factsheet 09
PT-priority and facilities operational transport
Description of the project
Implementing selective detection at traffic lights makes it possible to reduce time lost for PT-vehicles and operational transport.
Refers to specific measures
RD18a, PT 27.
Dependencies
The largest improvements can be achieved at intersections which are not overloaded. Because at these intersections traffic control can be the most flexible and will give less delay to the other vehicles.
Objectives of the project
Achieving higher performance of PT with less differences in travel time and less vehicles necessary to operate a PT-line.
In combination with the use of free PT lanes operational transport can use the same selective detection to receive priority at an intersection. Regarding the existing situation in 2010, the main benefits for operational transport are gained with special PT-lanes. Selective detection can only supply additional gain of time and can not solve problems at overloaded intersections.
Designissues
There are diverse systems which can provide the selective detection of PT and operational transport vehicles. To be able to use selective detection it is necessary to connect detection systems to the controllers. It is possible to make adjustments in currently used controllers but that will be relatively expensive. In general it is more cost-effective to select controllers with built in detection facilities. For this reason there are two cost-effective ways to implement detection systems:
1.wait till controllers have to be replaced due to end of economic life cycle of technical malfunctioning;
2.replace current controllers with new controllers fit for detections, old controllers can be used at new intersection (or renewed intersections) with less need for detection or can be used as a source of spare parts.
Examples of possible use of detection are given in the third interim report.
Note that PT-priority will not be automatically absolute priority. Absolute priority, with high PT-frequencies, like on most lines in Riga, lead to too much hindrance for other vehicles. Economic gain is there in two ways:
- need for less PT-vehicles to perform a schedule;
- improvement of reliability and travel speed of the public transport which will attract more passengers.
Different techniques can be used to detect vehicles with priority. The basic requirement for the system is the ability to send vehicle information to the controller like direction, line number and vehicle identification. On a longer distance this can be done by sending the information to a receiver with infrared or short distance radio. Bluetooth or RFID tags can be used as alternative at a short distance. For checking in, the system needs to provide accurate position data of the vehicle with a small measurement error. Checking out can be used but is not necessary for the commonly used fixed time traffic control strategy in Riga. The location of checking in should be checking in at a distance of 150 - 200 metres before the stop line.
Using infrared or other longer distance communication systems has the advantage that there is, besides the controller, no extra system necessary at the roadside. But it will be necessary to know the exact location of a bus, in order to prevent checking in too early (with negative impact on intersection capacity). This can be realised by using GPS and/or odometers. This means extra costs inside the vehicle, actually depending on the quality of the positioning system of the current on-board computers.
With systems based on Bluetooth or RFID-tag it is possible to detect a vehicle at a check-in point where a roadside system is placed. Disadvantage of these systems are the roadside units which result in extra costs. Regarding this it is expected that with carefully formulated requirements also new companies can develop a robust system, as a system integrator of parts of proven technology.
Measures included
1. Adaptive traffic control;
2. Upgrade of existing public transport stops.
Stages (short, medium, long term)
Short termSetting up an procurement procedure for implementation of PT-priority systems with assistance of an international specialised consultant;
after proven successful, further implementation of selective detection systems;
Medium/ Long termMaintenance and further development
Side effects
- Using selective detection gives opportunities for easy implementation of operational transport priority;
- Numerous priority requests at an intersection can lead to blocking the normal traffic flow (at peak hours).
Cost category
Basic indication of costs of equipment (based on Dutch experience with short distance radio):
- per intersection: EUR 5.000,--
- per vehicle: EUR 5.000,--
Investments in the first implementation period 2011-2017:
-setting up a international procurement procedure with assistance of a specialised consultant: EUR 100.000,--;
-implementation of selective priority systems at approximately 100 intersections and 160 vehicles: EUR 1.500.000,-- (major PT lines)
Note: the investments in the first project implementation period are relatively high. This is due to the situation that actual standards for equipment (e.g. on-board computers with an automatic positioning system) will be more usual after this period. In the first period investments have to include (partial) update or purchase of systems to meet the actual standards.
Stakeholders involved
Riga City Council Traffic Department, Rigas Satiksme.