Traffic Control Measures (WJEC GCSE Physics)

• 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