The static meet had been raising money for charity.
Two cars have collided and ploughed into a crowd at a car meet in Stevenage, injuring 17.
The incident took place late on Thursday evening and as seen in footage shared online, one car pulled out onto a main road and was hit by another speeding vehicle, sending the pair into a crowd of onlookers.
Following numerous online rumours regarding the number of casualties and their conditions, police confirmed that 17 people had been injured, some of them seriously.
The meet had been organised by the Cruise-Herts car club and was raising money for charity, but organiser Rix Sidhu insisted that street racing and irresponsible driving weren't condoned by those who put the event together.
"We don’t condone street racing, we organise static meet-ups," Sidhu said in a comment on Instagram. “But we can’t control everyone and we don't promote this. We are not boy racers, we are car enthusiasts."
"We held the meet in a car park with a speed bump at the entrance. But unfortunately some people went a bit rogue," he told the BBC. "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."
At the time of writing no arrests have been made, but Hertfordshire Police are investigating the incident.
"We weren't aware of this event taking place and we weren't aware of such large numbers attending the Stevenage area," chief inspector Alicia Shaw told the BBC, adding that the force had attended similar events in the past and had seized cars from dangerous drivers.