HOLLYWOOD — A little after nine on a summer night, a pack of some thirty electric bikes came up the boulevard against traffic with their front wheels in the air, and the sidewalk tables paused mid-sentence to watch them pass.

For the teenagers on the bikes, the nightly ride is part sport and part scene — a rolling contest of who can pull the longest wheelie, hold the fastest line through traffic, and outrun anyone inclined to give chase. For a lot of the people they ride past, it is the summer’s leading nuisance. Both descriptions are accurate, which is much of the problem.

Many of the machines are ordinary consumer e-bikes. A growing number have been modified to shed their speed limiters and can hold close to 30 miles an hour, fast enough to keep pace with cars and to do real damage when they don’t.

“I have almost been hit twice on my own corner, once carrying groceries,” said Paula Nomura, 61, who has lived in the neighborhood three decades. “They ride on the sidewalk, they ride the wrong way, they run the light in a pack so you cannot cross. I don’t think they are bad kids. I think somebody is going to get killed.”

Complaints have stacked up at community meetings and in the inbox of Councilmember Alicia Rendón’s office, which says it is looking at where the fastest bikes are sold and how the city might reach the parents who buy them. The response is complicated by the machines themselves. Under state law some classes of e-bike require no license, no registration, and no minimum age past sixteen, and the fastest ones are often illegally altered in ways an officer cannot spot at a glance.

“We are not going to chase a sixteen-year-old on a bike through traffic and turn a nuisance into a funeral,” said Marcus Sheridan, a Los Angeles Police Department senior lead officer for the area. “The honest answer is that the tool we would normally use, a traffic stop, creates more risk than it solves. So we lean on the parents, and on the shops selling the kits.”

The riders tell the story differently. For teenagers priced out of cars and too young to drive them, a used e-bike is a first taste of getting somewhere under your own power, and the group ride is where the week happens.

“It is the cheapest freedom there is, and it is the only thing all my friends do together,” said Terrell Ruiz, 16, straddling a bike he said he bought secondhand with birthday money. “Some guys do dumb stuff, and then everybody blames all of us. There is nowhere we are actually allowed to just be, so we take the street.”

By eleven the boulevard had mostly emptied, the packs dispersed to driveways and garages across the neighborhood, the whine of the motors giving way to ordinary late traffic. The argument they leave behind reconvenes at the next community meeting, where everyone agrees something has to change and no one agrees on what.