Devices which breath-test drivers before their cars start are being offered in County Durham in a bid to crack down on drink-driving.
The Durham force is the first in the UK to pilot "alcohol interlocks" which immobilise a vehicle if the driver is over the legal alcohol limit.
They will be offered to repeat offenders on a voluntary basis.
A suspected 285 road accidents have been linked to alcohol in County Durham in the last three years.
The initiative is part of Durham Police's checkpoint programme. In some instances where drinking is a factor, offenders will be asked to agree to have an alcohol interlock fitted to their car as part of a "behaviour contract".
The cost of the trial will be absorbed by the manufacturer, Smart Start.
Det Insp Andy Crowe, of Durham Police, said: "A number of offenders in our area have a problematic relationship with alcohol and we hope, as part of a wider programme, this will help them address their issues".
The devices are already commonplace in countries such as the US and Denmark.