More pedestrian injuries occur at crosswalks marked by both striping on the roadway and flashing lights than occur at crosswalks not so marked. Obviously these so-called safety features are a waste of taxpayer money.
Summarize Argument: Phenomenon-Hypothesis
The author concludes that the crosswalk safety features are a waste of money because more pedestrian injuries occur at crosswalks with these features than at crosswalks without them.
Identify and Describe Flaw
The author compares the number of injuries at crosswalks with safety features and crosswalks without them. He assumes that these crosswalks are similar to one another in all relevant ways, but there could be some important differences between them. For example, maybe far more people cross at the crosswalks with safety features. Or maybe these crosswalks are more dangerous in the first place and the safety features make them much safer, even though more injuries still occur at them.
A
fails to consider that crosswalks marked by both striping and flashing lights are marked in this way precisely because they are the most dangerous ones
If the crosswalks got safety features because they were the most dangerous, there would likely be even more injuries without the features. Even though the safety features haven’t completely eliminated injuries, the author can’t conclude that they’re a waste of money.
B
takes for granted that safety features that fail to reduce the number of injuries are a waste of taxpayer money
The author never claims that the safety features “fail to reduce the number of injuries,” just that more injuries occur at crosswalks with the safety features.
C
presumes that there are less expensive features that will reduce the number of pedestrian injuries just as effectively as striping and flashing lights
The author doesn’t propose any alternative measures for reducing injuries. He never assumes that less expensive features will be as effective, he just suggests that the current features aren’t effective enough.
D
takes for granted that crosswalks with both striping and flashing lights have no other safety features
The author only addresses striping and flashing lights, but he never assumes that these are the only safety features at crosswalks.
E
fails to consider that, in accidents involving pedestrians and cars, the injuries to pedestrians are nearly always more serious than the injuries to occupants of cars
The author only addresses pedestrian injuries. How these injuries compare to drivers’ injuries is irrelevant.