More than 40 motorists had their vehicles fitted with anti-theft screws during a police initiative in Bradford.
Neighbourhood policing officers visited Asda on Rooley Lane, where they also gave some people screws they could fix to their vehicles at home.
Sergeant Tany Ditta said: "We hope that by organising this campaign and alerting motorists, we can tackle this type of crime. I would like to thank Asda for providing their car park for this event. I would also like to thank the local community who were very supportive of the event and of the work carried out by the local safer neighbourhood team."