Here's the "official" NSRA Vehicle Safety Inspection Requirements:
"....on both the front and rear suspension of the vehicle, stretch a taut string from the bottom of each wheel rim to the bottom of each of the other three tires AT THE ROAD SURFACE. If any part of the steering, suspension, or chassis is below this string, the vehicle will fail scrub line test....."
If you lose air in either front tire, anything below that line will contact the ground, and then you're basically driving a 3500 pound sled with no steering. Very dangerous.
