3a)
(REF: The Highway Code)
3b) I have plotted my graph and I have come up with a trend line. I am going to use my trend line to work out the stopping distance of the car travelling at 80mph. The equation of my trend line is:
Stopping distance = 0.0154(speed)2 + 0.2913(speed)
Stopping distance = 0.0154(80)2 + 0.2913(80)
Stopping distance = 0.0154(6400)+ 0.2913(80)
Stopping distance = 0.0154×(6400)+ 0.2913×(80)
Stopping distance = 98.56 + 23.304
Stopping distance = 121.864
Therefore the stopping distance when the car is travelling at 80mph is 121.864m.
4) New laws require car designs that minimise injury to pedestrians involved with vehicles.
Car design for Safety
Below is a diagram of a new car and some of its features which make the car safer.
Modern cars are built with
Modern cars are built with many features designed to improve safety. A moving car has kinetic energy. If a car is involved in a collision it has to lose kinetic energy very quickly. Modern cars have safety features that absorb energy when the cars stop.
Active safety features directly improve the safety of a car and include:
- ABS Brakes (anti lock braking system) give vehicle stability and maintain steering during hard braking in slippery conditions. Hard continuous pressure is needed to activate anti lock brakes. The driver gets the maximum braking force without skidding and can still steer the car. The driver does not necessarily stop more quickly.
- Traction control stops the wheels on a vehicle from spinning when it accelerates rapidly. It gives maximum grip and stability on the road during acceleration.
- A Safety cage is a rigid frame that prevents the car from collapsing and cruising the occupants in a roll over crash
- Crumple zones at the front and rear ends of the car keep damage away from the internal safety cage. They absorb energy when a vehicle stops because they change shape.
- A seatbelt stretches and slows a person down more slowly.
- An airbag inflates and prevents the driver and passengers from hitting their head on rigid areas of the vehicle in side impact collisions. It absorbs some of the persons kinetic energy by squashing up around them.
Passive safety features indirectly increase the safety of a car. They help a driver to concentrate on the road and reduce driver tiredness. They include:
- Electric windows open and close quickly at the push of a button leaving the driver to concentrate on driving
- A Cruise control system accelerates to a fixed speed irrespective of the load in the vehicle or the gradient of the road. It is less tiring on long motorway trips and avoids ‘lead-foot syndrome’, where the driver rests their foot too hard on the accelerator pedal and inadvertently speeds up.
- Paddle shift controls allow the driver to operate gears, lights, stereo and wipers without taking their hands off the steering wheel or their eyes off the road.
- Adjustable seating allows the drivers seat to be in a safe, comfortable position
Active safety features have more immediate affect of saving lives in a accident whereas passive safety features contribute to safe driving but do not directly affect the safety of a car driver and passengers in an accident.
The equation is:
Kinetic energy lost = work done by brakes
1 mv2= fxd
2
where m = mass of car
v = speed of car before braking
If f increases, d decreases and the braking distance decreases.
(REF: Collins Science Additional)
5a)
Crash barriers are a resistance safety fence which is designed to separate traffic from vulnerable areas such as buildings, walls, machinery and pedestrian areas. It offers an effective, flexible barrier whilst minimising damage to vehicles.
5b) Other ways in which safety of roads have been improved are:
Speed humps are intended to slow you so they reduce the risk of accidents.
Speed cameras will flash if you go over the speed limit so therefore people will drive safely.
Speed limits- You must not exceed the maximum speed limits for the road and for your vehicle. Street lights usually mean that there is a 30mph speed limit there are signs showing another limit.
Traffic lights
FLASHING LIGHTS
(REF: )
ROAD MARKINGS ACROSS THE ROAD
ROAD MARKINGS AT A BOX JUNCTION
Do not enter the box unless your exit road or lane is clear, except to turn right.
ROAD MARKINGS ALONG THE ROAD
REF:
ROAD SIGHNS
SIGNS GIVING ORDERS
Always obey traffic signals, road signs and the signals given by police officers, traffic wardens and school crossing patrols.
Circular signs usually give orders, triangular signs give warnings and rectangular signs give information.
These signs are mostly circular
Those with blue circles usually tell you what you must do.
Signs with red circles usually tell you not to do something
REF:
