Speedwatch volunteers – helping to keep you safe


More speed means more severity

The greater the impact speed, the greater the force added into any crash. This force can translate into damage to people. More speed means more severity of crash.

Hit by a car at 20 mph, 1 out of 40 pedestrians will be killed, 97% will survive

Hit by a car at 30 mph, 2 out of 10 pedestrians will be killed, 80% will survive

Hit by a car at 35 mph, 5 out of 10 pedestrians will be killed, 50% will survive

Hit by a car at 40 mph, 9 out of 10 pedestrians will be killed, 10% will survive

Speed may not be the main cause of the crash, but it will certainly decide the level of severity of the crash.

How fast is too fast?

The legal speed limit isn’t an indication of a safe speed for all times and conditions. Use this as a guide but you still need to make a continuous judgement about how much below the limit you need to be at any one time.

Street lights mean 30

If you have difficulty in spotting what the speed limit is for the road you are on, the best way is to assume it’s a 30mph limit until a sign tells you other wise, particularly in urban / built up areas..

The Highway Code sets out clearly that if there are no speed limit signs but there are street lights, then the limit is usually 30mph.

“If the road in question has a system of street lighting, with no speed limit repeater signs, the limit is usually 30mph. The traffic authority is not allowed to place 30mph repeater signs on these roads. The system of street lighting in an area should be sufficient evidence of 30mph limit” – The Highway Code.

How to stick to the 30mph limit – 3rd in 30

If you have difficulty staying at 30mph in a 30mph limit, try driving in 3rd gear. The sound of the engine will tell you if you are likely to be going above 30mph – just at the point you think of changing to 4th gear, check your speed, it’s likely to have crept just above 30mph. A similar thing can be achieved in an automatic car too.

In the same way, you could try 4th in 40. However, it doesn’t quite work in 20mph zones – so here you would need to be extra vigilant over your speed.


Aside from the physical upset, hurt and turmoil of causing or being involved in a crash you could end up with a fine, points on your licence, disqualification, even a prison sentence and a criminal record. Even if you are driving within the speed limit but deemed to be driving at an inappropriate speed when you crash, you can still face prosecution. Don’t run the risk, See the Hazards, don’t take speed to the limit – read the road.

What is appropriate speed?

Clearly all drivers must stick within posted speed limits – to exceed these is illegal and can result in prosecution. This is ‘excessive speed’.

The challenge for all drivers, however, is to estimate how fast they should go up to the limit, and still be able to stop in an emergency. This is ‘appropriate speed’.

A definition of appropriate speed is ‘travelling at a speed that allows you to stop in the distance you can see to be clear’ and this will vary from one road to another and one hour to the next. On urban roads the challenge is greater due to the constant appearance of new hazards (and road users) and that these hazards changing continually.

An example of this is driving past a school, in a 30mph limit, on an early, bright and dry August morning. 30mph might be quite safe as the conditions are good and there are few others around. However, when driving past the same school in mid-December, at 3pm on a wet road with lots of parents and children around, even 25mph may be too fast – and wholly inappropriate.

The best advice is to keep your wits about you and expect the unexpected.

  • Expect a vehicle with a right hand indicator to drive straight on
  • Expect the child on the path to forget about the road and dash out suddenly
  • Expect there to be a motorcyclist in your blind spot
  • Expect the green traffic light to change as you get close to it
  • Expect the driver approaching a junction to pull out in front of you without looking
  • Expect cyclists, especially young an novice cyclists, to wobble in the road as you get near to them
  • Expect the teenager not to be concentrating on the road because their social life is more important to them at that time.

This approach to driving will help take the stress of having to ‘suddenly’ deal with an emergency situation. If you half-expect it, you have already half-reacted to it. The best action if you expect something to happen is to slow down and give yourself time and distance to do something about it in.