Projects

Signal Coordination and Timing Projects (SCAT)

Signal Coordination and Timing Projects (SCAT)

CBB has worked with the Illinois Department of Transportation (IDOT) on this statewide signal timing improvement project during the last 20 years. CBB’s participation in this annual program has involved the re-optimization of signal systems within two groupings of IDOT’s districts (2-5 and 6-9). Each group’s project consists of approximately 8-10 individual signal systems per year. The optimization process begins with pre travel time measurements, intersection delay measurements, 12-hr manual turning movement counts on a typical weekday and Saturday, 24-hr hose counts for one continuous week, and an extensive field investigation of the project corridor.

Timing plans are then developed using the Synchro software package and submitted to IDOT for review in a preliminary letter report. This report consists of a brief documentation of the corridor recommendations, traffic volume summaries, Synchro reports with time-space diagrams, and a traffic event schedule.

Upon approval of the proposed timings, CBB meets with District signal engineers for the field implementation process.  Depending on each District’s preference, CBB either programs the controllers or IDOT’s local signal engineer programs them in advance.  CBB and IDOT’s signal engineer perform field observations during each peak period.  At this time, individual movement splits and intersection offsets will be monitored and field adjusted in order to fine-tune progression through the corridor to the satisfaction of IDOT’s signal engineer.

Once the plans have been finalized on-street, the travel time and intersection delay measurements are repeated to determine the benefits of the retiming efforts. A final report is then prepared that details the project, analysis procedures, and contains a comprehensive data appendices (consisting of turning movement counts, hose counts, time-volume graphs, existing and proposed Synchro reports, travel delay summaries, intersection delay summaries). This final document identifies improvements to the corridor in terms of annual reductions in fuel consumption costs and vehicle pollutant emissions.

Since 2005, CBB’s efforts for IDOT in their SCAT program have resulted in an average reduction in travel times of approximately 25% in both the morning and afternoon peak periods. By doing so, CBB’s timing plans have led to the reduction in fuel costs for motorists over the last 9 years of $9.3M and lowered vehicle emissions by 2.2M pounds – an average of $282K and 67K pounds per project!

Projects

The are no features that match your current filters. Add some features that meet your filter requirements and check again.

CBB 
12400 Olive Boulevard, Suite 430
St. Louis, MO 63141
314-878-6644
314-878-5876 (fax)