Braking and Stopping    Two important factors that influence the distance you take to stop a car are how quickly you react to danger and the speed at which you are traveling.    The average reaction time (from the time driver sees danger to when he/she applies the brakes) is two seconds. Reaction time is affected by the driver's levels of tiredness, alcohol and concentration .    Braking distance ( the distance travelled after the driver has applied the brakes) depends on factors such as your speed, type of brakes, type pressure and tread , vehicle weight, wind speed, slope  of the road, surface smoothness and the driver's braking technique. Remember: As your speed doubles, your total stopping distance more than doubles.    At 60km/hr a vehicle will travel 34 meters while the driver is reacting to the danger, and another 21 meters before the car comes to a stop. Total stopping distance is 55 meters.    Total stopping distances shown in the graph are for vehicles with good brakes, on a dry smooth level road surface, and fitted with good tyres with the correct depth of tread. If I am driving at 70 km/hr, the distance I travel after I apply the brakes is about   _  .
39m 28m 70m 67m