LSAT 137 | Section 3 | Logical Reasoning: Q1

LR Question 1 Explanation

QUESTION TEXT: A research study revealed that, in most cases, once…

QUESTION TYPE: Paradox

FACTS: Widening and extending highways near urban areas tends to increase delays and congestion for motorists.

ANALYSIS: Obviously, roads don’t directly cause congestion. So, we have to find some factor that increases along with roads, and causes congestion.

As with much on the LSAT, real life helps here: it’s frequently the case in the real world that building roads causes more people to drive, which leads to traffic congestion. Using outside knowledge to form hypotheses helps you more easily predict answer and solve questions quickly.

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1. CORRECT. Say the roads are widened 20%. If the roads attract “many more” motorists, maybe there are 40% more motorists. That would worsen delays, and explain the paradox.
2. If the population has “leveled off”, that means motorists are no longer increasing. So we would expect any road expansion to reduce congestion, as there are more roads per motorist.
3. This makes the situation more confusing. Accidents cause delays and congestion. And this answer says increasing the number of roads (per citizen) causes fewer accidents per citizen. So why did congestion increase? If this answer had said wider roads cause more accidents then it could have been right.
4. This tells us nothing: we don’t know if the roads “near urban areas” are rural. They might just be “suburban”. And we don’t know the effects of trucks, or farmers’ vehicles. Or why expansion would have a different effect when those are present. (The trucks and farm vehicles would have been present before the expansion.)
5. So? This question isn’t about urban traffic. It’s about roads near urban areas.