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?
The response distance is the distance you travel from a hazard detection point until you start to brake or turn.
Response distance is affected by:
Car speed (proportional increase):
2 x higher speed = 2 x longer response distance.
5 x higher speed = 5 x longer response distance.
Your response time.
Usually 0.5 - 2 seconds.
For 45 - 54 year olds the best response time in traffic.
18-24 year olds and people over 60 have the same reaction time in traffic. Young people have sharper senses, but older people have more experience.
Response distance can be reduced by -
Expectation of casualties.
Readiness.
Response distance can be increased by -
Decision-making necessity (e.g., whether braking or steering out of the way).
Alcohol, drugs and drugs.
tiredness .
Easy Method: Calculate the response distance
Formula: Remove the last digit quickly, multiply the response time, and then 3.
An example of a 50 mph speed calculation and a second response time:
50 mph ⇒ 5
5 * 1 * 3 = 15 meter response distance
More accurate method: Calculate response distance
Formula: d = (s * r) / 3.6
d = response distance in meters (to be calculated).
s = speed per hour.
r = response time in seconds.
3.6 = Fixed figure for converting km / h to mph.
An example of a 50 mph speed calculation and a second response time:
13.9 meters response distance = 3.6 / (50 * 1)
Braking Distance:
Braking distance is the distance the car travels from the point where you start braking until the car stands still.
Braking distance is affected by:
Vehicle Speed (Square Increase; "Raised to 2"):
2 x higher speed = 4 x longer braking distance.
3 x higher speed = 9 x longer braking distance.
The road (gradient and conditions).
Rush.
Brakes (mode, braking technology and some brake wheels).
Calculate the braking distance:
Reliable braking distance calculations are very difficult to achieve as road conditions and tire grip can vary greatly. For example, the braking distance may be 10 times longer when there is ice on the road.
Easy Method: Calculate the braking distance
Conditions: Good and dry road conditions, good tires and good brakes.
Formula: Zero the velocity, multiply the figure by itself and then multiply by 0.4.
The figure 0.4 is taken from the fact that the braking distance of 10 km / h in dry road conditions is about 0.4 meters. This is calculated by researchers who measure the braking distance. Square with the speed increase.
Example of 10 km / h speed calculation:
10 mph ⇒ 1
1 * 1 = 1
1 * 0.4 = 0.4 meters distance braking
Example of 50 km / h speed calculation:
50 mph ⇒ 5
5 * 5 = 25
25 * 0.4 = braking distance of 10 meters
More accurate method: Calculate braking distance
Conditions: Good tires and good brakes.
d = braking distance in meters (to be calculated).
s = speed per hour.
250 = a permanent figure that is always used.
f = coefficient of friction, about 0.8 on dry asphalt and 0.1 on ice.
Calculate the stopping distance using these easy methods
It's summer and the road is dry. You drive at 90 mph with a car with good tires and brakes. Suddenly you notice a road hazard and braking forcefully. How long is the stopping distance if your response time is one second?
The stopping distance is the reaction distance + the stopping distance. First, we calculate the response distance:
90 mph ⇒ 9
27 feet Response distance = 9 * 1 * 3
Then we calculate the braking distance:
90 mph ⇒ 9
9 * 9 = 81
32 meters braking distance = 81 * 0.4
The two distances are now combined:
Stop distance of meters = 27 + 32
Clarification is important about calculations
The different methods provide different answers. Which should I use?
Use whatever you want. The differences are so small that they will not affect your theory test, since the margins between the alternatives are quite large.
So if the alternatives are 10, 20, 40, 60, it doesn't matter if you get 10 meters in one method and 12.5 meters.
With another - both are of course closest to 10, which is the correct answer
The response distance is the distance you travel from a hazard detection point until you start to brake or turn.
Response distance is affected by:
Car speed (proportional increase):
2 x higher speed = 2 x longer response distance.
5 x higher speed = 5 x longer response distance.
Your response time.
Usually 0.5 - 2 seconds.
For 45 - 54 year olds the best response time in traffic.
18-24 year olds and people over 60 have the same reaction time in traffic. Young people have sharper senses, but older people have more experience.
Response distance can be reduced by -
Expectation of casualties.
Readiness.
Response distance can be increased by -
Decision-making necessity (e.g., whether braking or steering out of the way).
Alcohol, drugs and drugs.
tiredness .
Easy Method: Calculate the response distance
Formula: Remove the last digit quickly, multiply the response time, and then 3.
An example of a 50 mph speed calculation and a second response time:
50 mph ⇒ 5
5 * 1 * 3 = 15 meter response distance
More accurate method: Calculate response distance
Formula: d = (s * r) / 3.6
d = response distance in meters (to be calculated).
s = speed per hour.
r = response time in seconds.
3.6 = Fixed figure for converting km / h to mph.
An example of a 50 mph speed calculation and a second response time:
13.9 meters response distance = 3.6 / (50 * 1)
Braking Distance:
Braking distance is the distance the car travels from the point where you start braking until the car stands still.
Braking distance is affected by:
Vehicle Speed (Square Increase; "Raised to 2"):
2 x higher speed = 4 x longer braking distance.
3 x higher speed = 9 x longer braking distance.
The road (gradient and conditions).
Rush.
Brakes (mode, braking technology and some brake wheels).
Calculate the braking distance:
Reliable braking distance calculations are very difficult to achieve as road conditions and tire grip can vary greatly. For example, the braking distance may be 10 times longer when there is ice on the road.
Easy Method: Calculate the braking distance
Conditions: Good and dry road conditions, good tires and good brakes.
Formula: Zero the velocity, multiply the figure by itself and then multiply by 0.4.
The figure 0.4 is taken from the fact that the braking distance of 10 km / h in dry road conditions is about 0.4 meters. This is calculated by researchers who measure the braking distance. Square with the speed increase.
Example of 10 km / h speed calculation:
10 mph ⇒ 1
1 * 1 = 1
1 * 0.4 = 0.4 meters distance braking
Example of 50 km / h speed calculation:
50 mph ⇒ 5
5 * 5 = 25
25 * 0.4 = braking distance of 10 meters
More accurate method: Calculate braking distance
Conditions: Good tires and good brakes.
d = braking distance in meters (to be calculated).
s = speed per hour.
250 = a permanent figure that is always used.
f = coefficient of friction, about 0.8 on dry asphalt and 0.1 on ice.
Calculate the stopping distance using these easy methods
It's summer and the road is dry. You drive at 90 mph with a car with good tires and brakes. Suddenly you notice a road hazard and braking forcefully. How long is the stopping distance if your response time is one second?
The stopping distance is the reaction distance + the stopping distance. First, we calculate the response distance:
90 mph ⇒ 9
27 feet Response distance = 9 * 1 * 3
Then we calculate the braking distance:
90 mph ⇒ 9
9 * 9 = 81
32 meters braking distance = 81 * 0.4
The two distances are now combined:
Stop distance of meters = 27 + 32
Clarification is important about calculations
The different methods provide different answers. Which should I use?
Use whatever you want. The differences are so small that they will not affect your theory test, since the margins between the alternatives are quite large.
So if the alternatives are 10, 20, 40, 60, it doesn't matter if you get 10 meters in one method and 12.5 meters.
With another - both are of course closest to 10, which is the correct answer
