Flex Lane on US 12 (Madison Beltline)

Project location | Project overview | Schedule | Traffic impacts/detours | ​Contact information

​​Project location

US 12/18 (Madison Beltline), Whitney Way to Interstate 39/90 - Dane County

Image of map showing project start and end points 

Project overview

The Wisconsin Department of Transportation (WisDOT) will make the following improvements on the Madison Beltline (US 12) between the Whitney Way exit and I-39/90:

  • Resurface to address deteriorating pavement;
  • Improve existing drainage deficiencies;
  • Replace the existing median barrier wall; and
  • Upgrade Beltline median shoulders to be used part-time as travel lanes.

Upgrading the shoulders for through travel is a practice known as part-time shoulder use, which is branded in Wisconsin as the Flex Lane. The shoulder travel lanes would typically be open during peak periods to safely and efficiently improve travel reliability between Whitney Way and the Interstate.

What is Flex Lane or Part-time Shoulder Use?

Part-time Shoulder Use is recognized as a safe, sustainable and reliable way to alleviate congestion. It is already used in at least 17 other states. The concept allows vehicle traffic on the paved shoulders during peak travel times. Changeable message signs located above the lanes are used to indicate when the shoulder is available for use.​

​This project is built within the existing footprint of the Madison Beltline.​



  • March​ 2021 – Flex Lane construction begins
  • December 2021 – Construction completion; anticipated opening in late 2021 or early 2022

Construction traffic impacts

  • Daily single lane closures from 9 a.m. to 2 p.m. Monday through Thursday and 9 a.m. to 3 p.m. Sundays.
    • ​​Plan ahead for delays and allow extra time to reach your destination.
  • Off-peak ramp closures at interchanges between I-39/90 and Whitney Way.
  • Nightly lane closures from 6:30 p.m. to 6 a.m. Monday through Friday.​

Contact information

WisDOT welcomes the opportunity to share and present this information to your organization or association. Please contact the project staff listed below to share project materials and/or schedule a virtual presentation. Thank you for your interest in this project.

Brandon Lamers​, P.E.
Project Supervisor
(608) 246-3852

Steven Theisen
Communications Manager
(608) 884-1230