Office of Operations
photos of traffic merging onto congested highway, congestion in snowstorm, variable message sign, cargo, variable speed limit sign in a work zone, and a freeway at night
21st Century Operations Using 21st Century Technologies

Traffic Bottlenecks

Combating Bottlenecks


"SWARM"ing to relieve congestion with "adaptive" ramp metering.

Background: System Wide Adaptive Ramp Metering (SWARM) has been successfully tested on the highway network in the Los Angeles (L.A.) region and is ready to roll out to the most congested highways in the nation. Adaptive ramp metering is "smart" ramps that use detectors and algorithms to constantly, and most importantly, automatically, adjust the flow rate of merging vehicles at the subject ramps. Unlike normal ramp metering, which reacts to the demand of the ramp based on detectors only on the ramp, SWARM metering "talks" between the mainline detectors and the ramp detectors.

Bottleneck Project: I-210 will soon have the smartest (computer adaptive) ramp metering system in the nation; all of it controlled by the complex algorithms and operators at the CALTRANS District 7 traffic operations center in L.A.