A 3-minute lesson from the South Dakota course. Read the rules and examples, follow the handbook page references, and check your understanding before you move on.
Big vehicles need extra room to turn and merge, and buses bring hazards of their own: frequent stops, people running for them, and tail swing.
Know the rule
A truck or bus turning right may swing wide to the left first to clear the curb. Don't squeeze between it and the curb; wait until it has completed its turn.
Merge at the speed of traffic, and never merge in front of a truck or bus and then slow down. Keeping a steady speed lets trucks entering the freeway merge without stopping.
Never park on a runaway truck ramp or its entrance; it's illegal. Smoke coming from a truck's or bus's brakes may signal a runaway: get out of the way and don't get in front of it.
If you see an inter-city bus ahead, move to another lane before it stops. Pass a parked bus with care: it may pull out, and people may run in front of it or run to catch it.
A semi signals right at a corner and swings wide to the left. Stay behind it. Don't pull into the gap by the curb, or you'll be squeezed as it completes the turn.
Check your understanding
Read the question, decide on an answer, then open it to check the explanation. These are Roadwise study questions based on the source handbook.
When a truck or bus makes a right turn, why might it first swing wide to the left?
To clear the curb or an obstruction
To signal its intention more clearly
To check its mirrors for bicycles
To let faster traffic pass on the right first
Answer: To clear the curb or an obstruction
Trucks and buses sometimes swing wide left before a right turn to safely clear the curb or another obstruction.
