 701/23-26, 340/905, 340/934, 340/995, 340/988, 340/989, 340/990, 455/456, 180/65.8, 320/107
• US Class Current: 701/117
• CPC Class Codes: G08G 1/0104 Measuring and analyzing of parameters relative to traffic conditions

Abstract

A method for determining the traffic situation is based on traffic data which are obtained from reporting vehicles moving in the traffic, for a traffic network with traffic-controlled network nodes and roadway sections connecting them. Traffic data indicative of travel times on the roadway sections are obtained by reporting vehicles moving in the traffic, and are used to determine travel times on a roadway-section-specific basis. The mean number of vehicles in the queue, the mean number of vehicles, the mean vehicle speed outside the queue, the mean waiting time in the queue and/or the mean vehicle density outside the queue are determined from these travel times for the respective roadway section.

Claims

1. A method for determining a traffic situation based on traffic data obtained by reporting vehicles moving in the traffic, for a traffic network with traffic-controlled network nodes and roadway sections connecting them, said method comprising:

reporting vehicles moving in the traffic obtaining traffic data indicative of travel times (t_tr^(j,k)) on particular roadway sections (j, k);

determining roadway specific travel times for the particular roadway sections from the traffic data obtained; and

determining at least one of the following traffic situation parameters from the roadway-section specific travel times;

(i) a mean number (N_q^(j,k)) of vehicles in a queue at the particular roadway section (j, k) before an associated traffic-controlled network node;

(ii) a mean number (N^(j,k)) of vehicles on the particular roadway section (j, k);

(iii) a mean speed (V_free^(j,k) of vehicles on the particular roadway section (j, k) between a roadway section start and a queue start;

(iv) a mean waiting time (t_q^(j,k)) in a network node queue on the particular roadway section (j, k); and

(v) a mean density (p^(j,k)) of vehicles on the particular roadway section (j, k) between the roadway section start and the queue start.

2. The method according to claim 1, wherein the travel times (t_tr^(j,k)) and the traffic situation parameter or parameters are determined specifically for each direction lane set (k) of the particular roadway section (j).

3. The method according to claim 1, wherein the traffic situation parameter value or values obtained from the determined roadway-section specific travel times are used continuously for producing at least one of:

historical progress lines relating to the mean number of vehicles in a particular queue;

length of the particular queue;

mean waiting time in the queue and/or the mean number of vehicles on the particular roadway section (j, k).

4. The method according to claim 1, wherein turn-off rates are used as further traffic situation parameters obtained from determined roadway-section specific travel times, which turn-off rates in each case indicate a rate of vehicles which travel from an incoming direction lane set via a network node into an outgoing direction lane set.

5. The method according to claim 1, wherein:

a threshold value (t_s^(j,k)) is predetermined in accordance with the relationship

6. The method according to claim 1, wherein the roadway-section-specific vehicle situation parameters comprising the mean vehicle density (p^(j,k)) outside the queue, the mean number of vehicles (N^(j,k)), the mean number of vehicles in the queue (N_q^(j,k)), queue length (L_q^(j,k)) and waiting time (t_q^(j,k)) in the queue for the subsaturated state are obtained by means of the following equation system:

${\mathrm{\rho <br><br>}}^{\left(j,k\right)}=\frac{N^{\left(j,k\right)}-N_q^{\left(j,k\right)}}{n^{\left(j,k\right)}<br><br>\left(L^{\left(j,k\right)}-L_q^{\left(j,k\right)}\right)}$$N^{\left(j,k\right)}=q_{\mathrm{sat}}^{\left(j,k\right)}<br><br>t_{\mathrm{tr}}^{\left(j,k\right)}<br><br>\frac{t_{\mathrm{tr}}^{\left(j,k\right)}-\left[L^{\left(j,k\right)}/v_{\mathrm{free}}^{\left(j,k\right)}<br><br>\left({\mathrm{\rho <br><br>}}^{\left(j,k\right)}\right)\right]-{{\mathrm{\beta <br><br>}}^{\left(j,k\right)}<br><br>\left(T_R^{\left(j,k\right)}\right)}^2/T^{\left(j,k\right)}}{t_{\mathrm{tr}}^{\left(j,k\right)}-\left[L^{\left(j,k\right)}/v_{\mathrm{free}}^{\left(j,k\right)}<br><br>\left({\mathrm{\rho <br><br>}}^{\left(j,k\right)}\right)\right]-{\mathrm{\gamma <br><br>}}^{\left(j,k\right)}<br><br>{{\mathrm{\beta <br><br>}}^{\left(j,k\right)}<br><br>\left(T_R^{\left(j,k\right)}\right)}^2/T^{\left(j,k\right)}}$$N_q^{\left(j,k\right)}=q_{\mathrm{sat}}^{\left(j,k\right)}<br><br>\left[t_{\mathrm{tr}}^{\left(j,k\right)}-L^{\left(j,k\right)}/v_{\mathrm{free}}^{\left(j,k\right)}<br><br>\left({\mathrm{\rho <br><br>}}^{\left(j,k\right)}\right)-{{\mathrm{\beta <br><br>}}^{\left(j,k\right)}<br><br>\left(T_R^{\left(j,k\right)}\right)}^2/T^{\left(j,k\right)}\right]/\left(1-{\mathrm{\gamma <br><br>}}^{\left(j,k\right)}\right)$$L_q^{\left(j,k\right)}=b^{\left(j,k\right)}<br><br>N_q^{\left(j,k\right)}/n^{\left(j,k\right)}$$t_q^{\left(j,k\right)}=\left[t_{\mathrm{tr}}^{\left(j,k\right)}-L^{\left(j,k\right)}/v_{\mathrm{free}}^{\left(j,k\right)}<br><br>\left({\mathrm{\rho <br><br>}}^{\left(j,k\right)}\right)-{\mathrm{\gamma <br><br>}}^{\left(j,k\right)}<br><br>{{\mathrm{\beta <br><br>}}^{\left(j,k\right)}<br><br>\left(T_R^{\left(j,k\right)}\right)}^2/T^{\left(j,k\right)}\right]/\left(1-{\mathrm{\gamma <br><br>}}^{\left(j,k\right)}\right)$

and for the supersaturated state are obtained by means of the following equation system;

$\begin{array}{c}{\mathrm{\rho <br><br>}}^{\left(j,k\right)}=\text{\hspace{1em}<br><br>}<br><br>\frac{N^{\left(j,k\right)}-N_q^{\left(j,k\right)}}{n^{\left(j,k\right)}<br><br>\left(L^{\left(j,k\right)}-L_q^{\left(j,k\right)}\right)}\\ N^{\left(j,k\right)}=\text{\hspace{1em}<br><br>}<br><br>t_{\mathrm{tr}}^{\left(j,k\right)}<br><br>q_{\mathrm{sat}}^{\left(j,k\right)}<br><br>T_G^{\left(j,k\right)}/T^{\left(j,k\right)}\\ N_q^{\left(j,k\right)}=\text{\hspace{1em}<br><br>}<br><br>q_{\mathrm{sat}}^{\left(j,k\right)}<br><br>T_G^{\left(j,k\right)}<br><br>\left[t_{\mathrm{tr}}^{\left(j,k\right)}-L^{\left(j,k\right)}/v_{\mathrm{free}}^{\left(j,k\right)}<br><br>\left({\mathrm{\rho <br><br>}}^{\left(j,k\right)}\right)\right]/\left[\left(1-{\mathrm{\gamma <br><br>}}_t^{\left(j,k\right)}\right)<br><br>T^{\left(j,k\right)}\right]\\ L_q^{\left(j,k\right)}=\text{\hspace{1em}<br><br>}<br><br>b^{\left(j,k\right)}<br><br>N_q^{\left(j,k\right)}/n^{\left(j,k\right)}\\ t_q^{\left(j,k\right)}=\text{\hspace{1em}<br><br>}<br><br>N_q^{\left(j,k\right)}<br><br>T^{\left(j,k\right)}/\left(T_G^{\left(j,k\right)}<br><br>q_{\mathrm{sat}}^{\left(j,k\right)}\right),\end{array}$

where

7. The method according to claim 1, wherein:

traffic situation parameters comprising the mean number of vehicles (N^(j,k)), effective continuous roadway section inlet flow (q_in^(j,k)) and effective continuous queue inlet flow (q_in/q^(j,k)) are obtained from traffic data from at least two reporting vehicles which are traveling at a time interval (Δ

t^(j,k)) greater than or equal to a traffic control period duration (T^(j,k)) on the same roadway section (j, k), using the difference (Δ

t_tr^(j,k)) between determined travel times of the reporting vehicles; and

the relationship;

8. The method according to claim 1, wherein:

an overfull roadway section is deduced if a reporting vehicle is located on the relevant roadway section (j, k) for a time period greater than a critical travel time (t_tr,crit^(j,k)), being a determined travel time that satisfies an implied relationship

9. The method according to claim 1, wherein sources and sinks of vehicle flow on the traffic network are taken into account in determining traffic situation parameters by means of corresponding inlet flows (_Tq^(j,k)) and outlet flows (_Ts^(j,k)) to and from the particular roadway section (j, k).

10. The method according to claim 9, wherein:

the traffic network which is considered for determining the traffic situation comprises only a predeterminable portion of all roadway sections and network nodes in an overall traffic network; and

roadway sections and network nodes that are not considered in this case are regarded as sources and sinks of vehicle flow on the traffic network under consideration.