Research Finds Spikes Fail as Ramp Obstacle

Dear Traffic Talk:

What happened to the excellent idea that was put forth many years ago of sharp spikes to make the tires unusable if the car attempted to enter a freeway offramp?

Rosalie Wits

Woodland Hills

Dear Rosalie:

According to Caltrans spokeswoman Pat Reid, although many people have suggested using some kind of tire slashing device on the exits, driving tests have shown the spikes would not work on vehicles traveling more than 15 miles per hour.

According to some of Caltrans findings:

1. Less than half of the vehicles tested were disabled by the spikes.

2. Those tires most damaged still took 10 to 30 seconds to go flat, which was still enough time to enter the freeway.

3. Tires bent and broke spikes, leaving them to puncture or damage tires of right-of-way vehicles.

4. In addition, at 30 mph, right-of-way drivers could not tell which way the spikes were pointing. This could cause more panic stops by right-of-way drivers than by wrong-way drivers.

But Reid added that even if the spikes worked perfectly, the problem would only be half solved.

Caltrans studies show that half of wrong-way moves are the result of deliberate U-turns and less than 50% are entries from the offramp.

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Dear Traffic Talk:

The junction of the Ventura and San Diego freeways is the major source of congestion in the Valley freeway system.

The major source of the bottleneck is the Haskell offramp just west of the interchange.

Northbound cars from the San Diego Freeway moving to the westbound Ventura Freeway must cross three lanes to exit here.

Not only does this disrupt the westbound lanes but it’s also potentially dangerous.

Southbound cars from the San Diego Freeway transitioning to the Ventura Freeway west must immediately move into the second lane or they will be forced to exit at Haskell.

This causes the San Diego Freeway to back up to Burbank Boulevard at all hours.

All of this activity slows the westbound Ventura Freeway no matter which way the lane is used all the way back to Laurel Canyon at rush hour.

The Haskell offramp serves a very small, exclusive neighborhood bounded by the San Diego Freeway to the east, Hayvenhurst Avenue to the west and Ventura Boulevard to the north.

This relatively lightly used offramp is a great convenience for few and a great inconvenience for many.

If the offramp were closed, cars could exit at Hayvenhurst Avenue without undue hardship.

Elia Richard Morris

Canoga Park

Dear Elia:

Pat Reid of Caltrans said that engineers are aware of the congestion problem at the interchange and are considering widening the northbound Ventura Freeway through the interchange to allow more time to merge.

However, Reid noted, no decision has been made about closing the ramp on Haskell Avenue.

Caltrans engineers also have to consult with the Los Angeles Department of Transportation about any plans that could affect traffic on a city street, according to Reid.

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