STH 54 and Maple Drive Intersection Roundabout

Background

The intersection of STH 54 and Maple Drive on the southside of Plover marks the highway’s transition from rural use to urban use. The speed limit near the intersection transitions from 55 mph to 30 mph when approached from the south; as a result, northbound vehicles typically decelerate through the intersection while southbound vehicles tend to accelerate. As an OSOW route in Wisconsin, roughly 19% of the 6,100 vehicles traveling on STH 54 each day are heavy trucks.

Approach

Having experienced a series of crashes within a short timeframe, the intersection reached a crash rate of 1.48 and was flagged for safety. The WisDOT North Central Region tasked Foth with identifying options to slow speeds and improve intersection safety.

Our team determined that the two-way stop control along Maple Drive was a contributing factor to the crashes. Numerous collisions were the result of stopped drivers having difficulty judging vehicle speeds along STH 54 and attempting left turning maneuvers. To address the issue, we developed two alternatives: a conventional intersection with traffic calming measures and additional turn lanes, as well as a modern, single-lane roundabout. After an extensive public information campaign, the roundabout was chosen as the preferred alternative.

Results

During design, three of the four approaches were given raised, divided medians with a curvilinear shape to reduce speeds. To accommodate heavy trucks, entrances were widened slightly and the truck apron on the central island was elongated. Colored pavement and curbing along the island deter smaller vehicles from using the truck apron. Pedestrian and bicycle facilities were added along STH 54, with grooved, reflective thermoplastic crosswalks and ADA compliant ramps on all approach legs. Lighting and storm sewer upgrades were also included.

The North Central Region submitted this project for the 2016 WisDOT Excellence in Highway Design—Best Urban Project by a Consultant/Municipality award.