The drivers of two cars that crashed into crowds at a charity meet in Stevenage have been identified, police have said. Seventeen people were injured in the incident, some seriously.

The pair, who have not been named, were interviewed as part of Hertfordshire police’s investigation, assistant chief constable Nathan Briant said on Friday.

The East of England ambulance service said it had taken 12 people to three hospitals: Lister hospital in Stevenage, Watford hospital, and the Princess Alexandra in Harlow. An air ambulance also attended the incident.

Footage on social media showed a car passing another vehicle before the two collided and one ploughed into spectators. 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.”

Spectators claimed that at least one of the vehicles involved, a Nissan 350Z and a Toyota GT86, was travelling at up to 70mph when the crash occurred.

A group called Cruise-Herts had said on Facebook that it was holding a car meet on Thursday to raise money for a charity supporting bereaved parents.

Rix Sidu, a member of the group, said at the scene that the atmosphere after the crash was “horrendous”. He added: “Me, myself, as a club owner, I felt sick. This has obviously had a big impact on us.

“I think a lot of people were in shock and realistically now it has shown people just how dangerous it can be, racing here. To see an individual get cut out of his car was horrible. To see people on the floor not able to move, it wasn’t a nice sight.”

He said said the meet was being held in aid of the 4Louis charity, an organisation that supports those affected by miscarriage, stillbirth and the death of a baby or child. He said organisers were trained in first aid, and that a liaison officer worked with police to pass on the registration plates of anyone causing trouble.

He added: “Nobody wanted this. We try so hard to make sure this doesn’t happen. We beg people not to race on the roads. If they want to race, there are places they can go for that, tracks where they can go at speed.”

He said organisers had decided to cancel all further meets.

In an update on Friday afternoon, Briant said: “Hertfordshire constabulary is continuing to work with partners to fully understand the events of yesterday evening in Stevenage. To date we have identified the drivers of both cars involved in the collision, and they have been interviewed as part of the ongoing investigation.

“Hertfordshire constabulary has never received prior warning of events such as the one yesterday evening. However, we have previously responded to such gatherings where concerns have been raised by the public.

“Whilst the events do occur regularly, the meeting yesterday evening appeared far larger in nature than previous events, and it is now understood that an organiser had publicised the meeting on social media as a charity event.”

Briant added that police had identified 130 witnesses on Thursday night and formed an investigation team to collect their statements. He said a large number of people who left the area before police arrived were likely to be needed as witnesses to the collision.

People who were at the scene, particularly anyone with video or dashcam footage, are being urged to contact Hertfordshire police.