Christine Weiss

Hybrid Modeling Approach of Car Uses in Germany on Basis of Empirical Data with Different Granularities

The use of private cars in Germany has not yet been analyzed from a longitudinal perspective: most travel surveys consider only a single day. Daily car usage is not identical over a given period because car owners use their vehicles for daily routines (e.g., commuting) as well as for infrequent events, such as holiday trips. Another problem of short-period surveys is that they underestimate the share of cars used for long-distance travel. The current work may help to improve the reliability and realism of statements about the extent to which German cars could be replaced by electric vehicles. The authors developed a hybrid modeling approach that aims to obtain car mileage per day for a full year. This approach is based on empirical data with different granularities. Input data are derived from the annually conducted German Mobility Panel, including a survey of fuel consumption and odometer readings, and the long-distance travel survey INVERMO. The study showed that 13.1% of the modeled German private car fleet never exceeded 100 km/day during a full year. Furthermore, cars were driven more than 100 km on 13.3 days/year on average. Mainly used cars (first cars) of a household were used for longer distances rather than second cars. A comparison of average mobility figures from the model approach with the Mobility in Germany national travel survey showed the model results as reliable and realistic.

Changes in Variability and Flexibility of Individual Travel in Germany: Trends and Drivers

Are daily life and daily travel behavior in Germany more flexible today than it was 10 to 15 years ago? Against the background of an increasing use of information and communication technologies (ICT) and the question of that impact on daily life, this paper analyzes changes in the variability of travel behavior. The paper examines the data from individual travel diaries of a whole week covering a longitudinal perspective over 15 years. These two dimensions of information allow for more detailed evaluation of variability profiles. The analyses were based on traditional key values of daily travel as well as new customized measures of individual variability in travel behavior in the course of a whole week. The paper investigated the temporal development by sociodemographic group. The results show that travel behavior patterns of young men and woman in Germany are becoming more similar. The young age group drives several trends, including multimodality. However, at the same time, young men are shifting their leisure habits toward more home-located activities; this effect is possibly partly induced by the influence of ICT.

Modelling the Weekly Electricity Demand Caused by Electric Cars

Abstract As transport is one of the big sources of carbon dioxide emissions, it is natural to seek for solutions reducing the carbon dioxide emissions in transport as well. Replacing cars powered by a combustion engine by battery electric vehicles may be one measure to achieve this goal, at least as long as the electricity consumed by these cars is produced carbon neutral or in a low-carbon manner. In Germany, the Federal Government aims at a stock of one million electric vehicles in the year 2020. This goal is very ambitious, since customers are reluctant to buy battery electric cars, probably most of all due to their limited range. A possible solution to the limited range problem is the use of Plug-in Hybrid Electric Vehicles or Extended Range Electric Vehicles (EREV), combining an electric battery with a combustion engine or a generator. These solutions overcome the range limitations while at the same time allowing driving on electric power for the majority of the total mileage. In this paper, we analyse the effects of an increased use of EREVs and battery electric vehicles using the travel demand model mobiTopp. For three scenarios with different rates of market penetration of electric vehicles, the travel demand and car usage is simulated over a simulation period of one week. The results show, that for 65 up to 70 percent of the mileage, EREVs can be driven in battery-only mode, demonstrating the usefulness of the EREV concept and indicating a substantial potential for the reduction of carbon dioxide emissions. The results, however, also show that with an uncontrolled charging strategy, i. e. every car recharges immediately after accessing a charging location, the peaks of electricity demand for charging the electric cars occurs when the general electricity demand is already high. During these periods, additional electricity demand is typically covered by gas-fuelled power plants, thus using fossil fuels. Therefore, the concept of introducing electric vehicles in order to reduce total carbon dioxide emissions can only succeed if combined with intelligent charging strategies.

Who Uses Freeways and Who Pays for Them? Model-Based Analysis of Distribution Effects of Toll Tariff Systems in Germany

The introduction of a car toll on German freeways is a current political discussion and raises several questions, including whether particular car owner groups are financially disadvantaged by certain toll tariff systems. Analyses of this issue require a detailed knowledge of the frequency and intensity of freeway usage across the car fleet from a longitudinal perspective. Because such data were not available for Germany, this study developed an approach that extended a microscopic data set of car trips for a 1-year period by modeling the highway usage of those trips. The resulting annual toll expenses for every car in the sample were evaluated for three toll tariff systems: an annual fee, combinations of tariffs for different periods, and a tariff that depended on the vehicle miles traveled (VMT). The analyses illustrated that the toll expenses per car varied greatly between the systems. Car owners with low annual mileages were financially disadvantaged by the annual sticker toll tariff. Comparisons of toll expenses and the socioeconomic aspects of car owners and car characteristics showed similar results. Car owners with a low income and retired or unemployed persons would benefit notably from the VMT toll.

Why the car is key to low carbon mobility in Brazil

The challenge of transitioning to low carbon mobility differs between industrialized countries and emerging economies. Industrialized countries – where mobility is high but its growth has slowed down – must reduce absolute levels of transport emissions, i.e. they have to transition from high carbon to low carbon mobility. Emerging economies – where continued growth of both transport and associated emissions appear inevitable – have to find mobility pathways that allow for growth of transport while curbing the growth of transport emissions. Different strategies are adequate to achieve this objective in an emerging economy depending on respective framework conditions. Brazil is a particularly interesting case. As this chapter will illustrate, Brazil is headed toward an auto-dominated mobility system. We argue that Brazil must achieve low carbon automobility in order to achieve low carbon mobility.