The importance of the category of light duty vehicles (LDV) has increased substantially over the past years. The LDV fleet increased to 2,1 million vehicles in 2014 – which amounts to a total growth of 133 % since 1990. The driving performance of LDV increased by 170 % (source: TREMOD) over the same period. The growing importance of LDV and the multitude of their applications are not reflected in the emissions modeling for LDV in Germany. The basis for the traffic emissions model TREMOD (Transport Emissions Model) as well as the Handbook Emission Factors for Road Transport (HBEFA) as input for TREMOD are, in parts, more than 20 years old. For example, the assignment of driving performance to traffic situations and road gradients is still based on an analysis by HEUSCH AND BOESEFELDT from 1996. The driving cycles which underlie the traffic situations and hence the emission factors are based on just a few data sets for LDV or are derived from passenger cars. In addition, only few measurements are available for LDV emissions, which are used for HBEFA and TREMOD. The domestic driving performance of LDV in TREMOD still mainly bases on the "driving performance investigation" (FLE) from 2002. According FLE 2002, the driving performance for LDV by residents was approximately equal to the territorial driving performance. This relationship has been carried forward since then. However, only about half of the driving performance is covered by the BASt statistics and the remainder is allocated to urban mileage and performance on municipal roads. Evaluations of FLE 2014 (which was not yet published at the time of this report) will show, whether residential and territorial driving performance are still equivalents. Preliminary results show significant deviations of the residential LDV driving performance compared to TREMOD. In addition to the sources previously used in TREMOD more data on driving performance were examined. For the year 2013, the Federal Motor Transport Authority (KBA) published for the first time the driving performance by residents according to vehicle category and vehicle age based on speedometer readings of 26,5 million motor vehicles. It is recommended to integrate the KBA statistic into future TREMOD updates. The derivation of the driving patterns which are applied to LDV in the HBEFA has up to now not differentiated between passenger cars and LDV. Comparisons between the available LDV and passenger car driving patterns in speed and time travelled show slight deviations. LDV drive with lower speed and shorter trips compared to passenger cars. However, the differences are too slight to derive stand-alone LDV driving patterns. The emission factors in HBEFA are generated from the simulation model PHEM by FVT-TU Graz. Because of the scarce data situation, the PHEM model has so far not produced LDV-specific emission maps. Instead, modified passenger car emission maps were used to generate LDV emission factors. By now additional LDV measurements for the derivation of emission maps have become available. For the LDV category, that is relevant regarding driving performance (N1-III-Diesel-Euro-5), there are currently 10 high-resolution measurements available, which could be used in the next HBEFA update. (Author/publisher)
Samenvatting