You plan to turn right from a city street into a driveway. How far in advance of the turn must you activate your turn signal?

Why A is correct

The law requires a continuous signal during the last hundred feet before a turn — roughly four car lengths — which is the distance other road users need to register your intention and react to it. The requirement is 'continuous' as well as distance-based: an indicator that flicks on and off, or one activated as the wheel already turns, communicates nothing to the cyclist at the driveway mouth or the driver decelerating behind you. Signalling is how a private plan becomes public information, and the hundred-foot standard is the minimum exchange rate for that translation.

Why the other options are wrong

B. Signals are advisory and may be omitted when the turn is obvious

'Obvious' turns are the ones that most need signalling, because the driver's confidence that a turn is obvious is exactly what the pedestrian, cyclist or follower cannot verify. The requirement makes no exception for turns the signal-er considers self-evident.

C. The moment the turn begins is sufficient, provided the indicator is on

Signalling as the turn begins defeats the entire purpose: the information arrives at the same moment as the manoeuvre, when everyone affected needed it seconds earlier to make their own decisions.

D. One full minute before the turn, whatever the traffic

A fixed clock time scales badly — a minute in freeway terms is a mile of signalled intention, a minute on a residential street barely reaches the corner. The law expresses the requirement in road distance precisely so it matches the decision distance of following traffic.

On the road

You are the third car back when a driver ahead swings into a coffee drive-through with no signal, wheel already turning. Everyone behind brakes in a chain. On your own turn twenty metres later, the indicator clicks on at the hundred-foot mark and a cyclist at the driveway eases off instead of braking — the same street, the same manoeuvre, the difference made by four seconds of light.

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