PrepTest 142, Section 2, Question 21
A government study indicates that raising speed limits(60 more words not shown)
Which one of the following(10 more words not shown)
- AUniform national speed(7 more words not shown)
- BTraffic laws applying(9 more words not shown)
- CA uniform national(20 more words not shown)
- DLong-standing laws that(8 more words not shown)
- EAny measure that(9 more words not shown)
Reading the argument
Raising a speed limit reduces accidents? That might sound surprising, but the study gives us that result. Perhaps matching the flow of traffic helps; we don't need to establish the mechanism to accept the stated finding.
My concern is the jump from an average to one limit for all these roads. Even two level, straight stretches could differ. Imagine one crossing open farmland and another bordered by trees, with poor visibility and deer near the road. The same average speed doesn't obviously settle the best limit for each stretch.
What we’re looking for
We're asked for a principle that helps justify the recommendation. My first thought is a rule supporting use of the average as a common standard. The choices need to give the author a reason to adopt the proposed limit, while staying connected to the evidence actually offered.
Working the answers
- A
Limiting where a national rule may apply doesn't tell us what limit to set or why to raise it. The proposal already concerns high-speed roadways. A says nothing that turns the study's result into a reason to adopt this particular standard.
- B
This supports uniformity in general, but it doesn't tell us to choose 75 miles per hour. It also speaks to high-speed roadways broadly, while the proposal concerns their level, straight stretches. The more direct justification would connect the study's claimed benefit with implementing the proposed change.
- C
This makes roughly equal average speeds a requirement for a uniform limit. Even if that requirement were met, C wouldn't say we should adopt the limit. Also, an overall tendency toward 75 doesn't establish that every relevant roadway has roughly the same average. C gives a restriction without supplying the positive reason to act.
- D
We aren't told that the existing limits are long-standing and widely violated, and criticizing an old law wouldn't by itself justify this specific replacement. We need a principle supporting the proposed measure on the facts given.
- ECorrect
This uses the study's safety finding rather than resolving the concern about averages directly. The argument says matching limits to actual average speeds reduces accidents. E tells us to implement measures with that benefit, providing a reason to set the proposed limit.
A principle that helps justify the reasoning needn't answer every question we could raise about unusual stretches of road. E directly connects the benefit the author cites—fewer accidents—to the recommendation to act.
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