What was the rationale for narrowing Big Bend in Webster Groves between Berry and Elm from 4 lanes to two lanes?
Are there any plans to rehab or remove the median planters on Tucker between Lafayette and Pine? Most are crumbling or full of weeds. Having three lanes each way would certainly improve traffic flow.
This modification is part of an ultimate plan involving Webster Groves, to carry two lanes through the Crossroads District in order to provide better separation between motorists traveling along Big Bend Boulevard and pedestrians using the sidewalk along Big Bend Boulevard in the Crossroads District. Those changes will be made at a future time when that section of Big Bend Boulevard is resurfaced.
Big Bend Boulevard between Berry Road and Gray Avenue was converted from four narrow travel lanes into two travel lanes with a center turn lane. The center turn lane is a safety feature that allows motorists waiting to make a left turn onto any of the many other side streets or driveways to do so without stopping in a through lane, including providing for exclusive left turn lanes at the Rock Hill Road traffic signal. It is common practice to separate left turns from through lanes at traffic signals where possible. The change in striping also provides wider lanes, which gives more room for motorists.
According to the Federal Highway Administration, a four lane to three lane conversion increases safety by reducing the number of conflict points by half and by removing left turning vehicles from the stream of traffic. Conflict points are any point where the paths of two through or turning vehicles conflict with each other. The probability of a crash increases with the number of conflict points. In other words, there are fewer opportunities for vehicles to conflict with each other. Therefore, designs that reduce conflict points are generally safer. Other safety and operational benefits include easier crossings for motorists and pedestrians and better sight lines. David Wrone, St. Louis County
On roads with frequent left turns at driveways and minor intersections, such as Big Bend Boulevard between Berry Road and Gray Avenue, reducing the number of through lanes by half in order to provide a continuous left turn lane does not reduce the amount of traffic the roadway can carry by half. This is due to smoother traffic flow resulting from removing left turning vehicles from the flow of through traffic. This turning traffic effectively causes a four lane road to operate similarly to a three lane road by blocking one of the through lanes.
Prior to implementing a reduction in lanes as part of a resurfacing project, the amount of traffic on the road is taken into consideration. Case studies have shown roads with daily traffic less than 17,500 vehicles are good candidates for four lane to three lane road diets. The traffic levels on Big Bend Boulevard between Berry Road and Gray Avenue are well below this threshold. David Wrone, St. Louis County Highway Department