Arizona pinstriping

Arizona pinstriping (or Arizona pinstripes) is the colloquial term for the thin, shallow scratches along the sides of trucks and SUVs usually formed when branches, twigs, or thorns scrape along the side of the passing vehicle. This term likely originates from Arizona, a U.S. state well-known for its adventurous Wild West culture and numerous off-road trails. Generally, scratches that are severe enough to remove layers of paint are not considered Arizona pinstriping.

In off-roading culture, the term is often used to differentiate off-road-capable trucks and SUVs that are actually "used" off-road from their urban and suburban counterparts that are used almost exclusively on paved roads and are purchased mostly as status symbols. An off-road-capable vehicle (especially SUVs) with "Arizona pinstriping" is generally considered evidence that the owner actually uses the vehicle for its intended purpose.

References

http://www.doubletongued.org/index.php/dictionary/arizona_pinstriping/