The new Vernon Avenue & Highway 100 Interchange was designed to accommodate southbound access to Highway 100. The City already has approval from the Minnesota Department of Transportation and City Council to permanently close the “slip” ramp for safety reasons. Staff recently collected traffic information in the district to confirm design assumptions. Permanently closing the onramp is still supported by current and future traffic analysis.

Crash data on the ramp from January 1st, 2018, through December 31st, 2022 was analyzed using the MnDOT Crash Mapping Analysis Tool (MnCMAT2). The type and severity of the crashes were reviewed, and crash rates and critical rates were calculated. Crash rates are expressed as the number of crashes per million entering vehicles (MEV) at an intersection or along a segment. The critical crash rate is a statistical value that is unique to each intersection. It is based on vehicular exposure and the average crash rate for similar intersections or segments; a crash rate higher than the critical rates indicates a sustained crash problem.

The existing Eden Avenue entrance ramp to southbound TH 100 had 20 crashes during the 5-year review and has a crash rate that is 6-times the critical crash rate. The majority of these crashes, 85-percent, occurred at the merge point of the Eden Avenue ramp and the Vernon Avenue Ramp, prior to the merge with southbound TH 100. The existing merge provides approximately 250-feet of acceleration upstream of the merge and includes a yield condition with the Vernon spur. Without adequate distance to accelerate, vehicles enter the merge at low speeds and due to the yield condition frequently brake hard at the merge; this results in a high percentage of rear-end collisions on the entrance ramp at the yield location.