a system for measuring the wheel base of an automobile frame and the transverse and longitudinal offsets of its steered wheels which comprises a first device and a second device to be applied by known means to two automobile frame wheels positioned on the same side , said first device comprising two light emitting diodes located a known distance apart , measured in the horizontal plane , and said second device comprising optical angle measurement means arranged to measure the angle subtended between the light rays emitted by said light emitting diodes .