Chapter 11: Analysis of Effects Resulting from Improved Vehicle Fuel Efficiency and Fuel Price Changes Applied to the Berlin City Network

This study analyses the effect of fuel efficiency increase on travel demand in the city of Berlin. Vehicle technologies such as advanced driver assistance systems can help drivers to save fuel and thus lower exhaust emissions on a network level. In order to obtain high political endorsement among different stakeholders, the analysis of such effects which have an impact on overall fuel and emission savings are highly relevant. Recent testing of so called advanced driver assistance systems showed their ability to reduce fuel consumption and lower traffic emissions by giving driving recommendations to drivers.

Two effects on driving were simulated using a travel demand model: the increase in fuel prices which will take place in the coming years and a possible increase in vehicle fuel efficiency. Comparing these scenarios allowed us to calculate the effect of price change and the rebound effect of fuel efficiency gains using standard methods for transport elasticities. The simulation was run with the travel demand model TAPAS and the city of Berlin was the network used as a case study.

As fuel prices increase over time, driving tends to decrease. Driving increases, however, if vehicles become more fuel efficient and the result is the observed rebound effect. On a city network level, this also translates to lower emission savings than expected from the vehicle fuel efficiency gains. The rebound effect which we estimated matches similar findings in the literature, specifically in terms of their magnitude.

We used a simulation to compare scenarios of city travel demand. The result allowed us to estimate changes to the desired variables of fuel efficiency and fuel prices. For those interested in the effects of vehicle efficiency gains on city level these results are highly recommended for consideration.

The proposed framework for analysing rebound effects helped to assess the impacts of energy efficiency technologies on a city level.