What does it mean by tread width

[olason]

After reading this on my 1968 Olds 442, I was curious: http://www.ehow.com/facts_7467236_19...442-specs.html

It talks about the over all width of the car being 76.2 inches and then the tread width being 59 inches in the front and the rear. How is tread width measured? Because figuring it out to be per side the car width to the tread width comes to about 8.6 inches of overhang and I think that seems wrong. I am not at my car to measure it, but it just seems wrong when thinking about it.

Thanks in advance.

[astroracer]

The term is "track width". The center to center distance, cross-car, between the two front tires and two rear tires.
Mark