Ramp Metering

How They Work

The meters work and look similar to traffic signals. Drivers must consider and obey them as they would other traffic signals. Specifically:

• A red light means stop, a green light means go.
• A typical meter cycle is two seconds of green and two to ten seconds of red. The wait on the ramp is usually about one minute.
• Flashing yellow lights located near the ramp entrance alert motorists that the meter is on and that they should be prepared to stop.
• Signs and pavement markings indicate where to stop and how to proceed.
• Depending on the location, ramp meters on I-435 will have one or two lanes. Two lane ramps will use a “staggered release” where the left releases the vehicle first and then as its signal turns red, the right signal turns green.
• Most ramp meters permit one vehicle to proceed per green light, but some high traffic ramps will allow two vehicles to pass per green light. Signs before and at the signal will indicate the number of cars permitted per green light.
• Ramp meter signals are equipped with adequate shoulder width for emergency vehicle bypass.

The meters monitor and control traffic entering the freeway during the morning and afternoon commutes. They are designed to turn off if the number of cars waiting on the ramp grows to the point where they back up onto city streets, and turn back on once the ramp queue is reduced to a reasonable level.

By controlling the flow of cars, ramp meters actually allow more cars to use the freeway.

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