Question

In 1974 the speed limit on highways in the United States was reduced to 55 miles per hour in order to save fuel. In the first 12 months after the change, the rate of highway fatalities dropped 15 pereent, the sharpest one-year drop in history. Over the next 10 years, the fatality rate declined by another 25 percent. It follows that the 1974 reduction in the speed limit saved many lives. Which one of the following, if true, most strengthens the argument? (A) The 1974 fuel shortage cut driving sharply for more than a year. (B) There was no decline in the rate of highway fatalities during the twelfth year following the reduction in the speed limit. (C) Since 1974 automobile manufacturers have been required by law to install lifesaving equipment, such as seat belts, in all new cars. (D) The fatality rate in highway accidents involving motorists driving faster than 55 miles per hour is much higher than in highway accidents that do not involve motorists driving at such speeds. (E) Motorists are more likely to avoid accidents by matching their speed to that of the surrounding highway traffic than by driving at faster or slower speeds.

Short answer

Option (D) most strengthens the argument.

Step-by-step solution

Analyze the Argument

The argument suggests that the reduction of the speed limit in 1974 led to a decrease in highway fatalities. It is based on the correlation between the speed limit change and the observed reduction in fatalities.

Identify Additional Evidence Needed

To strengthen the argument, we need evidence that directly links the reduction in speed limit to the decrease in fatalities, minimizing the contribution of other factors.

Examine Each Option

- Option (A) suggests a reduction in driving due to fuel shortage. - Option (B) refers to a later period with no change in fatality rates. - Option (C) presents the introduction of safety equipment in cars. - Option (D) highlights a higher fatality rate for speeds over 55 mph. - Option (E) discusses speed matching as a strategy to avoid accidents.

Choose the Most Relevant Option

Option (D) strengthens the argument by showing that accidents at speeds above 55 mph result in a higher fatality rate, directly supporting that reduced speeds could lower fatalities.

Key concepts

Understanding Argument Analysis

When we talk about argument analysis, we’re referring to the process of breaking down an argument into its core components to better understand its structure and evaluate its validity. In the given exercise, the argument asserts that the reduction of the speed limit in 1974 led to a decrease in highway fatalities. This conclusion is based on the observed correlation between the speed limit change and the reduction in fatalities.
Breaking down such an argument involves identifying its premises—the statements or facts that support the conclusion. Here, one premise is the observed reduction in highway fatalities following the speed limit change. Another key step in argument analysis is considering alternative explanations or factors that might affect the outcome. This helps in determining whether the causal link purported by the argument holds strong or is merely a coincidental relationship.

• Identify premises supporting the conclusion.
• Determine if the conclusion logically follows from the premises.
• Consider other potential explanations or contributing factors.

This structured approach equips you with the tools to critically assess arguments, making it an integral part of logical reasoning.

Exploring Strengthening Arguments

Strengthening an argument means providing additional support or evidence to bolster the main claim. When an argument is strengthened, it becomes more convincing and credible to its audience. In our exercise, the focus is on strengthening the argument that reducing the speed limit saved lives.
To achieve this, we search for pieces of evidence that directly correlate the speed reduction to the decline in fatalities, thereby eliminating or reducing the influence of alternative factors. In this context, Option (D) does the job well by highlighting that accidents at speeds above 55 mph tend to have a higher fatality rate. This insight directly supports the argument by suggesting that lower speeds inherently lead to safer driving conditions.

• Provide evidence that directly supports the conclusion.
• Minimize the impact of alternative explanations.
• Enhance credibility through relevant and solid data.

By focusing on strengthening arguments, one can turn a plausible claim into a well-substantiated conclusion, vital for persuasive logical reasoning.

The Role of Critical Thinking

Critical thinking is the disciplined process of actively analyzing, synthesizing, and evaluating information gathered from various sources. It involves questioning assumptions, recognizing biases, and stepping beyond emotionally driven reasoning to make informed decisions.
In our exercise, applying critical thinking involves assessing the provided options with the goal of validating the central argument. Option (D) was identified as the strongest, supporting the notion that reduced speed limits save lives by citing higher fatality rates at speeds over 55 mph. Critical thinking invites us to ask—does this evidence adequately link lower speeds to fewer fatalities? What further data could support or refute this claim?

• Challenge and test premises and conclusions.
• Identify any cognitive biases or emotion-driven reasoning.
• Remain open to revising opinions based on new evidence.

Engaging in critical thinking ensures that you not only accept conclusions at face value but also understand the deeper rationale behind them, a valuable skill for any aspiring logical reasoner.

Preparing for the LSAT with Logical Reasoning

For many aspiring lawyers, the LSAT is a critical step. It tests your ability to think critically, reason analytically, and evaluate arguments effectively. The Logical Reasoning section, in particular, is designed to assess these skills, requiring you to dissect and engage with complex arguments.
Successful LSAT preparation involves familiarizing yourself with various question types and weaving logical reasoning into your practice. The given exercise is a classic example of what you might encounter. You are tasked with analyzing an argument that posits a relationship between speed limits and safety outcomes, as well as evaluating which pieces of evidence best support this link.

• Gain familiarity with common LSAT question types.
• Develop a methodical approach to argument analysis and evaluation.
• Practice regularly to hone critical thinking and analytical skills.

With diligent practice and an understanding of logical reasoning principles, you can approach your LSAT preparation with confidence, equipped to tackle a range of analytical challenges.