What instrument is typically used to measure wheel alignment angles?

The instrument typically used to measure wheel alignment angles is an alignment machine or a caster/camber gauge. These tools are specifically designed to assess the angles of the wheels in relation to the vehicle's body and to each other.

An alignment machine usually consists of a set of sensors or cameras that capture the position of the wheels and analyze their angles—such as camber, caster, and toe—in a highly accurate manner. Proper wheel alignment is crucial for ensuring optimal vehicle handling, tire wear, and overall driving safety.

A caster/camber gauge is a simpler, more manual tool that can still effectively measure these angles. It typically includes a protractor-style device that can be attached to the wheel to provide readings of the camber angle directly.

The other instruments mentioned do not serve this purpose. A torque wrench is used for tightening bolts to specific settings, a pressure gauge measures fluid pressure in various systems, and a digital voltmeter is used for electrical measurements. Hence, they are not applicable for wheel alignment measurements.