There is a quick and easy way to do this in your driveway if you want.

Park with the steering wheel straight and the car on a level surface.

Grab a 2x4 that is long enough to cover the track width of the vehicle.

Lay the 2x4 on the 2" side so that it is at it's tallest and place it in front of the car, just touching the front of the tires.

Find a common point of measurement on each tire, and measure the width.

Now lay the 2x4 behind the tires and take the same measurement.

Subtract the rear measurement from the front and that will tell you if you are positive or negative, and a little bit of geometry will give you the actual angle.

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