The subject device and associated system relates generally to assessing impairment of an individual to determine whether to provide access to operate a motor vehicle, providing an ignition interlock that works without requiring modification in a motor vehicle and allowing an individual to start the vehicle only following measurement of blood alcohol content or following a series of cognitive tasks to determine the level of impairment. The systems and devices described herein relate incorporate a shielded case designed to disable communication between wireless car keys and the corresponding motor vehicles. This method of achieving an ignition interlock can be combined with a breathalyzer, or with a fingerprint alcohol sensor, or with cognitive tests running on a mobile computing device.
