The payback period for expansion of an adaptive signal control system in Toronto, Canada was estimated at less than two years.
Modernization of the City’s Main Traffic Signal System (MTSS)
Toronto embarked on a Communications Reconfiguration Project (the COM Project) designed to reduce traffic control system communications costs by approximately 60 percent to 70 percent. The network wide system reconfiguration involved approximately 1850 signalized intersections connected to approximately 130 specially developed communication multiplexers designed to connect the Main Traffic Signal System (MTSS) and advanced adaptive control systems (SCOOT) with the central computers via high speed circuits.
The reconfigured communication system design pivoted on the application of central computers and software for the multiplexing/demultiplexing logic. This eliminated the requirement of costly annual system maintenance contracts.
Deployment of a SCOOT Signal System in Toronto
SCOOT (Split Cycle Offset Optimization Technique) was an adaptive signal control system that quickly updated signal timings to meet the needs of changing traffic volumes and patterns. This system yielded a number of benefits such as reductions in travel time, number of stops, queuing, fuel consumption, and air pollution emissions.
Toronto conducted a demonstration project to compare SCOOT to fixed (i.e., pre-determined) signal timing control plans. The results were summarized as follows:
- Traffic Flow Speeds--Increased 3 to 16 percent.
- Left Turn Violations--Reduced 71 percent.
- Rear-end Conflicts--Reduced 24 percent.
- Ramp Queues--Reduced 14 percent.
- Intersection Stop--Reduced 18 to 29 percent.
- Intersection Delays--Reduced 10 to 42 percent.
- Left Turn Delays--Reduced 0 to 35 percent.
- Vehicle Delay--Reduced 6 to 26 percent.
- Vehicle Stops--Reduced 10 to 31 percent.
- Vehicle Travel Time--Reduced 6 to 11 percent.
- Pollution Emissions--Reduced 3 to 6 percent.
- Fuel Consumption--Reduced 4 to 7 percent.
Based on the positive results of SCOOT, Toronto expanded the system to control approximately 250 additional signalized intersections. The payback period for the expansion project was estimated at less than two years.
ITS Technology Meeting Municipal Needs - The Toronto Experience
Author: Greenough and Kelman
Published By: Paper presented at the 6th World Congress Conference on ITS. Toronto, Canada
Source Date: 8-12 November 1999
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traffic signals, adaptive signals