In an effort to shift road alignment surveying from manual to automatic methods, moving objects—such as a vehicle on which a Global Positioning System–inertial measurement unit (GPS-IMU) is mounted—are being used to perform surveys and obtain more accurate results. Two road alignment survey methods are compared: an affordably priced microelectromechanical system (MEMS) GPS-IMU and a high-priced fiber-optic–type GPS-IMU. Cross-section angle values from a stationary laser scanner survey and a GPS-IMU survey are compared to determine whether the roll attitude value of GPS-IMU can be used to ensure a more accurate comparison of the cross-section angle. In addition, GPS-IMU performance is compared under various test conditions to survey road alignment, and results indicate that the fiber-optic GPS-IMU is needed to ensure accuracy within the 10% margin of error required for road alignment. In a test conducted to verify whether the roll value of a vehicle can be used as is to survey the cross-section angle of a road, the values from GPS-IMU, drawing, and laser were within a 1% margin of error. Thus, it would be possible to use the roll value obtained from a vehicle as is to survey the road cross-section angle accurately.