A wheel alignment adjustment system includes sensing apparatus for sensing alignment characteristics of a vehicle to be aligned, and a memory for storing alignment specifications for a plurality of vehicles and alignment adjustment parts. As a result, the airfuel ratio can be accurately controlled to one other than the stoichiometric airfuel ratio, even when an O2 sensor that produces an output whose property only changes near the stoichiometeic airfuel ratio is used. The first user interaction may include interaction with a first display displaying a plurality of applications on the first test device.