Increase in particle number emissions from motor vehicles due to interruption of steady traffic flow

Document Type

Journal Article

Publication Date


Subject Area

operations - traffic, infrastructure - vehicle, policy - congestion, mode - bike, mode - pedestrian, mode - pedestrian


Traffic flow, Traffic congestion, Red interval (Traffic signal cycle), Pollutants, Pedestrian crossings, Particles, Line source models, Gridlock (Traffic), Emissions, Crosswalks


We assess the increase in particle number emissions from motor vehicles driving at steady speed when forced to stop and accelerate from rest. Considering the example of a signalized pedestrian crossing on a two-way single-lane urban road, we use a complex line source method to calculate the total emissions produced by a specific number and mix of light petrol cars and diesel passenger buses and show that the total emissions during a red light is significantly higher than during the time when the light remains green. Replacing two cars with one bus increased the emissions by over an order of magnitude.


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