REFLECTING ON THE ACTIVITY
AND THE CHALLENGE

Safe driving requires the ability to stop safely. Some people think that if you double your speed, the car will require double the stopping distance. You now know that it will take more than double the stopping distance— it is closer to four times the stopping distance! You should be able to explain the importance of stopping distance as it relates to speed. You should understand why slowing down is so helpful in terms of stopping distance and what will happen to the required stopping distance if you decrease your speed by one half.

1. A student measured the stopping distance of her car and recorded the data in the chart below. Plot the data on a graph and describe the relationship that exists between initial speed and stopping distance.

2. Below are the stopping distances in relation to speed graphs for two cars. Compare qualitatively (without using numbers) the stopping distances when each car is going at a slow speed and then again at a higher speed. Which car is safer? Why? How did you determine what "safer" means in this question?

3. A car is able to stop in 20 m when traveling at 30 mph. How much distance will it require to stop when traveling at:

a) 15 mph? (half of 30 mph)

b) 60 mph? (twice 30 mph)

c) 45 mph? (three times 15 mph)

d) 75 mph? (five times 15 mph)

4. A car traveling at 10 m/s requires a stopping distance of 30 m. If the driver requires 0.9 s response time, what additional distance will the car travel before stopping?

5. Consult the information for the 1998 Corvette Convertible found on page T56 of this book. This shows the stopping distance from Road & Track magazine. How far would you expect this car to travel until coming to rest when brakes are applied at a speed of 30 mph?

6. Use the information on page T55. Find the braking distances for 50 mph and 25 mph. Create a graph using the different braking distances. Plot the speeds on the horizontal axis and the stopping distances on the vertical axis.

7. Does the braking information on page T55 include the driver's response time? Who should let the consumer know about this-the information sheet or a driver training manual?

8. Apply what you learned from this activity to write a statement explaining the factors that affect stopping distance. What do you now know about stopping that will make you a safer driver?