A minimum speed is posted on the interstate you have just joined, but a mechanical fault means your car cannot sustain it. What is the right response?

Why C is correct

Minimum limits exist because a large speed differential is itself a crash mechanism. Traffic arriving at highway speed onto a vehicle crawling far below it produces rear-end collisions about as reliably as outright speeding does. When a fault rather than a choice is keeping you slow, the answer is to remove yourself from the flow rather than to argue with the sign: hazard lights, the next exit, or a position completely off the roadway. Minimums bind everyone using the roadway, not merely commercial operators, and 'my car cannot manage' is a reason to leave it — not a defence for staying on it.

Why the other options are wrong

A. Keep to the right lane and press on regardless

Remaining in the lane does not neutralise the hazard your speed created. A vehicle far below the flow with its warning lights on is still something approaching drivers must react to.

B. Sound the horn so faster traffic knows to go around you

The horn communicates irritation rather than information. Even where the sound carries, it conveys nothing that whoever hears it could act on: there is no request contained in it, and no way to translate a blast of noise into what any driver behind should do next.

D. Nothing — minimum limits bind commercial vehicles only

Minimums are posted for the roadway and attach to everyone on it. Exempting private drivers would defeat the purpose the sign was installed to serve.

On the road

A car with a failing cooling system crawls along the interstate because pulling over feels like giving up. Behind it, a queue is arriving at highway speed. The gap between sixty and thirty is where that particular story ends. Nobody in the queue had any warning that the vehicle ahead was travelling slowly rather than momentarily slow, and nothing except hazard lights communicates that.

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