Lauren Ressler often drives up and down Ventura Boulevard in Studio City, looking for an open parking meter -- a back-and-forth search that takes time and tests her patience.

"It's like a never-ending nightmare trying to find a spot," said Ressler. "I go up and down the block for twenty minutes looking for a spot."

The NBC4 I-Team uncovered one of the reasons why: valets are parking customers' cars at meters and sometimes even placing cones in the street to prevent drivers from getting parking spots. That's illegal, according to the Los Angeles Police Department.

"It's a major problem throughout the city," LAPD Detective Corey Harmon told NBC4. "It is not legal for (valets) to park at meters."

A City of Los Angeles Ordinance prohibits valets from parking customers' cars in the "public right of way," which includes parking meters and on side streets. The ordinance says valet companies must prove to the city that they have space in parking lots for their customers' cars.

But in various parts of the city, the I-Team found valets monopolizing meters, charging customers $5 or more to park their cars at $1 meters. It's a practice Mayor Eric Garcetti vowed seven years ago to stop when he was president of the Los Angeles City Council.

"Valets do not have a right to public parking spaces," Garcetti said in 2009, after another NBC4 investigation caught valets taking street parking away from the public.

But on streets like Ventura Boulevard in Studio City, the I-Team documented how valets were using most of the meters on some blocks to park cars, like the valets from the popular Katsu-Ya restaurant. When the valets used up all the open meters, they parked cars in loading zones, in front of driveways, even on the sidewalk -- all against the law, according to police.

Down the street, at the restaurant Barrel and Ashes, their valet company -- Bestway Valet Services -- told the city it's parking cars in a five-car lot behind the restaurant, according to the LAPD. But on numerous days and nights, the I-Team saw Barrel and Ashes valets parking cars in meters all along Ventura Boulevard and even in red zones.

When the I-Team told the manager of Barrel and Ashes that valets from the company his restaurant is using were illegally parking cars, Matt Carter said, "It's good news to know. That's definitely something I'll be talking to them about."

But the I-Team saw those valets continue to do it for weeks after.

"No more hogging of spaces. They will be prohibited from parking in public spaces on the street," Garcetti told NBC4 in 2013, after he sponsored a new City of Los Angeles law, requiring both individual valets and the valet companies to get city permits to operate.

That law went into effect in 2014.

"If you break the law, we're going to shut you down," Garcetti added.

But valet companies are still breaking the law and some are operating without the required permit, according to the LAPD.

On Fairfax Avenue, home to trendy shops and restaurants, numerous valet companies park cars all along the busy avenue, including Prime Time Parking Services. The I-Team noticed valets for Prime Time putting cones in the street to prevent drivers from parking at meters, so they can then charge customers $6 to park at a $1 meter.

The police say that's illegal, since LA's valet ordinance says, "cones shall not be placed on the road or on parking meters" by valets.

It's the job of the L.A. Police Commission to regulate valet companies and make sure they're following the law, but Detective Corey Harmon said, "We are outnumbered."

Harmon said the Police Commission only has a six-person team to watch over the hundreds of valets in Los Angeles, and that team also has to regulate towing companies and parking lots.

"With our limited resources, we're doing as much as we can. We can always do better," Harmon told NBC4.

Harmon said his team can only respond to complaints from the public.

When NBC4 questioned Harmon about the companies we saw breaking the law -- Bestway Valet, Prime Time Valet, and Katsu-ya -- he researched them and said none of them had permits to operate at those locations. It's unclear if the individual valets had their required permits.

The I-Team contacted those companies, and Mayor Garcetti, to talk for this story. None of them returned the I-Team's calls and emails.

The LAPD said if you know of a valet company that might be violating the law, call their valet hotline at 323-929-2568.