Upper St. Clair Township

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The McLaughlin Run Roundabout Is Open

PennDOT District 11 has announced the opening of the McLaughlin Run Road roundabout project.

This $4.67 million project converts the previously signalized McLaughlin Run Road and Lesnett/McMillan Road intersection into a free-flowing single-lane roundabout. Work includes the replacement of two structures, sidewalks, ADA curb cut ramp, lighting and pavement marking installation, guide rail and drainage improvements.

Crews will continue line painting and other miscellaneous work on the project with intermitted traffic stoppages of 15 minutes or less and single-lane restrictions with the assistance of flaggers as needed weekdays from 6 a.m. to 5 p.m. through late September. The overall work will conclude in early October 2022.

To help motorists navigate the newly constructed roundabout, PennDOT has created an informational video.

Roundabouts offer improved safety over other at-grade intersection forms primarily because there are fewer conflict points, slower speeds, and easier decision-making.

Geometrically designed to reduce vehicle speeds to generally 25 mph or less, roundabouts only consist of right turns. This significantly reduces the severity of crashes over those at traditional intersections. Crashes that do occur are typically low-speed, sideswipe crashes rather than high-speed T-bone collisions that can occur at traditional intersections, especially with left-turn movements. Roundabouts also improve pedestrian safety due to the slow speeds and by providing a media refuse area. This allows for two simple crossings of one-way traffic.

Roundabouts typically carry about 30 percent more vehicles than similarly sized signalized intersections during peak traffic conditions. During off-peak conditions, roundabouts cause almost no delay, unlike traffic signals which can cause delays to side streets and traffic turning left from the major street. The increased capacity and efficiency of roundabouts are due to the generally continuous slow-flowing nature of entering vehicles yielding to circulating vehicles rather than waiting for a signal to turn green. 

More information on this project can be found on PennDOT's District 11 website.