Traffic Lights On Freeway Ramps Are Probably Making Your Commute Faster

Traffic comes to a stand still on the northbound and the southbound lanes of the Interstate 405 freeway near Los Angeles International Aiprort (Kevork Djansezian/Getty Images)

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For those of us who learned to drive on freeways without on-ramp traffic lights, the first encounter with one can be quite jarring. Instead of slamming on the gas until you've successfully merged with other cars going 65 mph, you're expected to slow down, stop and then attempt to politely zipper your way through four lanes of speeding vehicles who don't particularly want to let you in.

It just doesn't seem to make sense, at least not at first. And reader Jillian Stewart, hailing from Texas, was as flummoxed as the rest of us.

"Where did the traffic lights to merge come from, and do they help?" she asked LAist. "We got by in Texas without them and have similar heavy traffic."

An excellent question, Jillian, and one we've looked into for you.

According to the Press Enterprise, those traffic lights — called ramp meters — were first introduced in the United States in Chicago on the Eisenhower Expressway in 1963. In Los Angeles, the first ramp meter appeared on a Labor Day Weekend in the mid-1960s, according to Homar Noroozi, a principal engineer at the California Department of Transportation.

The meter, which was experimental, was placed on the connector between State Route 14 going southbound and the 5 Freeway going southbound. It was a success, so on Apr. 11, 1967, Caltrans installed the city's first two permanent ramp meters. They were located on the northbound entrances to the 101 Freeway at Sunset Boulevard and Hollywood Boulevard.

"The project was successful in relieving congestion on the freeway mainline without seriously affecting surface street operations," said Noroozi in an email. "It was estimated that freeway delay was reduced by about 75%."

Today, there are approximately 1,040 ramp meters in L.A. As for whether they help, Noroozi said that "while it is somewhat difficult to explicitly quantify ramp metering benefits without a detailed study comparing before and after effects of ramp metering, metering has proven to be an effective traffic operations tool to maximize the efficiency of a corridor."

A report issued by the U.S. Department of Transportation in 2014 entitled Ramp Metering: A Proven, Cost-Effective Operational Strategy supports this belief, noting that ramp meters reduce congestion and collisions, and decrease vehicle emissions.

And a four-month study conducted in Minneapolis/St. Paul in early 2000 bore this out. During the course of the research, ramp meters were turned on for a period of time then turned off. The results demonstrated a 22% reduction in travel time, a 26% reduction in collisions and a 7-mph increase in speed when meters were turned on.

Noroozi didn't say whether there were immediate plans for more ramp meters in the city, but it looks like they're here to stay — and that they're probably making us both safer and faster.