‘How much extra carbon dioxide was emitted because of the cyclist?’ asks A-Level exam paper

We were pointed in the direction of a question on this A-level physics exam paper from Edexcel today. The question is about how much extra carbon dioxide is emitted as a result of cars ‘queuing’ behind a cyclist on a narrow rural road.

Carlton Reid, who plans on featuring the question in his upcoming book Bike Boom says it was brought to his attention by his daughter. He says it is a prime example of the ‘insidious’ trope that cyclists cause air pollution.

Here’s the question in full.

It strikes us that it would be ten long minutes for the cyclist with three cars queued up behind.

We did wonder whether the final answer punchline was that carbon dioxide emissions would be higher once the cyclist had become a motorist. However, according to the answers (and somewhat miraculously, also according to our own calculations before we found those answers), this is not the case.

A possible follow-up question could perhaps have been: ‘How many of these motorists need to get on their bikes before carbon dioxide emissions are reduced?

We’d also quite like to see a similar question for an urban location where average driving speeds are significantly lower even without one of those pesky cyclists causing pollution by holding everyone up.