# Speed and Stopping Distances

## Presentation on theme: "Speed and Stopping Distances"— Presentation transcript:

Speed and Stopping Distances
Slide 1 Print out these notes pages. What to do, questions and facts are in plain type, likely answers in italic. X=click to advance For this lesson, you will need plenty of space – go into a hall or playground. You will also need two long pieces of string, one 12 metres long and the other 23 metres long. Introduce yourself. X This lesson is all about speed, how it affects you when you are walking or cycling. Being aware of the speed of the traffic and the distance it can take a car to stop may reduce your chances of being injured on the road.

How fast do these things normally travel?
Speed We measure speed in miles per hour mph 1 mile ≈ 1,600m or 1.6km 1 mph ≈ 1.6kph How fast do these things normally travel? Slide 2 X Explain that we are going to be talking about speed today. We measure speed in MPH - what does this mean? (Miles per hour or we could use kilometres per hour – the distance something travels in a certain amount of time). X X I am going to show you some pictures and I want you to guess how fast these things can travel , at a normal speed, without breaking the law! (Take 3 or 4 guesses for each slide then reveal the answer).

600mph Slide 3 How fast can a passenger jet go? X 600mph

70mph Slide 4 How fast can a cheetah run (top speed)? X 70mph

70mph Slide 5 How fast can an ordinary car go (legally in the UK)?
X 70mph

3mph Slide 6 How fast can you walk?
X 3mph on average, walking fairly fast.

30mph Slide 7 How fast can a moped go?
X 30mph – mopeds are limited to this speed, motorbikes with bigger engines can go faster.

20mph Slide 8 How fast can a cyclist go?
X 20mph on average – racing cyclists more than this.

Slide 9 As pedestrians – what does the word ‘Pedestrian’ mean? (It means a person walking) we need to be aware of some facts about vehicles and speed. The faster a vehicle is going the harder it will hit you if you are involved in a collision with it. In a collision between a car and a pedestrian the faster the car is going the more badly hurt the pedestrian will be! That’s why we have speed limits which are lower where there are most pedestrians about – what is the speed limit outside this school? (Take 2 or 3 answers, it’s usually 20 or 30mph – check beforehand if possible)

Hit by a vehicle at... Slide 10
X You may have seen the TV advert of the girl who is hit by a car

Hit by a vehicle at... 9 in 10 chance of being killed 1 in 5 chance
Slide 11 X At 40 miles per hour, that car has so much force that there is a 9 in 10 chance that someone will be killed. 1 in 40 chance of being killed

Hit by a vehicle at... 9 in 10 chance of being killed 1 in 5 chance
Slide 12 X At 30 mph, your chances are far greater. If your chances of being killed are 1 in 5, what are your chances of surviving the crash? (4 out of 5 or 80% as a percentage). 1 in 40 chance of being killed

Hit by a vehicle at... 9 in 10 chance of being killed 1 in 5 chance
Slide 13 X If the traffic speeds are brought right down to 20mph, which is often the case around schools, then there is just a 1 in 40 chance of being killed (so 97.5% chance of survival). If a car goes faster, is it going to take more time or less time to stop? (it will take more time to stop) We call the distance a vehicle travels from the time the driver decides to stop until it comes to a halt its ‘stopping distance’. We are going to now spend a bit of time thinking about stopping distances and what else affects the length of time that it takes to stop a vehicle. In an emergency – say if a child runs out in front of a car what sequence (explain word) of events has to happen before the car stops? 1 in 40 chance of being killed

Stopping distance is... Child runs out Driver sees child
Driver thinks ‘stop’ Foot on brakes Brakes work Car stops Slide 14 The sequence is X Child runs out X Driver sees child X Driver has to think about stopping the car X Driver needs to apply the brakes (put foot on brakes) X The brakes need to work X The car stops.

Stopping distance is... The distance a vehicle travels from the time the driver decides to stop until the vehicle actually stops moving. Slide 15 X The total stopping distance is the distance a vehicle travels from the time the driver decides to stop until the vehicle actually stops moving. X

Stopping distance is... Thinking distance Braking distance
Child runs out Driver sees child Driver thinks ‘stop’ Foot on brakes Brakes work Car stops Slide 16 All of this takes time! The car doesn’t stop instantly! Explain ‘Thinking Distance’ & ‘Braking Distance’ - the shorter the 2 sections are the quicker the car will stop! X Thinking distance is dependant on how fast the driver reacts to the situation - reaction time - get some children to try out ‘reaction’ cards, or to recite a times-table, with no distractions. All the time the driver is ‘thinking’ about stopping, the car keeps travelling – the slower the reaction the further the car travels! Remember at this point the driver still hasn’t yet applied the brakes & the brakes still need time to work before the vehicle will actually stop. X The Braking distance is the amount that the car travels once the driver starts to apply the brakes and keeps braking until the car stops completely. Explain that so far we have been talking about ideal conditions, with an alert driver in a car that’s in full working order on a dry, clear day. Discuss what might increase the thinking distance and the stopping distance – weather (bike brakes in wet), condition of the car, condition of the driver, children in the car distracting the driver! Get some children to try out the reaction cards again – this time ask the children to do it while reciting a times table etc., or reciting a times-table and being asked questions e.g. What did you have for breakfast etc.

Stopping distances... 20 30 40 50 60 70 3 car lengths – 12m mph
Slide 17 Get 6 children to stand up and walk (across the hall or go outdoors) to where they think a car would stop at 20mph – and stand still, no cheating! Then measure out the distance with string (marked in car lengths) - 6 metres thinking distance plus 6 metres braking distance gives a total of 12 metres or 3 car lengths. Are you surprised by how far this is? How much further do you think it would be at 30 mph? (Measure out the distances - 9 metres thinking distance plus 14 metres stopping distance gives a total of 23 metres or 6 car lengths. See how much further this is – it is almost double the stopping distance for only 10MPH faster!) Show distances chart for X 20mph X 30 X 40 X 50 X 60 X 70 Can you see the effect of the speed on how far it takes to stop the car? 70 mph 24 car lengths – 96m

...remember cars need time to stop!
Don’t take risks.... Slide 18 To finish, remember these points: X When we are out and about walking by the roads or riding on our bikes we need to be aware of the effect of speed on vehicles. X We need to understand that vehicles (including bicycles) can’t stop instantly – the driver needs time to react and the car needs time to stop! We need to be aware of the speed things are moving around us so we don’t take unnecessary risks – don’t run out or cross if there are cars coming – if something happens the car probably won’t be able to stop in time! Even at Zebra and green man crossings be extra careful – don’t start to cross until the cars have STOPPED! So BE CAREFUL and keep safe! ...remember cars need time to stop!