Technically speaking, it is illegal to go even one mile per hour over the limit. So a police officer could, theoretically, pull you over for going 41 mph in a 40-mph zone—in reality, however, most officers won’t ticket you unless you’re going at least five miles per hour over the speed limit.
It’s important to keep in mind that each officer has some degree of discretion. Some officers might be super strict—and you’ll see flashing lights behind you even if you’re just a few miles per hour over—while other officers are more lenient, and won’t pull you over unless you’re driving significantly above the speed limit (i.e., 10+ mph).
Another thing to keep in mind is context. Going eight over in a school zone is very likely to get you a ticket, whereas going eight over on a five-lane highway is much less risky if you’re moving with the flow of traffic.
At the end of the day, it’s important to keep in mind that speed limits are posted for a reason. You’re breaking the law if you exceed the speed limit, so it’s probably best to take your foot off the gas—that way, you can get where you’re going without worrying about a ticket!
MORE: How long does a speeding ticket stay on your record?