While DUI laws are in existence across the country, it is important to know that the laws may change slightly depending on the state. Like many states in the union, Montana possesses an ignition interlock device law in certain circumstances. 
 
The courts may require you to install an ignition interlock device in your vehicle if you have a DUI conviction in the state of Montana. According to the state of Montana, the courts will require an individual convicted of DUI to install an interlock device if the courts have convicted him or her more than once for DUI or at the discretion of the Court. 
 
What is an ignition interlock device? 


An ignition interlock device is a little breathalyzer that a third-party company installs in your car. If you wish to start the car, you will need to breathe into this device to prove that you have not consumed alcohol prior to turning the vehicle on. Once the vehicle is in operation, you will need to breathe into the device occasionally to prove that you have not consumed alcohol while the car is in motion. 
 
Who needs an ignition interlock device? 
 
Persons convicted of multiple DUI offenses will need to install an ignition interlock device in their car in order to retain their driving privileges. In Montana, it is more rare for first time DUI offenders to need to install an ignition interlock device in their car, but this depends on the severity of the offense. 
 
If you need to install an ignition interlock device in your vehicle, the cost will be on you. Ignition interlock devices can potentially cost over $1,000 a year to maintain.