The impacts of automated passenger vehicle driving were studied in a flagship EU project. The results were based on simulations using data collected from real automated vehicles in real-world traffic on motorways, in urban and rural environments, and on test tracks. It was assumed that automated driving would be available on urban streets and motorways under good driving conditions, although not yet in all locations or under all conditions.
“To our knowledge, this is the most comprehensive impact assessment carried out to date on the future use of automated vehicles in European traffic. For VTT, working with European original equipment manufacturers (OEMs) and other stakeholders in the development of automated driving was a great opportunity to be part of the future of transport,” says Satu Innamaa, Senior Scientist at VTT.
According to the results, 20% of fatal highway accidents today could be avoided if 30% of passenger vehicles in the traffic flow were automated. In urban environments, the corresponding reduction in accidents would be 22%. The number of accidents resulting in serious and minor injuries would decrease even further. A minor negative impact would be a 0–4% increase in travel times due to changes in target speeds and new routes, although technical solutions were found to mitigate this increase.
“Overall, the benefits of automated driving are expected to far outweigh the social costs and potential negative consequences. From a socioeconomic perspective, the impact on safety and increased travel comfort constitute the main monetary benefits, while the increased travel time represents an economic disadvantage,” says Satu Innamaa.
Automated driving will likely improve the quality of journeys and have a significant impact on mobility. By allowing users to perform non-driving activities, the improved journey quality may lead to more frequent and longer trips.
Multiple Impacts on the Transport System:
The project addressed EU-level impacts encompassing the entire traffic flow, including both automated and non-automated light and heavy vehicles, across all driving scenarios. The traffic efficiency and environmental results revealed that, with automated vehicles in the traffic flow, the average traction energy consumption per kilometer traveled decreases under most conditions. Impacts on CO2 emissions at the network level were small (between -1% and 0%).
“Although automated vehicles tend to be electric, the project was independent of the type of engine. It was important to limit the scope of the research strictly to the impact of changes in driving behavior caused by automation, and not to mix it with the impact of fleet electrification,” Innamaa explains regarding the impact on CO2 emissions .
In addition to the reduction in current accidents due to the introduction of automated driving, new types of accidents could emerge. The study estimated that these would represent 0.3% of accidents on highways with a 30% adoption rate, resulting from situations where the automated vehicle cannot continue driving and needs to reduce speed or even stop before the human driver takes over. Therefore, this proportion of new accidents is considered very small compared to the reduction in current accidents that automated driving will bring.
Key impacts of automated driving (assuming 30% adoption of passenger vehicles):
20% reduction in fatal accidents on highways and 22% in urban traffic;
0–4% increase in average journey time for all vehicles;
decreased traction energy consumption per kilometer traveled;
slight reduction in CO2 emissions;
and greater journey comfort.
flagship EU project
, the €60 million project was coordinated by Volkswagen AG, with the participation of most major European automakers and other relevant stakeholders. VTT was responsible for multiple work packages, including the project methodology and impact assessment. The four-year project concluded in November 2025.
“It was inspiring to work with a consortium, testing real automated vehicles being developed for the market, and exploring the various impacts of automated driving on the transportation system. The project was extremely interesting but also very challenging. We had to consider multiple aspects when developing the methodology and then integrate all the pieces to carry out the assessment. Leading a multinational team across different organizations added an extra dimension,” says Satu Innamaa.
Key facts about the Hi-Drive project:
Duration: 53 months, from 1 July 2021
Total budget: 60 million euros, EC funding: 30 million
Coordinator: Volkswagen AG
Participation: 53 organizations
