Wednesday, November 23, 2016

In the Golden State, a Golden Anniversary for Ramp Meters

Ramp metering in use on northbound Interstate 405 in the city of Los Angeles.

Many drivers are familiar with ramp meters, widely used in California to control the flow of vehicles entering freeways. But few may know 2016 is an important anniversary of this cost-effective tool for smoother traffic.

Exactly 50 years ago, ramp meters made their California debut. In 1966 the Golden State’s first experiment with them took place in Los Angeles County in Caltrans District 7.

The next half-century showed the value of ramp meters in fighting gridlock and increasing average traffic speed. Now, almost 3,000 ramp meters are in use throughout California, according to Caltrans figures as of December 2015. Ten of the 12 Caltrans districts statewide operate ramp meters or anticipate doing so by 2025.

But in 1966 they were an innovative idea, introduced only three years earlier in Chicago and then in the Detroit area.

District 7 saw ramp metering as a possible answer to a bottleneck on Interstate 5 (Golden State Freeway) at the northern edge of Los Angeles.

“It all began on the last day of the Memorial Day weekend at the junction of Routes 5 and 14, in the foothills in northern Los Angeles. Recreation traffic returning home from the holiday jammed the interchange between these two routes, resulting in ‘intolerable’ delay. It was decided that something would have to be done to prevent a repeat of this type of congestion,” Stuart Harvey, former deputy director of Caltrans District 11 in San Diego, wrote in a 1990 short history of ramp metering in the state.

So District 7, through its newly created Freeway Operations Department, crafted a plan it unveiled at the 5/14 junction on the 1966 Labor Day holiday.

“Traffic Operations staff decided to try regulating the flow onto Route 5 with a portable traffic signal under manual control,” Harvey wrote. “The actual control mechanism which was employed might be considered primitive by modern standards.” But it worked and was remarkably effective.

Ramp metering on northbound U.S. Highway 101 in Thousand Oaks.

Indeed, the experiment “was very successful in controlling congestion and delay, and it was decided to refine the technique,” Harvey added.

“On the next holiday, Christmas Monday, the same basic method was used, except that the portable traffic signal was programmed to cycle automatically and the cycle length was manually adjusted to account for changing conditions on the freeway.”

The tryout was judged a complete success, and District 7 made plans for another ramp meter audition in the heart of Hollywood.

Only months later, on April 11, 1967, California's first two permanent fixed-time ramp meters were activated on the northbound U.S. Highway 101 (Hollywood Freeway) at Sunset Boulevard, with corresponding northbound ramp closures at Hollywood Boulevard from 4 to 6 p.m.

Before throwing the switch, however, District 7 worked closely with the city of Los Angeles to prepare the public for the historic step.

“There was a grave concern on the part of the community, particularly the Hollywood Chamber of Commerce, about the impacts of ramp metering,” William E. Schaefer, former deputy director of project development and chief engineer of Caltrans, said in an oral history interview recorded shortly before his retirement in 1990. Schaefer was design engineer in District 7 during the introduction of ramp metering.

“It was pretty carefully planned out. We spent a number of meetings with the Hollywood Chamber of Commerce convincing them that it was worth giving it a try,” Schaefer said.

“That first night, I was comfortable it would work,” Schaefer recalled. “I took some of the officers of the chamber with me in my car to go around through the project to show them that it worked. And it worked beautifully.”

The project successfully relieved congestion on the freeway mainline without seriously affecting surface street operations. Freeway delay was reduced by about 75 percent.

“In that early primitive stage,” Schaefer said, “we operated the metering with a little button with a guy behind the bushes. So we didn’t have any sophisticated equipment. We simply had a traffic light with some power and a button to change the signals. And then we put in a normal, little old fixed-time controller. It was a very, very primitive system but it really worked great. And from that we moved on to a lot of other projects.”

Today, most ramp meters in California respond automatically to freeway traffic conditions monitored by inductive loop detectors in the roadway. When the freeway flows freely, more cars are allowed to enter.

Systems also can use centralized monitoring of traffic conditions to help determine the metering rates for all of the ramp meters along a corridor.

The objective, just as 50 years ago, is to limit freeway congestion. Studies show the success of ramp meters in promoting more efficient overall operation of freeways with higher average speeds and fewer collisions and delays.

California’s highway system has about 2,954 meters as of December 2015. District 7 has about 1,024 metering locations, including 28 freeway-to-freeway connector meters, making it the largest ramp metering district in the state and nation.

Monday, November 21, 2016

Caltrans Deploys Its First Hydrogen Fuel Cell Cars

Caltrans has recently added 20 new hydrogen fuel cell vehicles to its fleet to help the department meet the state’s goal of reducing greenhouse gas emissions. Those vehicles will be deployed in various locations throughout the state, but they were all customized for Caltrans' use at Shop 7 in Sylmar.

In the video below, District 7 Highway Equipment Superintendent Brian Valenti explains how his team customized the vehicles, and then we head to La Canada for a lesson on how to fuel up a hydrogen fuel cell car.


Monday, November 7, 2016

Paramount Blvd. Bridge Restoration: 55-hour Ramp Closures

Caltrans will close the westbound SR-60 on- and off-ramps, and the eastbound off-ramp 10 p.m. Friday, November 18 to 5 a.m. Monday, November 21 as part of the Paramount Boulevard Bridge Restoration Project so that construction crews can repave the ramps.  

Motorists may experience delays and should consider alternate routes.
Caltrans is restoring of the Paramount Boulevard bridge above the Pomona Freeway (SR-60) by realigning and upgrading two cloverleaf ramps to current standards, constructing sidewalks, and adding pedestrian ramps that meet Americans With Disabilities Act standards. Additionally, three retaining walls will be constructed along the westbound on- and off-ramps, and along the westbound on-ramp near the intersection of Paramount Boulevard and Neil Armstrong Street. 

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Wednesday, November 2, 2016

Overhead Sign Structures for New Empire Ave Off-Ramp Going Up

Base of overhead sign structure located on Leland Way.

If northbound I-5 in Burbank is part of your daily commute, next week you'll notice a crane just north of Burbank Boulevard on the other side of the new soundwall. That crane will be used to install the overhead sign structures for the new Empire Avenue off-ramp and the Buena Vista Street off-ramp just north of there. The new Empire interchange won't open until 2018, but the sign structures are going up now.

The operation will take about a week and will not disrupt traffic on I-5. If you live on Leland Way, however, some street closures will be necessary to accommodate the crane and other equipment. Details below.

Upcoming work: Crews will install two new overhead freeway sign structures. The signs themselves will be positioned over I-5, but the structure bases are located on Leland way. (See map below.) Please note that these signs will have no lights—they'll have a highly-reflective coating instead.

Construction schedule: Sign structure installation, which will require a crane stationed on Leland Way, will occur the week of November 7-11, 2016. Crews will work primarily 7 a.m. to 4 p.m. Set-up work may begin earlier. Schedules are subject to change. 

Work location: Crews will work at two locations on Leland Way to install the overhead sign structures, one of which is at the south end of the street near the cul-de-sac, and the other is near University Avenue. (See map below.) Crews will work in one location at a time.

Why these signs are necessary: Caltrans is constructing a new full interchange at Empire Avenue. The overhead signs will direct motorists to the new northbound I-5 Empire Avenue exit and other exits.

Closures: For the safety of residents, motorists and the construction crew, street parking will be restricted when necessary to accommodate the operation. Please pay attention to signs. Flaggers will be on site to direct motorists. Access to homes and driveways will be maintained at all times.

Noise: There will be some construction noise, but it will not exceed levels permitted by federal, state and local regulations.

More information: Learn more about the I-5 Empire Project at Submit your email address to get project updates. Questions? Call us on the I-5 Info Line at (855) 454-6335 or send an email to