You are stuck behind a slow vehicle on a two-lane road and a passing zone opens. May you exceed the posted limit briefly to complete the pass?

Why A is correct

Speed limits are ceilings, not baseline speeds with a passing allowance on top. A pass must be planned within the legal limit: you need enough clear sight distance ahead that the manoeuvre completes without ever needing more than the posted number, or you do not start it. The temptation to exceed the limit for a few seconds is exactly the scenario that produces head-on collisions, because the pass that required law-breaking speed is by definition a pass started without enough margin, in the teeth of traffic you may not yet be able to see.

Why the other options are wrong

B. No; passing is prohibited on all two-lane roads

Passing is exactly what two-lane roads are engineered for, in marked zones with adequate sight distance. Rejecting all passing confuses the legal manoeuvre with the illegal shortcut of doing it above the limit.

C. Yes, provided the pass is completed within a reasonable time

A 'reasonable time' standard is not in the law. The limit binds throughout the manoeuvre, and the driver who plans passes that fit inside it never has to test how a court reads 'briefly'.

D. Yes, if you flash your headlights at the vehicle being passed

Headlight flashing is a courtesy signal about your presence, not a licence to exceed the limit. Whatever you communicate to the slow vehicle, the oncoming traffic you may meet has received no message at all.

On the road

A combine, a broken yellow line stretching to a crest, and a long clear view: you hold your speed at the limit through the entire pass, which turns out to be enough from start to finish. If the geometry had demanded more than the limit, that would have been the sign the pass was never on — the zone is legal because the limit fits it, not because it excuses you from it.

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