Unit 4 · Strengthening Arguments
Transport Speed Study — Parallel Mechanism Strengthener
Lesson 2 of 11
Harder strengtheners often use a different setting to prove the same logic — you follow the structure, not the topic keywords.
Parallel-mechanism strengtheners sit in the harder band of Selective argument questions; they catch students who pick emotionally relevant but logically weak options.
You must spot the underlying cause-and-effect claim (e.g. changing the environment changes behaviour) and recognise when evidence from another place proves that same pattern.
A policy or council argument claims X leads to Y. The correct support describes a different location or policy where improving conditions reduced the same kind of problem.
Best approach: Strip the argument to “If we do X, we get Y.” Test each option: does it show X→Y in any real example? Ignore topic overlap — matching logic beats matching words.
Question
The Department of Transport is considering a "Low Traffic Neighbourhood" scheme that blocks through-traffic on residential side streets to encourage walking and cycling. Opponents argue that this will simply move the pollution and traffic to the main boundary roads, making the air quality worse for people living there.
The Lead Planner replies: "This assumes that the total volume of traffic is a fixed 'liquid' that must go somewhere. In reality, traffic is 'elastic.' When you make driving less convenient and walking safer, a significant percentage of people choose not to drive at all. Improving the local environment actually 'evaporates' traffic rather than just moving it."
Which one of these statements, if true, most strengthens the Lead Planner's argument?
Select an answer to see the explanation.
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