The thinking distance can also be affected if the driver is: tired or not concentrating, under the influence of alcohol, under the influence of drugs or some medicines, poor visibility for example rain or fog, age and health of driver and distractions e.g. mobile phones and sat-nav.
The other very important factor that affects the thinking distance is the speed of the car. A high speed will increase both the thinking distance and the braking distance and has a very marked effect on the stopping distances. Good drivers are aware of all of these factors and will always drive at sensible speeds for the conditions they are in. They will also keep far enough behind the car in front so they will have sufficient distance to stop in an emergency.
Other factors that affect reaction time are the effect of drugs and stimulants. Depressants will increase your reaction time, meaning that it will take longer for the driver to apply the brakes and in this longer time span the car covers more distance. Stimulants will give you a better reaction time meaning that the time for the driver to apply the brakes is shortened. In this smaller amount of time the car travels less distance. The main drug people take before driving is alcohol. Even consuming under the legal limit will affect your reaction time because alcohol is a depressant; as stated above depressants will increase your reaction time, therefore increasing your thinking distance.
The health and age of the driver will also affect your reaction time. As you get older your reaction time increases, meaning older drivers tend to have a longer thinking distance than that of younger drivers. Also if you’re living a healthy lifestyle and your profession includes having a fast reaction time such as an athlete your reaction time will be considerably faster than that of an unhealthy person. Tiredness will also affect your reaction time, the reason being that if you are tired you have less energy to concentrate on driving, thus the reason for having signs on the motorway stating “Tiredness Can Kill”. Distractions such as mobile phones, in car navigation systems, adjusting the stereo and large roadside billboards will also take the driver’s attention and will therefore affect the driver’s reaction time.
Both the law and the DVLA encourage drivers to not drive with factors that increase the thinking distance, in case of accidents. Examples of this are that the law states that drivers can not have: Men should drink no more than 21 units of alcohol per week (and no more than four units in any one day) and Women should drink no more than 14 units of alcohol per week (and no more than three units in any one day). If drivers are caught drink driving they will be giving a charge or even a driving ban if serious e.g. accident and unfortunate death of victim. Also in case of bad rain or even if you’re too tired for driving there are inns on long drive ways and hotels on the motorways so you can rest until fit to resume driving.
Braking distance increases with speed. This happens because if the car is travelling at a high speed it will take longer to stop than at a lower speed. This means that at a higher speed the vehicle has more time to cover more distance. For example if the vehicle is travelling at 70mph it takes longer to reach 0mph than if the vehicle were travelling at 40mph.
Many other factors can affect a vehicle’s Braking Distance. The condition of the vehicle’s tyres and brakes has an effect on when the car will stop. If the tyres are used and worn out they won’t grip as well onto the road meaning that the car will skid further making the braking distance longer. Obviously, if the brakes are in a better condition the braking distance will decrease, because the brakes will work better. The condition of the roads will also have a significant effect on the vehicles Braking Distance. For example if the roads were wet or icy the breaking distance would increase, because the tyres can’t grip the roads properly, making the vehicle skid further the braking distance longer. Other factors include making the mass of the car and the aerodynamics of the car.
I believe that the data drawn from the graph is not very reliable because they have not tested for other factors; they have only tested for speed and as I already explained speed is not the only factor than can alter both thinking and braking distance.
But I believe that the data from the graph is valid because as a general guide the data is correct. From the data given we can draw to the conclusion that the faster a vehicle is travelling, the longer its overall braking distance will be. It also shows that as thinking distance increases braking distance increases along with it, therefore meaning that overall stopping distance increases also.
Tas is correct. When asked about Braking Distance he states “surely it depends on the speed of the car and other things” There are many other factors which can affect how long it takes to brake. Including the condition of the tyres; the condition of the brakes; the condition of the roads; the mass of the vehicle and the aerodynamics of the car.
Tas investigated if other factors rather than speed can affect your overall stopping time. The graph that I have made from the data given to me on the Highway Code website clearly shows that the faster you are travelling, the longer your Thinking Distance is. It also shows that the greater your speed the longer your Braking Distance. Because the formula for working out the Overall Stopping Distance is to add both of theses distances together, it means that it also increases with the speed at which the car is travelling at. But the graph does not show the overall stopping distance when it is affected by factors other than speed. But it is a fact that speed is not the only factor that affects the overall stopping distance time as I have already stated.
Many people believe that the speed limits on our roads should be lowered to help lower accidents on the road, thus saving lives. Others believe that they should remain the same, so that they can get to places faster and not have to worry about speeding offences.
An argument for lowering speed limits made by the British Medical Journal in 2000 “ The chance of a pedestrian being seriously injured or killed if struck by a car is 45%if the car is travelling at 30mph but only 5% at 20mph. Where as Sam would argue that “Isn’t it bad driving that kills people and not speed?” This is true but the speed the car is travelling at will have a huge affect on what damage is done when hit. An article from The Independent magazine in 2005 states “Opponents of tighter speed limits say that measures can be counter productive, forcing drivers to spend more time concentrating on scouring the horizon for speed cameras and keeping an eye on their speedometers, rather than concentrating on the road in front of them.” I agree with this on some levels. Where as the government’s road safety advisors claim “Speed limits in many towns and cities should be reduced to 20mph” Their report claims a default speed of 20mph in built up areas will help halve the number of deaths on Britain’s roads within the next few years. The study also called for greater enforcement of 20mph zones through a new generation of speed cameras. BBC, 2007.
Others argue that if speed limits were lowered then fuel economy would go up, meaning that cars will use less petrol to get to places. Thus saving the environment, by using less fossil fuels producing less carbon dioxide. But people argue that reducing the speed limit will cause more congestion on the roads, meaning that it will take longer to get to places and wasting more petrol.
