Traffic Control Measures (WJEC GCSE Science (Double Award)): Revision Note

Traffic Control Measures

• There are two ways to make travelling in a car safer:

  • Having cars move at a slower speed, so the stopping distance is shorter

  • Making traffic collisions safer if they do happen

Reducing Traffic Speed

• There are many methods employed on UK roads to reduce the speed cars can travel:

  • Speed limits

  • Speed humps

  • Speed cameras

Speed limits 

• Speed limits tell drivers the maximum speed they are legally allowed to drive on a section of a street

• In most urban (town) areas across the UK, the speed limit is 30 mph (miles per hour)

• In residential areas across the UK, the speed limit is sometimes reduced to 20 mph

  • This is because there is a higher risk of hazards on the road

    • Children playing

    • People walking

    • Other cars parking or manoeuvring

    • People opening car doors

    • Pets crossing the road

    • People taking longer to cross the road

• In Wales, most 30 mph roads have been changed to 20 mph roads

• This decision was made to:

  • Reduce the number of collisions and resulting injuries

  • Encourage more people to walk, cycle or use public transport 

  • Improve the health of Welsh citizens

  • Make the streets safer

  • Reduce air pollution

• A speed limit is indicated by the number of miles per hour inside a red circle on a post next to the road

An Example Speed Limit Sign

A 30 mph speed limit sign

• Speed humps are used to force drivers to slow down

• They are often used:

  • On roads prone to accidents

  • Outside schools and hospitals

  • In residential areas

•  Driving over speed humps can cause damage to cars and be uncomfortable for passengers

An Example of a Speed Hump

A speed hump in the road is designed to slow cars down

• Speed cameras 

  • Can be both mobile or permanent

• Mobile cameras are set up by the Police along any stretch of road

  • They record the instantaneous speed of cars using a laser gun

  • They are set up in areas notorious for speeding and dangerous driving

An Example of a Mobile Speed Camera

Police officers set up mobile speed cameras to temporarily check the speed of passing motorists

• Permanent speed cameras are erected on posts and record the speed of cars 24 hours a day

  • They measure the average speed of cars over a set distance

  • Are marked by white lines on the road

•  Permanent speed cameras are constructed along stretches of road where there may have been accidents or where mobile speed cameras have caught many offenders 

An Example of a Permanent Speed Camera

A permanent speed camera is constructed on a pole on the side of the road and is always recording the speed of passing cars

• If speed cameras catch motorists travelling above the speed limit then they can receive one or a combination of the following:

  • A fine

  • A warning

  • Further training via an online training course

  • Points on their driver's license

Safety Features in Cars

• There are many strict requirements in place for the safety features installed in modern cars

• These include:

  • Crumple zones

  • Airbags

  • Seat belts

• Car manufacturers are held accountable for how well these features perform 

  • New and old models of cars undergo regular testing to ensure they are up to standard

• Police officers are responsible for enforcing the law that all passengers travelling in a car are wearing a seatbelt

  • A seatbelt restricts the distance a passenger will move during an impact

  • It can stop a passenger from falling through the front windscreen for example