They do things differently in Texas, and that includes roundabouts. In Allen, Texas, officials built a unique teardrop roundabout interchange that serves as a gateway from U.S. Route 75.
The project rounds out our list of the year’s top roads because of its creativity and overall success.
Chris Flanigan, professional engineer for Allen’s engineering department said this recognition is rewarding for those who worked on the project.
“As a signature project for the community, on our namesake roadway, it is especially rewarding to learn that recognition through Roads & Bridges Top 10 program will promote the project for a wider audience to appreciate,” he said.
Allen city officials were concerned about safety and accessibility, both of which roundabouts are proven to enhance, but they also wanted to create a sense of identity for the community — apart from others along the highway.
The project did just that, and in its final form, the reconstructed interchange defies the school-of-thought that some engineers hold that beauty and infrastructure must be mutually exclusive.
The project accounts for the needs of motorists while also improving upon the safety for pedestrians, bridging the two sides of the community across an otherwise intimidating highway barrier. The project also provides connectivity to Rolling Hills Park.
The all-way stop intersections were transitioned to the roundabout configuration through four phases of construction.
During the first phase, a bridge was converted from three lanes of traffic, with one through lane and one turn lane in each direction, sidewalks on both sides. Sidewalks were rehabilitated to provide a widened trail on one side and limit pedestrian conflict points with vehicular traffic.
The teardrop roundabout configuration was completed in the next three phases, with a new raised median and mix-use trail on one side.
Transitioning from an all-way stop across an overpass to new travel patterns can create driver confusion. To make it easier for drivers, traffic was maintained in all directions with the use of temporary paving, temporary widening, and multiple traffic shifts.
The design team faced several challenges. They minimized environmental impact on residents by working within the existing sound wall footprint, and they worked within the existing right-of way. Despite these hurdles, the project finished on time and is now integral to the overall image, economic vibrancy, and cultural development for commuters and residents of the area. RB
Project Name: Allen Drive Roundabouts
Project Location: Allen, Texas
Owners: City of Allen
Contractors: The Fain Group
Cost: $3.5 Million
Length: 3140 ft
Completion Date: October 2022