Rental electric scooters are invading cities across America — but not everyone is embracing the trend.

Bird is a scooter rental start-up founded in California a year ago and has since expanded to various cities across America.

Finding a scooter is easy. In Southern California, they are left along the sidewalk, where anybody can rent them. An app on your phone will help you locate the nearest ride.

The scooters, however, are not without controversy.

In some cases, riders are zipping down sidewalks instead of the street, which is illegal. In others, kids under 18 are taking the scooters for a spin, which is against Bird's rules. And many are riding without a helmet, which is prohibited as well.

Some local California residents are furious. David Bourne, who owns a shop that rents bikes, is frustrated by the deluge of scooters.

"They are pretty much out of control," Bourne told Inside Edition. "It's taking money from us, which is unfair."

And one lawyer says her office is being inundated with calls about Bird-related accidents. Los Angeles personal injury attorney Catherine Lerer represents a woman who was taking a scooter for a test drive when she was injured.

"I'm getting calls from riders who are injured when there's malfunctions with the scooters," she said. "I'm getting calls from pedestrians who are tripping on scooters that are left abandoned on sidewalks. I'm getting calls from pedestrians where riders are crashing into them."

There's money in these scooters, however. Bird, which launched last September, is now valued at nearly $2 billion. A rival of Bird's, Lime, is valued at $1 billion.

“While we do not comment on specific incidents, safety is a top priority for Bird. We have taken several steps to communicate to our riders how to safely and lawfully ride a Bird. This includes: requiring riders to upload a valid driver’s license and confirm they are older than 18, providing an in-app tutorial, posting clear safety instructions on each Bird, and providing free helmets to all riders who request one. At last count, Bird has distributed more than 30,000 free helmets,” a Bird Spokesperson told InsideEdition.com.

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