DTT Speed and Stopping Distances 3

Question 1

What does reaction distance depend on?

Accepted Answer

The driver's speed and reaction time

Answer

Reaction distance is determined by how fast the vehicle is travelling and how long the driver takes to react to a hazard.

Question 2

A speed limit sign showing '30' in a red circle in Ireland means:

Accepted Answer

Mandatory — you must not exceed 30 km/h

Answer

A speed limit in a red circle is a mandatory restriction — it is illegal to exceed that limit on that road.

Question 3

Why should drivers reduce speed when approaching a junction?

Accepted Answer

To allow more stopping distance if a hazard emerges from the junction

Answer

Reducing speed near junctions increases the time and distance available to react if another vehicle or pedestrian appears unexpectedly.

Question 4

What is the effect of worn tyres on stopping distance?

Accepted Answer

Longer stopping distance due to reduced grip

Answer

Worn tyres have less tread depth, which reduces their ability to disperse water and grip the road, significantly increasing stopping distance.

Question 5

If a vehicle's speed increases from 50 km/h to 100 km/h, the braking distance:

Accepted Answer

Quadruples

Answer

Braking distance is proportional to the square of speed; doubling speed (50 to 100 km/h) means braking distance increases by a factor of four.

Irish DTT Practice Test