How Traffic Signals Are Timed Is a Matter of Priority

Dear Street Smart:

I moved to Ventura two years ago and have been trying to understand the sequencing of the traffic signals ever since.

At many intersections, the timing doesn’t seem to permit the even flow of traffic in any direction and the time sequence seems unusually long.

One intersection that seems particularly illogical is Johnson Drive and Telephone Road.

At many times during the day, all traffic at the intersection is at a stop in all four directions (including left-turn lanes on Telephone and all lanes on Johnson).

These lights obviously can be demand-controlled, since they sequence differently in the early morning and late-night hours and, it seems, on weekends.

James M. Crosser, Ventura

Dear Reader:

“It’s the same old question that comes up over and over again,” traffic engineer Nazir Lalani says. “Why can’t I have a green light when I get to an intersection?”

The reason, he says, is simple. When it comes to traffic flow, the needs of the individual are secondary to the greater good of moving the most traffic as expeditiously as possible.

In the case of Telephone Road and Johnson Drive, that means traffic on Telephone, by far the busier street, is given priority over cars on Johnson.

Signals on Telephone are synchronized from Petit Avenue to Main Street.

On weekdays between 7 a.m. and 8 p.m., the lights operate on a 110-second cycle. From 8 p.m. to 9:30 p.m. the cycle drops to 100 seconds.

The rest of the time and on weekends, the lights operate on demand--when traffic nears the intersection, it triggers a signal change.

At no time during any of these cycles is all traffic at a complete standstill, Lalani says.

On-demand signal changes would not work during peak traffic hours, he says, because they would cause major backups on Telephone.

*

Dear Street Smart:

I’m writing about the need for better traffic control at the intersection of Westlake Boulevard and Bridgegate Street.

In recent years, this intersection has gotten busier and busier with the development of the Lake Sherwood area.

As it is, people trying to get to and from work and school have a very difficult time getting through this intersection safely.

At the very least, the Westlake-Bridgegate intersection should be a four-way stop. A signal would be better.

I’ve tried calling the police, who refer me to the city’s traffic department, who refer me back to the police.

Maybe you can help us get some action here. I have five young children and am concerned about their lives.

Robin Dietz, Westlake Village

Dear Reader:

The city, too, is concerned about the safety of your children, along with your safety and that of the rest of the city’s residents, assistant traffic engineer Jeff Knowles says.

With that in mind, Knowles says that after studying the Westlake-Bridgegate intersection, the city has determined that it does not meet state and federal requirements for stop signs or a signal.

While there may seem to you to be a lot of traffic, he says, in the larger scheme of things it’s really not that bad.

Knowles suggests comparing the amount of traffic at Bridgegate with that on the nearby intersection of Potrero Road and Westlake Boulevard.

About 5,200 vehicles a day pass through that intersection, which has stop signs on Potrero, but none on Westlake.

There are also stop signs on Bridgegate where it intersects with Westlake. About 3,500 vehicles a day pass through that intersection.

“There just isn’t enough traffic coming from Bridgegate to warrant more traffic control,” he says.

He also urges you to keep in mind that stop signs and signals sometimes increase the accident rate at an intersection.

“We have to be very careful to make sure we’re not just going to make things worse,” Knowles says.

*

Dear Street Smart:

In your Sept. 5 column, you mention that car-pool lanes are being added to the Simi Valley Freeway and that these lanes will increase the freeway capacity by 11,500 people.

True.

The issue, however, is to reduce the number of vehicles on the freeway, therefore reducing air pollution.

The goal is not necessarily to increase the number of vehicles or people, but to rearrange them and improve the air quality at the same time.

Dirck Meengs, Thousand Oaks

Dear Reader:

Right you are.

The $22.4-million project to add 12 miles of car-pool lanes to the Simi Valley Freeway is designed not only to add more space but also to get cars off the road.

“The central concept in the (car-pool lane) program is moving more people rather than more cars,” a Caltrans spokeswoman says. “Some (car-pool lanes) carry up to 50% of the people carried on the entire freeway.”

The project, expected to begin within the next few weeks, will stretch from the Golden State Freeway to just west of the Ventura County line.

BRIDGE DEMOLITION

Starting today, Caltrans is scheduled to shut down portions of the Santa Paula Freeway to tear down the old Kimball Road bridge.

The westbound freeway will be closed from 9 p.m. today until 5 a.m. Tuesday between Wells Road and Victoria Avenue.

The eastbound freeway will be closed from 9 p.m. Tuesday until 5 a.m. Wednesday.