Critical Reasoning

The faster a car is traveling, the less time the driver has to avoid a potential accident, and if a car does crash, higher speeds increase the risk of a fatality. Between 1995 and 2000, average highway speeds increased significantly in the United States, yet, over that time, there was a drop in the number of car-crash fatalities per highway mile driven by cars.

Which of the following, if true about the United States between 1995 and 2000, most helps to explain why the fatality rate decreased in spite of the increase in average highway speeds?

(A) The average number of passengers per car on highways increased.

(B) There were increases in both the proportion of people who wore seat belts and the proportion of cars that were equipped with airbags as safety devices.

(C) The increase in average highway speeds occurred as legal speed limits were raised on one highway after another.

(D) The average mileage driven on highways per car increased.

(E) In most locations on the highways, the density of vehicles on the highway did not decrease, although individual vehicles, on average, made their trips more quickly.

[spoiler]OA:B
[/spoiler]
Why D is wrong?

rate of fatality = number of fatalities/miles driven . When miles increase,the rate should decrease.

Thanks

OA - B ?

Mo2men wrote:Why D is wrong?

rate of fatality = number of fatalities/miles driven . When miles increase,the rate should decrease.

Thanks

D: The average mileage driven on highways per car increased.
Consider the following case:
In 1995, 10 cars each drive an average of 10 miles, for a total of 100 miles.
In 2000, 10 cars each drive an average of 10.1 miles, for a total of 101 miles.
Here, the total number of miles is virtually the same in each case.
But according to the passage, the 10 cars in 2000 are driven significantly FASTER.
The result should be an INCREASE in the number of fatalities per mile.
Thus, D does not explain why there was a DROP in the number of fatalities per mile.
Eliminate D.