A round the clock operation was mounted by police to target thieves breaking into vans in Sheffield.
Officers patrolled the city checking that vans were locked and using an automatic number plate recognition camera looking for thieves known to the force.
They were involved in two police chases with vehicles which failed to stop and they made arrests for drink and drug driving.
Officers found a knife after stopping one car and issued a caution after finding cannabis in another.
Inspector Jason Booth said: "This week we have been running a proactive operation to address the issue of vans being broken into overnight.
"We have been working into the early hours with a car fitted with automatic number plate recognition as well as both marked and plain vehicles.
"We have stopped a number of vehicles and gained some valuable intelligence.
"We have been checking vans parked up overnight to ensure they are locked and secure.
"We have more proactive operations like this one planned and its a positive attempt to address what has been a local concern with vans being attacked overnight.
"We appreciate these thefts can impact upon business and people's jobs and we are keen to do anything we can to catch those responsible.
"We value the support of local residents in reporting suspicious behaviour."
Call South Yorkshire Police on 101.