Ramp Spikes Raise Thorny Safety Issues

Dear Traffic Talk:

Whatever happened to the excellent idea put forth years ago to install sharp spikes to deflate tires if a car tries to enter a freeway exit ramp?

Rosalie Witts

Woodland Hills

Dear Rosalie:

Caltrans conducted research geared at developing more effective signs, pavement markings and devices to prevent drivers from entering freeway offramps. The spike has been a frequent suggestion, said Pat Reid, a spokeswoman for the agency.

However, studies have shown that the spike is not effective against vehicles traveling faster than 15 mph.

Findings include:

* Less than half the vehicles tested were disabled by the spikes.

* The most heavily damaged tires still took between 10 and 30 seconds to cause the vehicle to stop.

* In some cases, the tires broke the spikes or bent them, leaving them in position to damage the tires of right-way vehicles.

Also, motorists coming off the ramp at 30 mph could not tell which way the spikes were pointing. This could cause more panic stops by right-way drivers than by wrong-way ones.

Reid said the studies also show that half the wrong-way moves on the freeway are the result of U-turns, not offramp entries.

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Dear Traffic Talk:

I have observed the absence of a freeway onramp sign on westbound Foothill Boulevard in Lake View Terrace just east of the Wheatland Avenue onramp.

If someone is driving west on Foothill, parallel to the Foothill Freeway, there is no ramp sign to advise the driver of the entrance to the westbound Foothill Freeway.

Can this situation be corrected?

Nancy Howard

Studio City

Dear Nancy:

Freeway guide signs are indeed missing at that location, according to authorities.

Foothill Boulevard is under the jurisdiction of the city of Los Angeles, said Caltrans spokeswoman Reid.

She said Caltrans has notified city engineers, who have indicated that the signs will be installed soon.

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Dear Traffic Talk:

Please clarify usage of carpool lanes, as there is much abuse.

Are empty buses, empty vans and lone motorcycle riders OK? Can people exit anywhere since the double yellow line is accompanied by a white line?

Dennis Marks

Chatsworth

Dear Dennis:

Two ways to learn about carpool lane use are purchasing the California Vehicle Code for $3 at any DMV location or calling the local office of the California Highway Patrol.

Specifically, private vans and buses with only the driver are not allowed in the carpool lanes. However, a law that will take effect Jan. 1 will allow public transportation buses with only the driver to use the lanes, said Sgt. Ernie Garcia of the California Highway Patrol.

Motorcycle riders are allowed in the lanes. Meanwhile, the white line alongside the double-yellow lines is simply to differentiate the freeway carpool lanes buffer markings from the “no-passing” zones on two-lane highways.

People can exit the lanes only at single broken white lines.

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