LOS ANGELES — Ginny-Marie Case can't forget the night she was jarred from her sleep by massive explosions set off by crews filming last summer's blockbuster movie "Transformers."

It was the latest cinematic nightmare that led Case and other residents streaming downtown as part of a population boom to push for tougher limits on filming in the nation's most popular location for movies, TV shows and car commercials.

"It was the loudest explosion I ever heard," Case said. "We had no clue: Was this part of filming? Was this some terrorist thing?"

For decades, filmmakers have depended on downtown's rail yards, brownstones and beaux arts facades to depict urban anywhere. In the process, they have grown used to operating with few restrictions in the long-neglected urban core.

"I do love movies, but sometimes it gets annoying. This is not a Hollywood lot," Oscar Linares, 32, said as he walked his Maltese past a set for "CSI: NY" where Gary Sinise stood before whirring cameras in a bulletproof vest.

The conflict pits the downtown resurgence against the push to stop the "runaway production" that occurs when filmmakers leave Los Angeles to take advantage of hefty tax breaks and other advantages offered by cities from Vancouver, British Columbia, to New Orleans.

Jack Kyser, chief economist at the Los Angeles County Economic Development Corp., said tighter downtown restrictions could send production companies packing.

"Hopefully they can come up with something the makes everybody happy, but that could be very difficult," Kyser said. "We really run a risk."

LURE OF BIG PROFITS

The entertainment industry generates $58 billion a year for the Los Angeles-area economy — a figure that has steadily increased in recent years as losses from runaway production leveled off and cable TV production increased, Kyser said.

Hollywood, however, is currently reeling from the estimated $2.5 billion toll taken by the recent writers strike.

City Councilwoman Jan Perry, whose district includes most of downtown, is watching closely as neighborhood activists and studio representatives work to draft the guidelines limiting overnight filming and curtailing street closures.

"People live here now, so at some point you've got to shut off the lights and let people go to sleep," Perry said. The City Council will have the final say on the rules.

Downtown has seen a lot of action over the years.

In "Transformers," giant robots wrestle on the streets, leaving a path of destruction created with a mix of actual footage and computer effects.

Action flicks such as "Die Hard 2" used City Hall as a backdrop, while the Art Deco Union Station was featured in the classic science-fiction thriller "Blade Runner."

These days, downtown plays itself on the Fox action series "24" and stands in for New York and Las Vegas in two of the three hit "CSI" shows on CBS.

It's also a hot spot for car commercials featuring the glass-and-steel office towers of Figueroa Boulevard.

23 SHOOTS A DAY

In all, there are an average of 23 downtown location shoots each day, according to FilmL.A. Inc., the nonprofit agency that handles filming permits for the city.

"We couldn't do our show without downtown Los Angeles," said Peter Lenkov, executive producer of "CSI: NY." "There's a grittiness to downtown you can't find anywhere else in Los Angeles ... Nowhere else do you get the feeling of 47th Street or Times Square."

Until the late 1990s, film crews could operate with nearly complete freedom downtown, which became a virtual ghost town overnight after government and office workers fled for the suburbs.

But the number of residents in the area has been increasing drastically, growing from about 18,700 before 1999 to more than 34,000 today, according to the Central City Association.

Shopkeepers and residents tolerated the street closures, floodlights and other inconveniences until late 2006, when a cluster of disturbances — including the "Transformers" explosions — pushed many over the edge.

Bert Green decided he'd had enough when film crews monopolized parking spots for months near the galleries where he organizes a downtown art walk.

After his complaints were ignored by city officials and FilmL.A. staff, he met with other merchants and residents who were fed up with filming.

"Crews were coming into the neighborhood and shutting streets down, or taking over whole blocks," he said. "There has to be some accountability."

Some limits exist already, but residents complain they are routinely ignored because they are not formal city ordinances.

One proposal under consideration by residents and studios would bar filming near homes from 11 p.m. to 6 a.m. without written permission from residents. It also cuts the amount of curb space crews can occupy and put limits on their use of lights, among other regulations.

Meanwhile, to ease conflicts, FilmL.A. has hired a community liaison to field complaints and asked police to make sure officers who guard filming locations enforce permit requirements.

"CSI: NY" location manager Timothy Hillman said he hits the street long before the cameras arrive to warn residents about the coming commotion and to reimburse shopkeepers who lose business.

"The locations are like my field," Hillman said. "If I burn out a location — if a location says 'I don't want you back' — it's like I'm a farmer throwing salt on his fields."