The state of Virginia (as you doubt already know, but others might
not) actually has special highway patrol vehicles, which aren't cop
cars, but rather cars that patrol the Interstates looking for broken
down vehicles. They have gas, and a few other things with the idea of
quickly moving vehicles again, that might hinder traffic flow. They
can also call up a tow truck if your vehicle is truly broken down and
not just out of fuel.