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 Missouri Ignition Interlock provider, we have convenient ignition interlock installation near you in Springfield, Missouri at 2835 East Division 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 Springfield or any of our other convenient locations throughout the state of Missouri