About the Project
Various Locations State of Missouri
CBB has performed numerous signal timing improvement projects during the last 15 years for the Missouri Department of Transportation (MoDOT). This program involves the re‐optimization of signal systems within the Saint Louis District beginning with pre‐travel time measurements, intersection delay measurements, manual turning movement counts, 24‐hour hose counts for one continuous week, and an extensive field investigation of the project corridor. Clearance intervals are verified for MUTCD compliance and flashing yellow arrow left-turn locations are analyzed for time of time operation. Timing plans (including diversion plans) are then developed using the Synchro software package and implemented. At this time, individual movement splits and intersection offsets are monitored, and field adjusted to fine‐tune progression through the corridor to the satisfaction of MoDOT. CBB utilizes state-of-the-art travel time and signal performance measure technology to ensure new signal timing plans are customized for each individual route. 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. Since 2006, CBB developed and installed new timing plans as part of 12 separate projects including 411 intersections – resulting in average reductions in travel times of 13% and 12% in the morning and afternoon peak periods, respectively. These reductions produced $12,290,416 in annual fuel cost savings for motorists, as well as decreased vehicle emissions by 2,935,407 lbs. per year.
