Nearly half of Los Angeles’ streets have speed limits based on outdated speed surveys, which has prevented Los Angeles police officers from using radar and laser devices to enforce rules against speeding. But that may change soon, city officials say.

Speed limits have expired on about 47 percent, or 596 miles, of streets, rendering those limits unenforceable in most cases, according to LAPD and Los Angeles Department of Transportation officials.

“If a city like Los Angeles has unenforceable speed limits, that’s a recipe for disaster,” said LAPD Officer Troy Williams of the Valley Traffic Division.

So city officials have been working over the past two years to update the limits by doing “speed surveys” or studies, clocking how fast most people are currently driving on those roads. The focus has been on getting the limits updated and enforceable along major streets with the highest frequency of traffic injuries and deaths.

The speed surveys are required due to a state law aimed at preventing “speed traps” from being set with artificially low limits.

But that law has made it more difficult for Los Angeles officials to enforce its speed limits, especially with city staff shrinkages. Such reductions previously left two people to do the studies when there used to be seven.

Under state law, to be able to enforce speed limits, surveys must be done to establish, or re-establish the limits every seven or 10 years.

In 2015, the city was only able to enforce speed limits on 19 percent the streets that have them posted because of expired surveys.

Law enforcement officials say the backlog on surveys in recent years has hampered efforts to deter speeding on many city streets.

Williams pointed to a pair of recent, speeding-related collisions on streets in the San Fernando Valley “where we have had no enforcement for several years now.”

On Vanowen Street and Sepulveda Boulevard in Van Nuys, a car speeding down the road recently crashed into another vehicle stopped at a red light, resulting in an injury, he said. In another accident, a car speeding westbound on Vanowen Street near Platt Avenue crashed into a motorist who was attempting to make a left turn, resulting in a fatality, Williams said.

While LAPD officers can still “pace” vehicles, that method is not commonly used because it can be less safe and is impractical, according to Williams.

Pacing involves following cars to track driving speeds on streets with expired surveys. But Williams said having officers regularly tailing cars at dangerously high speeds for enforcement purposes can increase the risk of accidents happening.

“If a city like Los Angeles has unenforceable speed limits, that’s a recipe for disaster. — LAPD Officer Troy Williams, Valley Traffic Division

Los Angeles transportation officials say they have been chipping away at restoring enforcement on city streets, and with the help of more staffing and an outside engineering firm, have now completed many of the required surveys.

Speed limits stayed the same on hundreds of miles of streets as a result of the surveys. But they have also led to proposed speed limit increases or decreases on dozens of streets throughout the city. Those changes require approval by the Los Angeles City Council to go into effect.

If the proposed changes are approved, the number of miles with up-to-date speed limits would go up to 64 percent citywide. At the same time, speed limits on 100 percent of the street miles designated as part of a “high-injury-network” would be made current and enforceable, according to Transportation Department spokeswoman Lilly O’Brien.

Speed limit increases are being proposed for a total of about 94 miles on 26 street segments, the majority of them in the San Fernando Valley. Many of the limits are now set at 35 mph and would be raised to 40 mph.

Under the proposed changes, another 45 street segments, totaling about 52 miles, would see speed limits go down, while limits would be established on nine street segments totaling about 10 miles.

Williams said neighborhood councils have been contacted about the proposed changes, and he will be giving presentations on speed limit changes in the community over the next few weeks.

The proposed changes are set to be considered by the Los Angeles City Council’s Transportation Committee on Oct. 25. If approved there, they would go to the full council for a vote.