Fast. Easy. Discreet. RoadGuard Interlock gets you back on the road with a car breathalyzer that is FAST to warm up, EASY to use, and DISCREET so you can focus on the road ahead. As an approved Texas Ignition Interlock provider, we have convenient ignition interlock installation near you in Joshua, Texas at 318 N Broadway St. With a proven track record, RoadGuard Interlock offers top-tier ignition interlock devices that won't damage your vehicle, professional installation, and reliable customer service. Call us today to schedule an appointment for your car breathalyzer installation, calibration, or removal in Joshua or any of our other convenient locations throughout the state of Texas.