I am followed just about every day of the week by a school bus that is on my bumper through the entire length of the school zone on Springbrook Road, behind North Medford High School. Do buses have to follow the posted speed limit? Does the speed start at the "school zone speed 20" sign and continue until you pass the next speed sign (not when you can read it)? And isn't that also the case on the highway when leaving a construction zone?

I am followed just about every day of the week by a school bus that is on my bumper through the entire length of the school zone on Springbrook Road, behind North Medford High School. Do buses have to follow the posted speed limit? Does the speed start at the "school zone speed 20" sign and continue until you pass the next speed sign (not when you can read it)? And isn't that also the case on the highway when leaving a construction zone?

— Michelle M.

Well, Michelle, not only is that school bus driver breaking the law by tailgating you, he or she is making it very difficult for you to respond with the appropriate hand signal, given that there are impressionable young children in the bus. Not that we here at the Since You Asked School of Driving and Manners are encouraging any unseemly gestures, but just saying ... .

For a more official answer, and probably a more polite one, we turn to the guy with the answers to driving laws, Sgt. Dace Cochran of the Jackson County Sheriff's Department.

The good sergeant says your first question is easy: All vehicles, including school buses, have to obey the 20 mph designation in school zones when the school zone speed is in effect.

As to when the speed zone starts, that happens as you pass the sign, so a driver should be traveling at 20 mph by the time he or she passes the sign. They then need to stay at 20 mph until they come to and pass either a sign designating "end of school zone" or the next posted speed limit sign.

A driver cannot legally drive at the next posted speed just because they can see the applicable sign in the distance, but have to wait until they pass that sign before speeding up. If that weren't the case, officers might have to give eye tests to drivers, to determine how far they can see, before issuing a ticket.

That rule applies for all speed zones, not just school zones. So that covers your last question regarding construction zones, where the reduced speed would continue until you reach the "end construction" sign or the next posted speed sign.

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