Breath out, start up.

CrimLaw links to an article discussing the New Mexico legislature's attempt to require all cars to have a device that requires the driver to blow into a breatalyzer before the ignition would start.

My hunch is this law would be invalid under the Dormant Commerce Clause as a undue burden on interstate commerce. I also think it would be invalid under a theory of field preemption due to the extensive involvement of the federal government.