Requirements for zero impact vehicles

Authors

S. Hausberger, U. Uhrner, W. Stadlhofer - IVTTU Graz, N. Toenges-Schuller, C. Schneider - AVISO

Summary

The target of a conceptual study for FVV, [1] was to analyse the requirements of "zero impact vehicle (ZIV)" emission levels from an air quality perspective. We selected as zero impact definition “the road traffic contribution to air pollutants near roads shall be irrelevant compared to the WHO-2005 air quality guidelines, i.e. lower than 3% of these air quality (AQ) limits”. We have used unfavourable exhaust gas dilution situations to convert zero air quality targets into emission targets for total traffic. Dividing these total emission targets by the traffic volume yields the limit values for emissions per vehicle kilometre. We analysed different traffic situations, including motorways with high traffic volumes, dense urban traffic with a high proportion of cold starts and alpine roads with steep gradients and dynamic driving. The thresholds for vehicle emissions to achieve zero impact were calculated for possible worst-case combinations of traffic volumes, driving behaviour, road gradients and cold start shares. The analysis shows, that “zero AQ impact vehicles (ZIV) should not exceed NOx emissions of ca. 7mg/km for cars and 30 mg/kWh for HDVs in dense urban driving situations. For PN the current average Euro 6 vehicle already meets the ZIV targets in urban driving, which is in the range of 5E+11 #/km. In more demanding driving situations, such as alpine roads with steep gradients, much higher emissions per vehicle-km are possible without exceeding the zero impact targets, since much less vehicles per hour are passing such roads. In contrary, dense motorways need lowest emissions per vehicle-km due to the high number of vehicles. The sensitivity analysis was finally validated by detailed air quality simulations for different areas.