US 18/151 Freeway Conversion Study - Need/purpose

Experience around the state has demonstrated that highways can deteriorate quickly in terms of reduced operations and safety as land development changes occur near a highway.
Of greatest concern to WisDOT are the at-grade intersections along US 18/151. As traffic increases over time (see Traffic counts maps), it will become increasingly difficult to turn on, off and/or cross the highway in a safe manner, and the potential for crashes will increase.

The purpose of this study is to develop a long-term highway plan for converting this portion of US 18/151 to a freeway.
The study will result in a plan for the eventual removal of all direct access by existing local roads and driveways onto US 18/151.
When construction of all plan elements is completed, access to US 18/151 will be at highway interchanges only. Local access to the interchanges will be facilitated by new grade separated crossings over or under US 18/151 and by adding to and improving the existing local road system.
This will allow both the local communities and property owners adjacent to the corridor to adequately plan for their futures.
It is important to note that this study is focusing on identifying and planning for long-term access to and from the corridor, not adding additional capacity (travel lanes) for most of the corridor.
The study is proposing to add an auxiliary lane, between County G and County MV, in Dane County, to accommodate the travelers who use US 18/151 to travel between these two points. This is a relatively large movement of traffic and the auxiliary lane will enhance safety.
The changes in access proposed in the plan are expected to be made in five or more sections over a 15-20 year period, as funding is available and construction of each section of the corridor rises high enough on the list of statewide priority. The timing of building the improvements at specific locations will be based primarily upon safety considerations.