Real-time, real-world congestion management - Urban Traffic flow optimization

Location : Arlington County, Virginia, U.S.

The high public-visibility project focused on roadway system performance for a corridor of 25 signalized intersections in Arlington County. Project was completed over span of five business days.

Problem statement:

The project corridor began at S Joyce Street @Columubia Pike, through Bailey’s Crossroads interchange @ Columbia Pike. This section of corridor of Columbia Pike is intercepted by several other arterials. The corridor is two-lane in each direction with several bus-stops and left-turns preventing smooth traffic flow.  The corridor had not been updated with traffic flow management measures in a very long time. The project focussed on delay minimization.

Solving:

I conducted travel-time runs in the corridor for data collection on travel time, followed by delay studies as a measure of roadway system performance.

This was followed by creating the network model in Synchro. Onto this I loaded current tube-count volumes and traffic signal timings of 25 intersections. I analyzed flows, and optimized the network for reduced queuing and improved traffic flow i.e., reduced delay.

Resulting optimized signal-timings were taken to the corridor, and downloaded onto controllers located at each intersection at 0330h (i.e. 0330AM), well ahead of the morning peak period expected to begin by 0530h lasting a little past 0800h.

Through a combination of driving in the traffic and some on-ground observations, I observed the traffic flow and queuing during both AM and PM peak periods.

Signal timing of each intersection were then tweaked on-site directly through the controllers by the VDOT technicians, as they have jurisdiction over the controllers.

Project outcome was as desired - reduced queuing and reduced delay.

Image source: Personal project archives.