Collecting information on the condition of large and complex bridge decks by conventional means can be difficult and present safety concerns for inspectors and the public. Ground penetrating radar is a technology that solves this problem. Penetradar Corporation specializes in the inspection of large and complex bridge decks with our patented ground penetrating radar (GPR) four antenna array which allows simultaneous collection of radar data across a twelve foot lane in one pass. Four channels of radar data are collected with the same distance referencing eliminating inconsistencies in distance correlation between radar passes which are a problem associated with single and dual channel systems that must make multiple passes to cover a lane. With our system, we can scan large and complex bridge decks efficiently and economically in just a short time with a single pass over each lane collecting data at highway speeds, thereby eliminating traffic congestion, road closures and safety concerns.