Seventeen people have been injured in a “horrendous” crash at a gathering which included modified vehicles in Stevenage.
Two vehicles collided on Monkswood Way at about 21:45 BST on Thursday during the “car cruise” event and hit people watching from the side of the road.
The East of England Ambulance Service said some of the people had been seriously hurt.
Police have asked witnesses to send footage of the crash to detectives.
Video footage shows one car passing another before the two collide and one ploughs into spectators at the roadside.
One witness said on Twitter: “I’ve just witnessed that horrendous crash in Stevenage, no more than 50ft away from me. I’m still trying to process it all.”
Police, fire and ambulance services all attended the crash
Hertfordshire Police said it was investigating and no-one had been arrested.
An East of England Ambulance Service spokesman said: “There were a number of people in the area at the time and 17 people are presently being treated for injuries, some of which are serious.”
A group called Cruise-Herts had said it was holding a cruise event on Thursday where people would gather to look at modified cars.
Organiser Rix Sidhu said he had been organising similar meets for 17 years and the gathering on Thursday was to raise money for charity.
He estimated one of the cars that crashed was travelling at 60 or 70mph and then went into the crowd “at speed”.
Mr Sidhu said: “We held the meet in a car park with a speed bump at the entrance. But unfortunately some people went a bit rogue.
“We try and stop that, we urge people…not to go out on the roads, not to risk injury or anything.
“But unfortunately, in this age of social media and Snapchat, people want to get footage and post things to their friends, which seems to drive some people to the main road.”
Fellow organiser Dean Summerbee, 34, described the crash as a nightmare and said people attending had been warned not to race or do wheel spins and burnouts.
He said: “It was horrific seeing it last night. It still plays over in my head in slow motion. I literally had to pull my mate out of the way.
My thoughts go out to everyone who has been hurt. It’s not something I’d like to relive again.
“I was extremely close to the crash, less than 15ft away. I feel sorry for anyone who witnessed it. It was a nightmare last night.”
Ciaran O’Connor, 33, was travelling home when he witnessed the crash.
He said: “We saw the fast car coming towards them and there was just a scene of kids lying in the road, some of them motionless and people around them trying to help them. It was horrific.”
Hertfordshire Fire and Rescue Service said crews had cut free one person trapped in a vehicle and provided “trauma care” to a number of injured people.
The air ambulance was also sent to the scene.
At the scene
By Adam Jinkerson, BBC News
Last night there were hundreds of people here, but this morning the only sign anything happened is an abundance of skid marks in the adjacent car park – and police markings on the road at the scene of the crash.
There are yellow spray-painted markings that seem to indicate where the two cars involved were travelling, the point at which they met – and where they came to rest.
Some of those markings are on the pavement.
I can also see that first aid was given here.
There are are a few bits of medical paraphernalia left among the rubbish, which is now the only other evidence of how many people were gathered here last night.
www.bbc.com
