A 12-year-old boy is in a serious condition in hospital after being knocked down by a car as he crossed the road wearing a pair of "wheelie shoes".
Heelys are trainers which have wheels in the heel
Jarred Twaits was hit by a car on Sunday as he crossed Vale Road, in Seaford, East Sussex.
His parents said the road was dangerous and questioned whether the wheeled shoes, called Heelys, had anything at all to do with the collision.
Officers were investigating the circumstances surrounding the accident.
Jarred is being treated at King's College Hospital, in London, where he has undergone emergency surgery to relieve pressure on his brain.
The Ibiza Seat car was being driven by an 18-year-old local man, who police said had not been charged.
Sussex Police confirmed the boy was wearing trainers with wheels, which are known as Heelys.
The shoes have a single or double wheel in the heel that allows the wearer to go from walking to rolling simply by shifting their weight to their heels.
Totally Phat, the UK's largest seller of official Heelys, acknowledged there could be some dangers associated with children wearing the shoes.
However, it said there were a number of "dangerous counterfeit models" on the market which had not been stringently tested.
"Totally Phat has a clear safety policy in place with a safety notice posted in all stores," it said.
"All staff are fully trained to wear Heelys and teach each child how to use them safely."
A statement added that it recommended parents insisted on their children wearing safety equipment while using the shoes.
The Royal Society for the Prevention of Accidents (RoSPA) has advised children not to wear them when crossing the road.
Spokesman Roger Vincent said: "Don't use them on, or near, roads, and in busy shopping centres where other people could get hurt."
Since Christmas, 11 children have been admitted to two hospitals in Northern Ireland with injuries suffered while using wheeled trainers.
Mr Vincent added that in-line skates and rollerskates resulted in about 20,000 accidents requiring hospital treatment each year.
"If you put another wheeled shoe on the market you can expect more, particularly as people learn how to use them.
"The enjoyment you get out of them should outweigh the possibility of accident. But some people will get hurt," he said.