DTT Speed and Stopping Distances

Question 1

What is the default speed limit on a national road in Ireland when no other limit is posted?

Accepted Answer

100 km/h

Answer

The default speed limit on national roads (N roads) in Ireland is 100 km/h when no other limit is displayed.

Question 2

What is the default speed limit for cars in a built-up area in Ireland?

Accepted Answer

50 km/h

Answer

The default speed limit in a built-up area (urban area) in Ireland is 50 km/h unless road signs indicate otherwise.

Question 3

What is the national motorway speed limit for cars in Ireland?

Accepted Answer

120 km/h

Answer

The speed limit on motorways in Ireland is 120 km/h for cars and motorcycles.

Question 4

What is the total stopping distance made up of?

Accepted Answer

Reaction distance and braking distance

Answer

Total stopping distance is the sum of reaction distance (the distance travelled while the driver reacts) and braking distance (distance to stop once brakes are applied).

Question 5

How does doubling your speed affect your braking distance?

Accepted Answer

It quadruples

Answer

Braking distance increases with the square of speed, so doubling your speed quadruples your braking distance.

Irish DTT Practice Test

Irish DTT Practice Test

DTT Speed and Stopping Distances