Lifespans of passenger cars in Europe: empirical modelling of fleet turnover dynamics

Abstract

Cars have a high share of global transport-related CO2 emissions. To model the market diffusion of new energy carriers and powertrains like electric vehicles, fleet turnover models are commonly used. A decisive influence factor for the substitution dynamics of such transformations is the survival rate of the national car fleet of a country. It represents the likelihood of a car reaching a certain lifespan. Due to a lack of data, current methods to estimate such survival probabilities neglect the imports and exports of used cars. Existing studies are limited to countries with a predominant market of new cars, compared to low numbers of imported and exported used cars. In this study, we resolve this marked simplification and propose a new method to estimate survival probabilities for countries with a high number of imported and exported used cars. Empirical data on the car stock, on inflows of new and used cars, and on outflows of exported and scrapped cars are gathered from 71 national statistics offices. Survival rates of the car fleets of 31 European countries are derived, for which we find a pronounced regional variability. Average lifespans of cars vary from 8.0 to 35.1 years, with a mean of 18.1 years in Western and 28.4 years in Eastern European countries, revealing the high impact of cross-border flows of cars. The study also shows that survival rate estimates can be improved significantly even in the absence of reliable data if a combination of a Weibull and a Gaussian distribution is used. It is likely that the predictive power of existing models (regarding the future environmental impact of car fleets) could be improved significantly if these findings were considered accordingly. The findings of this study can directly be included in fleet turnover and policy assessment models. They also enable the analysis of economic and environmental spillover effects from the imports and exports of used cars between countries.

Carbon Reduction of the Three-Year Air Pollution Control Plan under the LEAP Model Using a GREAT Tool in Panzhihua, China

“…From the Panzhihua Yearbook Statistics 2020 [ 24 ], it is known that the total stock of buses and trucks in the market in 2019 was 41.417 thousand units, and according to the motor vehicle market turnover in the ten years from 2010 to 2019, an average of 2.4 thousand buses and trucks were traded each year. In the Panzhihua LEAP transport module, the academic life of the vehicle is set at 22 years, a vehicle survival curve is added [ 31 ], and the free market for vehicles is interfered with by the policy requirements of the three-year plan. As shown in Figure 10 , the market share of ICE and NEA vehicles for trucks and buses and the share of the stock of vehicles using different energy sources change under the traffic optimization scenario in the Panzhihua LEAP transport module.…”

Improving Transport Modeling in MESSAGE Energy Planning Model: Vehicle Age Distributions

“…Furthermore, our approach allows the representation of vehicle age distributions of different shapes. Countries such as the Czech Republic, Poland or Lithuania have a nondeclining vehicle age distribution [30], i.e., these countries have high used vehicle imports from foreign markets. Such vehicle age distributions cannot be correctly represented by applying the survival rates as they are limited to the declining curve.…”

Prospective life-cycle assessment of greenhouse gas emissions of electricity-based mobility options

“…To this end, a fleet evolution scenario is established, in which each EBM powertrain is individually introduced such that Switzerland's current and foreseeable future targets for average CO 2 emissions of newly registered passenger cars are fulfilled. The fleet then evolves following a simplified stock-flow cohort model in which all vehicles are scrapped or exported, when they reach the age of 15 years [43].…”