Policy analyst: Those concerned with safeguarding public health by reducing the risk of traffic fatalities typically focus their efforts on automotive safety measures such as increasing seat belt use, reducing distracted driving, and improving automotive technology.
Conclusion
What would contribute the most to safeguarding public health is a reduction in total miles traveled on our roads.
Evidence
Traveling by car is itself a major risk factor.
Evaluate
Whenever we do Main Conclusion or Role, we specifically listen for upside-down arguments, where the Conclusion appears earlier than the Evidence.
The two dominant patterns on Main Conclusion are that the conclusion is - the First Sentence or - some Pivot / Rebuttal idea
The first sentence of this argument isn't the author's opinion, so it won't be the conclusion. Instead, it's an attribution: Those concerned with X typically focus their efforts on Y.
That would lead us to anticipate a Pivot / Rebuttal. Sure enough, we get the But to start the 2nd sentence. Is this claim an opinion from our author?
Yes! She's saying what she thinks would contribute the most to public health.
Is this claim Supported (as all conclusions must be)?
Yes, the last sentence is a "fact" that supports it.
Goal
Look for an answer that captures the meaning of the 2nd sentence. It might take on more language that feels like the Rebuttal: