The fear of thieves stealing cars by pulling motorists from their vehicles means many drivers now insist on keeping their doors locked, according to a survey.
Insurance company Admiral found 60% of motorists keep the doors locked when driving through built-up areas at least some of the time.
And despite a fall in car crime, four out of five of the 2,667 adults polled said they worried about their car being stolen or broken into.
Those worrying the most are drivers in Northern Ireland and Yorkshire, with 88% fearing car crime. This contrasts with south-west England where 71% are worried.
Carjacking concerns are most prominent in London, where 69% of drivers say they lock their doors while driving some of the time.
The survey showed 19% of motorists reported having had their car stolen at some time and 44% have suffered break-ins.
London is the car crime capital, with 15% of vehicle owners in the capital having had their car stolen or broken into in the last year.
Admiral managing director Sue Longthorn said: "The reality of car crime suggests the people we surveyed are being over cautious. Carjacking is an extremely rare crime. In the last year we have only had five cases reported to us."
© The Press Association 2008