You may be stoked that the numbers on your odometer go up to 140. But you should only hit your car's max speed when driving on the Autobahn or when being chased by a Decepticon. 

The rest of the time, you'll have to obey traffic laws and stay under the posted speed limit.

Don't automatically assume that you may drive 45mph just because you see a sign that tells you that's the limit. There's a "Basic Speed Law" in Alabama that states all drivers must maintain a speed that's safe given the conditions. In other words, if there's bad weather or fog, nearby pedestrians or cyclists, poor road conditions, or a large number of slow-moving Civil War reenactors in front of you, you'll have to reduce speed accordingly.

This is just one of those situations where you're going to have to think for yourself and exercise some decision-making skills.