FAQ: Bus Acceleration as part of the BüLaMo Project (Bürgerlabor Mobilität Münsterland)
Questions and Answers at a glance
What is being done at Weseler Straße / Geiststraße / Moltkestraße and why?
In the BMBF-funded research project "Bürgerlabor Mobilität Münsterland", RWTH Aachen University is planning to speed up buses traveling into the city along the Weseler Straße. To achieve this, the following measures are to be taken on the section of road between the intersections Weseler Straße / Geiststraße and Weseler Straße / Moltkestraße the existing control concepts are to be revised and supplemented by special bus phases.
The current traffic light control includes a green wave for car traffic along Weseler Straße. However, this green wave cannot be used for buses traveling into the city for two reasons: (1) due to the stop at Geiststraße, the buses are no longer part of the green wave and the green wave and (2) at the intersection of Weseler Straße and Moltkestraße, almost all buses turn right into Moltkestraße and arrive at the intersection shortly after the end of the green right-turners arrive at the intersection. In order to reduce the waiting times for buses at the two intersections buses at the two intersections, a special phase is to be activated when a bus arrives, in which only the buses and the traffic flows not in conflict with the bus are given the green light. As soon as the bus has passed the intersection, the system switches back to normal control program.Copyright: © ISAC
What are the temporary traffic lights for?
The special feature of planned traffic light control is that the special bus phase is only switched if the thermal cameras in the vicinity of the two intersections do not detect any unusual backlogs in the vicinity of the two intersections. This backlog detection is not provided in the existing traffic light system. For this reason, a temporary traffic light system must be set up for the test period.
What are the cameras for?
The thermal cameras installed in the vicinity of the two intersections serve for the detection of car traffic. As soon as a camera detects a backlog that exceeds the usual level, a message is sent to the traffic light control system that no special bus phase may be activated until the backlog has been reduced.
How long will the traffic light control be tested?
According to current plans, the new traffic light control system will be put into operation in the week after fall vacation period (17.-21.10.2022) and will be tested until the start of Münster Christmas Market (21.11.2022). During this period, data will be collected continuously to assess the effectiveness of the control system and to analyze the impact on other traffic. If, contrary to expectations, the impact on car traffic is greater than in traffic simulation, the temporary traffic light system can switch back to the existing traffic light control at any time.
Is the planned traffic light control safe?
Yes. All technical precautions that make a traffic light system safe are also in place for the planned traffic light control. This includes, for example, the monitoring of intermediate times, which ensures that there is sufficient time between the green times of two conflicting traffic flows.
What effects will the planned traffic light control have on bus traffic?
The Institute of Highway Engineering at RWTH Aachen University has tested the planned traffic light control system in extensive traffic simulations. On average, travel time for buses will be will be reduced from 210 seconds to 173 seconds between the intersection of Weseler Straße / Koldering and the intersection of Weseler Straße / Moltkestraße. This corresponds to a saving of 18%. These values are only average values. Depending on traffic situation and the stopping time at Geiststraße, travel time can be longer or shorter. This applies to both the existing and to the planned traffic light control. With the planned control, long travel times in particular occur much less frequently.
The RVM express buses (e.g. lines X90/S90) have a slightly lower travel time reduction, because they do not stop at Geiststraße and therefore arrive more often at the intersection Weseler Straße/Geiststraße during the green wave. In the opposite direction, a slight travel time reduction from 94 s to 88 s (6%) can be achieved, because the buses at the intersection Weseler Straße/Geiststraße do benefit indirectly from the special bus phase.
What impact will the planned traffic light control have on car traffic?
Several measures will be taken to minimize the impact on vehicular traffic: (1) the arrival time of the buses at the intersections is predicted as accurately as possible, so that the special phase for the buses is as short as possible. (2) The green wave is maintained by inserting the special bus phase between the regular phases, without canceling or delaying too much any regular phase. One round trip (the time after which the control program repeats itself) lasts 90 s in any case, regardless of whether it is with or without special phase. (3) The traffic situation in the vicinity of the two intersections is continuously monitored by thermal cameras. As soon as a backlog is detected on one lane that exceeds the usual level, a message is sent to the traffic light control system that no special phase may be activated until the backlog has been cleared.
In traffic simulation, during the morning rush hour (6-9 a.m.), in the vicinity of the two intersections (6-9 a.m.), a travel time increase of 3.0 s on average was determined, which corresponds to an increase of 1.4%. The waiting times of the individual traffic flows are shown in the figure below. The specification from the Guidelines for Dimensioning of Road Traffic Facilities (HBS) that for each traffic flow at least quality level D (corresponding to an average waiting time of 70 s) is met.
What effects will the planned traffic light control have on bicycle traffic?
It is ensured that, as with the existing traffic light control system, each traffic stream of both bicycle and pedestrian traffic receives green once in each round (90 s). Even if the green times traffic flows are slightly shortened, the minimum green times (6-20 s depending on the traffic flow) are always depending on the traffic flow) are observed in any case.
What impact will the planned traffic signal control have on pedestrian traffic?
It is ensured that, as with the existing traffic light control system, each traffic stream both bicycle and pedestrian traffic receives green once in each round (90 s). Even if the green times of individual traffic flows are slightly shortened, the minimum green times (14-20 s depending on the traffic flow) are traffic flow) are observed in any case.
Are visually impaired pedestrians also taken into account?
Yes. Like the existing system, the planned traffic light system has request buttons for the visually impaired. As with the existing facility, these are active between 6:00 am and 9:00 pm. If the request buttons are pressed, an enabling tone sounds at the following green time
How are the arrival times of buses at the intersections predicted?
When the buses approach the two intersections, they pass so-called virtual reporting points. At these points, a message is sent by radio to the traffic light control system. From the distance to the intersection, the remaining driving time is calculated, assuming that the buses are driving that the buses travel at 40 km/h and stop at the Geiststraße stop for an average of 15 seconds. Each bus passes several reporting points on its way to the intersection, so that the prediction of the arrival time is updated several times even in case of traffic-related delays.
How is it ensured that data protection is ensured?
Thermal cameras are used. Thermal cameras record only the thermal radiation emitted by objects. Accordingly, only the outlines of the objects are recognizable, but not license plates or faces can be recognized. People and objects cannot be recognized.
Is it possible to look inside apartments / offices / vehicles?Copyright: © ISAC
No. Window panes have a uniform temperature and thus appear as a homogeneous surface in the image of thermal cameras. This makes it impossible to see people, objects, etc. behind the windows. There is no view into your private sphere.
How does the detection of traffic work?
An automatic detection based on artificial intelligence recognizes individual objects in the image of the thermal cameras and classifies them as motorcycle, car, truck, bus, pedestrian, cyclist and e-scooter rider.
How does traffic jam detection work?
Zones have been defined for each thermal camera. In real time is calculated several times per second what percentage of the zone is occupied by objects. If this percentage exceeds a defined fast value over a defined period of time, a jam is detected. The threshold value depends on how strongly the zones are occupied with the existing traffic light control.
What are the white antennas on the devices for?
Each device can be reached via WLAN on site and via LTE from a distance. This serves the communication of the data described above, but also allows software to be updated remotely.
What happens to the data?
All images are processed on site at the intersection. Based on the detection of objects these are counted. The counting data as well as occupancy levels in defined areas are transmitted to RWTH Aachen University once a day. The videos are not normally stored, but however, individual videos are saved for testing purposes.