Traffic Control Measures

Section 1 of 6Two ways to improve road safety

Lower speeds

• Lower speeds Slower vehicles have shorter stopping distances, so drivers can stop before reaching a hazard.

Safer collisions

• Safer collisions Features such as seat belts, airbags and crumple zones reduce injury if a collision does happen.

Section 2 of 6Speed limits

What they are

• What they are A speed limit is the maximum legal speed on a road, shown by a number inside a red circle on a sign.

Typical values

• Typical values Most urban roads in the UK are 30 mph, and many residential streets are 20 mph.
  • In Wales most former 30 mph roads are now 20 mph.

Reasons for lower limits

• Reasons for lower limits There are more hazards in built-up areas,
  • such as children playing, pedestrians crossing, parked cars pulling out and opening doors.
• Lower limits also cut collisions, encourage walking and cycling, improve health and reduce air pollution.

Section 3 of 6Speed humps and cameras

Measure	How it works	Advantages	Disadvantages
Speed hump	A raised section of road forces drivers to slow down	Works all the time without enforcement; used outside schools and hospitals	Can damage vehicles, uncomfortable for passengers
Mobile speed camera	Police set up a laser device to measure the instantaneous speed of passing cars	Can be moved to places where speeding is a problem	Drivers only slow down where they see it
Permanent speed camera	Mounted on a post and records vehicles all day, often measuring average speed over a set distance	Constant monitoring; encourages steady speed	Expensive to install; drivers may brake suddenly when they see it

Section 4 of 6Why slower speeds save lives

1Lower speed

• Lower speed The vehicle has less kinetic energy.

2Shorter stopping distance

• Shorter stopping distance Both thinking and braking distances are reduced.

3Fewer collisions

• Fewer collisions The driver is more likely to stop in time.

4Less severe injuries

• Less severe injuries If a collision does occur, less energy is transferred, so injuries are less serious.

Section 5 of 6Key terms

Term	Meaning
Speed limit	The maximum speed at which vehicles are legally allowed to travel on a road.
Speed hump	A raised section of road designed to force drivers to slow down.
Speed camera	A device that records the speed of passing vehicles to enforce the limit.
Average speed camera	A system that measures how quickly a vehicle covers a set distance between two points.
Stopping distance	The distance travelled between seeing a hazard and coming to a halt.

Section 6 of 6Exam technique

1

Saying speed cameras physically slow carsthey record speeds and rely on the threat of a penalty.

2

Forgetting to link slower speed to a shorter stopping distance when explaining why limits help.

3

Thinking speed limits are advisorythey are legal maximums.

4

Giving only advantages when asked to evaluate: include a disadvantage as well.

5

Mixing up mobile cameras (instantaneous speed) with permanent cameras (often average speed).