Lane Widening Traffic Analysis

IMPROVING TRAFFIC SAFETY ONE LANE AT A TIME

The City of Birmingham, the City of Bloomfield Hills and the Road Commission for Oakland County proposed to construct a center lane for left turns on Quarton at Chesterfield Avenue. The safety improvement plan, however, raised resident concerns that the addition of a left turn lane would promote more traffic on Chesterfield.

The City of Birmingham hired F&V to perform a traffic analysis to see what impact the improvement plan would have on the existing traffic movements at this intersection. The study included data collection, modeling of the adjacent road network, analysis of traffic operations, safety and crash analysis and identification of traffic impacts of the proposed turn lane. This traffic count information along with the other related intersection geometry was analyzed to determine the vehicle delays, level of service and vehicular queues for the two (existing and future) geometric scenarios.

The analysis determined the center lane for left turns would not increase traffic and would significantly reduce traffic queues in the through traffic stream. In addition, the reduction in traffic queues would reduce nearly 65 percent of the crashes that were occurring at this intersection. Construction of the left turns was completed in 2015 and residents have already noticed the improvement.