In Washington State, if you are required to have an ignition interlock device (IID) installed on all vehicles you drive there is an IID exemption for work vehicles.
There are several scenarios in which this may be helpful:
(1) Court requires an IID as a pre-trial condition of release pending trial; (court somtimes will send notice to DOL of IID requirement - can also ask court to exclude in courts written IID or conditions of release order)
(2) Ignition Interlock License (IIL) required during a DOL administrative or DUI/Physical Control conviction "hard" suspension period;
(3) IID required after the license suspension period because of a DUI/Physical Control conviction or 2nd et.al Reckless or Negligent Driving conviction within 7 years (i.e. 1, 5, 10 year restriction periods):
(4) IID required during a Deferred Prosecution.
To qualify for the IID exemption your employer requires you to drive:
(a) a vehicle;
(b) during working hours and;
(c) the vehicle is owned, leased, rented, or the temporary responsibility of your employer.
See link for DOL form and follow the instructions. IID Employer Declaration. You must carry a copy of this form on your person.