Carver County staff propose uniform turn-lane policy to guide development and improve safety

Carver County staff presented a draft turn-lane warrant and design policy at a county work session, proposing consistent rules for when turn lanes should be added or modified on county highways and how long and offset lanes should be designed.

Whitney Schroeder, traffic engineer at Carver County, said the draft moves the county away from a “one-size-fits-all” reliance on MnDOT guidance and traffic operations reports and toward a policy that accounts for safety, speed and truck volumes. “We are going to be using the 20-year projected traffic volumes for a lot of the volume warrants and thresholds,” Schroeder said, and the policy uses hourly turning-movement thresholds so developers’ peak-hour analyses can be applied directly.

The policy would apply to most county projects other than simple resurfacing or seal-coat work and distinguishes uncontrolled approaches (two-way stop) from controlled intersections (signals or four-way stops). For uncontrolled intersections the draft uses speed and a relationship between turning volumes and opposing through volumes; the county would treat 50 mph and above as high-speed and 45 mph or lower as low-speed. For controlled intersections the guidance calls for capacity and crash-history review and consideration…