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What could be done to combat speeding on our roads?



There have been many reports of motorists using the lack of traffic on the roads during the Covid19 lockdown to flout the speed limits and now with more traffic back on the roads there is a danger that some may continue to drive at excessive speeds even after things are back to ‘normal’.


Behavioural Science in transportation (understanding the behaviour and motivations of transport users such as motorists and rail commuters etc) is a fascinating subject which plays a big part in the engineering and design of roads and their ‘furniture’ in an attempt to gently persuade drivers to modify their driving behaviour to something more appropriate. 


There are many such psychological tactics in place to combat speeding but could we be doing more? What other engineering solutions could be implemented to stop excessive speeding? How do different countries tackle speeding on their roads? What could we learn from them? 

Parents
  • Braking Distances



    Kinetic Energy.  Braking distance increases four times each time the starting speed doubles.  This is because the work done in bringing a car to rest means removing all of its kinetic energy.


    Work done = kinetic energy.



    Work done = braking force x distance.


    W = F x d.



    Kinetic Energy = 1\\2 X mass X velocity2.



    This means that:



    F x d = 1/2 x m x v2



    Therefore, for a fixed maximum braking force, the braking distance is proportional to the square of the velocity.



    Question.



    Calculate the total breaking distance of a car travelling at 12m/s, when the driver’s reaction time is 0.5s and they see a child run into the road?



    Additional Information:



    Car Mass: 900Kg.



    Braking Force: 2000N.



    Calculations:



    Part 1.  Reaction (Thinking) Distance:



    Distance = speed x time.



    d = v x t.



    Therefore, d = 12m/s x 0.5s



    Thinking Distance = 6m.



    Part 2.  Braking distance calculation:



    F x d = 1/2 x m x v2



    Transposed:



    d = (m x v2)/f x (1/2)



    d = (900 x 122)/2000 x (1/2)



    Braking Distance = 32 metres.



    Therefore, the total stopping distance is:



    Stopping distance = Reaction distance + Braking distance.



    Stopping distance = 6 + 32.



    Answer: 38m


Reply
  • Braking Distances



    Kinetic Energy.  Braking distance increases four times each time the starting speed doubles.  This is because the work done in bringing a car to rest means removing all of its kinetic energy.


    Work done = kinetic energy.



    Work done = braking force x distance.


    W = F x d.



    Kinetic Energy = 1\\2 X mass X velocity2.



    This means that:



    F x d = 1/2 x m x v2



    Therefore, for a fixed maximum braking force, the braking distance is proportional to the square of the velocity.



    Question.



    Calculate the total breaking distance of a car travelling at 12m/s, when the driver’s reaction time is 0.5s and they see a child run into the road?



    Additional Information:



    Car Mass: 900Kg.



    Braking Force: 2000N.



    Calculations:



    Part 1.  Reaction (Thinking) Distance:



    Distance = speed x time.



    d = v x t.



    Therefore, d = 12m/s x 0.5s



    Thinking Distance = 6m.



    Part 2.  Braking distance calculation:



    F x d = 1/2 x m x v2



    Transposed:



    d = (m x v2)/f x (1/2)



    d = (900 x 122)/2000 x (1/2)



    Braking Distance = 32 metres.



    Therefore, the total stopping distance is:



    Stopping distance = Reaction distance + Braking distance.



    Stopping distance = 6 + 32.



    Answer: 38m


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