During the first year of the project, we integrate an impact-echo device with a mobile robot for automatic NDT inspection of bridge decks to generate a 2D/3D map showing flaws. We found from field test that most of the bridge decks have groove surfaces to enhance the friction of the vehicles on the bridge. The current Impactecho device we used doesn’t work well in groove surfaces even if it is used in manual operation. After consulting with world renowned scientists and NDT firms, we got to know that the ultrasonic flaw detector with spring loaded sensor may provide a solution to this challenge.