Doors in Sound Walls Give Workers Entree to Repairs

Dear Street Smart:

On the Riverside Freeway between Harbor Boulevard and Euclid Street, workers just finished putting up a sound wall. I’ve noticed that there are little doors in the sound wall every 100 yards or so. I’ve also seen those doors in many sound walls throughout Los Angeles and Orange County freeways. What is the purpose of these doors?

Mario Luna, Anaheim

The doors in the sound walls provide access for Caltrans maintenance personnel, said Al Fisher, chief of environmental planning for Caltrans. The access allows workers to make repairs to the wall when needed and to get to the other side of the wall to clear away debris and weeds without having to cross private property, he said.

Not all of the 23.2 miles of sound walls that currently exist in Orange County are equipped with doors, Fisher said. The walls are built on Caltrans property and doors are installed only in areas where access to the back side of a wall would be difficult without them, Fisher said.

In Southern California the walls are generally constructed of concrete block, although statewide there are walls made of wood and other materials that effectively buffer freeway noise, Fisher said. Nothing is kept inside the walls.

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Dear Street Smart:

I would like to know why a right-turn arrow cannot be added for eastbound traffic from McFadden Avenue turning south onto Gothard Street in Huntington Beach when the signal is green for northbound Gothard traffic.

The signal on Vermont Street south is a separate signal so it has no bearing on the northbound Gothard traffic.

Barbara Atwood, Westminster

The intersection you cite is not a traditional four-way intersection, but is split so that the streets don’t line up, said Jim Otterson, city traffic engineer for Huntington Beach. Gothard makes up the south section and Vermont makes up the north, but Vermont is positioned farther west, he said.

If eastbound McFadden traffic were permitted to make a right turn south onto Gothard, it would create a conflict with the motorists traveling south on Vermont, Otterson said. The result would be that two cars would be trying to take up the same space at the same time, he said.

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Dear Street Smart:

There is something about left-turn lanes that has puzzled me for many years. Why are the sensors placed so close to the intersection?

Drivers know this, and accelerate when entering the lane, either to beat a red arrow or to activate a green arrow. I saw an accident in Long Beach recently where two drivers entered a left-turn lane with a green arrow in their favor. They both accelerated, but the green arrow turned yellow almost immediately. The first car decided to stop, and you can imagine what happened.

If the sensors were further back in the lane, even at the entrance, drivers would be less inclined to floor it and accidents might be avoided. Of course, a sensor would still have to be located at the intersection to pick up cars that move into the lane at the last moment.

David Carlberg, Huntington Beach

Left-turn signals were never intended to stay on for any great length of time because drivers making left turns block through traffic, said Otterson, the Huntington Beach city traffic engineer. Left-turn signals are designed to stay on only when there is a left-turn demand, he said.

“We put (the sensors) at an intersection to sense the presence of someone in the left-turn pocket, that someone is there waiting, not approaching,” Otterson said. “Generally at most intersections, more people are going through than making left turns.

“We try to minimize all delays for motorists, so we give more green time for through traffic, just as there are more through lanes than left-turn lanes.”