N. 14th and Superior Streets Roundabout
The City of Lincoln, Nebraska, retained MTJ Engineering to complete an in-service design review and provide recommendations to improve the very poor safety record of the recently opened roundabout located at the arterial intersection of N. 14th and Superior Streets.
MTJ Engineering’s review identified potential geometric and information processing challenges that drivers were facing at this roundabout. Areas were identified where drivers may become overloaded by driving demands or receiving conflicting information, which could result in drivers conducting important driving tasks in an improper fashion.
The review recommended changes that included:
- Lane reductions – based on operational analysis of revised design traffic flows, reduce to 2×1 roundabout.
- Implement standard (and oversized) lane-use signing and marking conventions vs. stylized “fish-hook” markings.
- Modify existing pedestrian signal to remove resting in green condition.
Four alternatives were planned, each with considerable reduction in conflict points (from 30 to 12 points in one alternative) without any loss of service. Ultimate plans were included for future expansion.
Results: 73% reduction in crashes.
See this article from the Lincoln Journal Star about how successful the recommendations and implementations have been.