Why are meters flashing yellow when the mainline is stop and go?
A. During those hours when ramp meters can be activated (6:30 to 8:30 in the morning and 3:30 to 5:30 in the evening), they will do so based on volume/congestion thresholds which when met trigger the start-up of a meter. These thresholds are based on the number of vehicles entering the freeway in a particular area (or zone) and the number of vehicles already on the freeway in that same zone. (To help it better manage the freeway network, Mn/DOT has divided it into 93 zones, each between three and five miles long). Under the recently enacted ramp meter modifications, when a zone becomes so congested that metering would no longer be helpful to the efficient movement of traffic through it, the zones meters will simply continue to flash yellow. If congestion thresholds in a specific zone are met prior to the start of ramp meter operating hours, the meters in that zone will continue to flash yellow throughout the rush hour.
