Madison Beltline Flex Lane

HNTB has led the roadway, structures and overall design on Madison’s busiest highway, the Madison Beltline, that carries USH 12, 14, 18 and 151 along the west and south sides of Madison. Known for its congestion during peak traffic periods, the roadway’s existing concrete pavement, median concrete barrier and storm sewer were deteriorating, and the roadway required rehabilitation to extend its useful life. The Wisconsin Department of Transportation (WisDOT) determined that an asphalt overlay along the eastern-most nine miles would prolong the pavement life and provide for restriping of lanes to incorporate a part-time shoulder lane to improve traffic operations. These decisions result in extra added benefits at a much smaller cost compared to expansion alternatives.

Dynamic part-time shoulder use, branded in Wisconsin as the Flex Lane, is recognized as a safe and sustainable way to alleviate congestion. Various forms of part-time shoulder use are in place in approximately 17 states. However, this is the first application in Wisconsin, providing a cost-effective way to improve traffic operations with less environmental impact. The part-time shoulder lane is controlled with dynamic lane control signs supplemented with various message signs to help traffic move safely and efficiently. Implementation of part-time shoulder use increases the level of service and minimizes recurring delays during peak hours. HNTB worked closely with various WisDOT departments including design, structures, maintenance, signing, environmental and traffic management center (TMC) staff. Additional coordination with local stakeholders including law enforcement and county maintenance staff was critical to develop safe operation procedures for the Flex Lane. These repairs and upgrades to the pavement, barrier wall and drainage infrastructure will maintain the life of the roadway corridor for the next 10-15 years.