How Traffic Congestion Affects Local Air Quality
Launch library · evergreen read
Congested traffic forces vehicles to spend more time idling or moving at low, inefficient speeds, conditions under which engines typically produce more pollution per kilometre travelled than they would at a steady cruising speed on a clear, open road with little surrounding traffic to slow things down.
This means congestion does not simply waste time and fuel, it also concentrates vehicle emissions within a smaller area for longer, which is part of why air quality readings near heavily congested intersections and arterial roads tend to be noticeably worse than readings taken along less congested stretches nearby.
Measures that reduce congestion, from better signal timing to dedicated public transport lanes that keep buses moving freely, can therefore deliver an air quality benefit alongside the more obvious time savings, since smoother traffic flow generally means engines operating closer to their more efficient, lower emission range for a greater share of any given trip.