Hazard Perception Theory Flashcards

The stopping distance at 70 mph in dry conditions is approximately:

Answer: 75 m (245 ft)

At 70 mph the total stopping distance is approximately 96 m (315 ft), comprising 21 m thinking distance and 75 m braking distance — the length of more than six car lengths.

Which situation at a junction requires an ADI to teach the concept of 'effective observation'?

Answer: Emerging onto a major road with restricted sight lines — look, assess, look again and move only when safe

Effective observation at restricted junctions involves looking right, left and right again (and for one-way roads, left-right-left), reassessing continuously before committing to the manoeuvre.

What makes the crest of a hill particularly hazardous from a hazard perception standpoint?

Answer: Oncoming vehicles and pedestrians are hidden beyond the crest, requiring reduced speed to a safe stopping distance

A hill crest cuts off the driver's view of the road ahead; hazards on the other side may not be visible until very close, requiring speed to be reduced so the driver can stop within the distance they can see to be clear.

In hazard perception theory, a 'latent hazard' differs from a developing hazard in that:

Answer: It is a situation that has potential to develop into a hazard but has not yet done so

A latent (or potential) hazard is a situation that could develop — such as a ball bouncing near the road or a parked van obscuring a junction — requiring monitoring but not yet demanding action.

How does tiredness affect hazard perception and what should a driver do?

Answer: Tiredness slows cognitive processing and reduces the ability to detect and respond to hazards; the only cure is sleep

Fatigue impairs attention, slows reaction time and reduces hazard detection ability; opening a window or turning on the radio provides only minutes of relief; the only real remedy is stopping and sleeping.

When following a vehicle at night, why is it important not to over-drive your headlights?

Answer: The driver must be able to stop within the distance illuminated by their headlights

Driving faster than can be stopped within the lit area means the driver cannot stop in time for hazards at the edge of their light reach — a form of excessive speed for the conditions.