Traffic management and emissions

The project consists of an evaluation of the effects on emissions of different traffic planning initiatives such as steady flow, bus lanes and bus priority in traffic. The difference between the rush hour traffic situation and the steady traffic flow shows reductions from the passenger car by 25–35 percent of HC and CO emissions and reductions by 10–25% of NO% emissions. The effect of bus lanes is a reduction by 5–12% of the NO% particulate emissions from the buses. The reduction will exceed 15–30%, if there is introduced bus priority in the traffic lights, which always gives the buses a green light. A comparison of the emissions from private passenger cars and buses per passenger and km shows that the HC and CO emissions are many times greater from private cars than from the buses. The NO% and particulate emissions are at about the same level, but highest from private cars in the inner city with a stop and-go traffic situation and many passengers in the buses. In suburban streets the emissions of NO% and particles per person and per km is highest from buses. The project shows a clear correspondence between travelling speed (travel length divided by trip time) and emissions from all vehicle types.