Compared to conventionally powered vehicles, electric vehicles pose new issues related to safety, due to a different type of drive, In the following we outline three of these issues, which have resulted in research by the Federal Highway Research Institute (BASt).
An essential feature of electric vehicles is the possibility of energy regeneration in the battery during braking (recuperation), whereby the electric motors are used as a generator. Thereby, the occurring braking torques depend directly on the recuperation strength. BASt examines, in collaboration with FAT (German Automotive Research Association), to what extent recuperation can be implemented in certain driving manoeuvres, without the driver having to leave the stable and therefore safely controllable area of driving dynamics. Especially with a low coefficient of friction and high braking torques on the rear axle, the preservation of driving stability through controlled recuperation must be ensured.
Another project focuses on the use of various strengths of recuperation by the drivers, and on the braking torques occurring with the failure of electric motors.
Due to a growing number of electric and hybrid-electric powered vehicles in use, it is necessary to adapt the periodic technical inspection (PTI) to ensure a high level of safety of motor vehicles for years to come. In a research project, therefore, the need for change in the main inspection is investigated. The relevant components of the electric powertrain must be identified, and their failure behaviour analysed. This involves both traffic safety and environmentally critical components.
In relation to proposed changes to the inspections and inspection specifications, on the one hand, new points must be considered, such as ensuring the isolation protection of high-voltage components, while, on the other hand, certain studies (e.g. of emission values) can be omitted. For a large part of the necessary tests, the use of diagnostic data is a suitable option.
High-voltage components on a service bus's rooftop
The 47th Regulation amending road traffic regulations already takes into account the new drive concepts in many places. The development of a high-voltage directive is recommended to implement the points of investigation concerning the high-voltage system.
Some important test procedures cannot currently be technically implemented yet. Changes in the international construction and operating procedures are necessary for this purpose. These will need to be facilitated by the EU / UNECE. Moreover, there is a further need for research, in order to deal with these vehicles extensively, and to observe their further development, so that the necessary impact on the PTI can be detected in time.
Research projects on the subject of “External noise of alternatively powered vehicles" are also carried out jointly with the FAT. For blind and visually impaired people, the vehicle noise is particularly important for orientation in road traffic. It is therefore investigated to what extent electrically powered vehicles, compared to conventionally powered ones, can be auditorily detected. Various ambient noise volumes and traffic situations are considered thereby. As a result, criteria for well detectable road noises and their need are developed.