VTI on track in extended electric road project

EVolution Road is a consortium that is testing an electric road concept on stretches of road in Lund in Skåne and outside Kramfors in Ångermanland. One of several parties that are contributing with their special expertise is VTI, which, among other things, is investigating how road construction is affected through the installation of electric roads.

More knowledge about electric roads and their potential as a complement to the energy system of the future is needed. This is the purpose of the research and development project, which began as a two-year test and demonstration project in 2020 and was then extended for another two years.

This winter, VTI is assisting its partner Ramboll, which is investigating how an electric road (conductive rail), attached to the road surface, can handle tougher winter conditions in terms of durability, snow removal and friction. However, VTI's test road facilities in Linköping continue to be the site where most of the work takes place. Björn Kalman, the project's research manager, has been involved since the beginning and can tell you more.

“Previously, we investigated the type of problems that could arise when a truck repeatedly crosses a conductive road rail, for example when overtaking. That knowledge led to improvements in the design of the system. We will now investigate how the service life of road construction is affected by the installation of a conductive rail in different climatic conditions. This becomes valuable information when the concept’s profitability is to be evaluated/weighed together.”

The technology behind electric roads will make it possible to charge the vehicle while driving. In this way, the driver will avoid having to stop and recharge the batteries, which will save time. Electric roads also reduce the vehicle's battery size, which means lighter vehicles. Thus, it is possible to carry more goods or passengers, with a corresponding reduced environmental impact.

According to Björn Kalman, “it is important to do as much testing as possible before the infrastructure is put in place in order to reduce the risk of unforeseen events for such a significant investment as an electric road.”

The VTI researchers are currently concentrating on the service life of the electric road and how it is impacted by both traffic and weather changes. Björn Kalman and his colleagues will carry out so-called accelerated testing of the electric road in VTI's Heavy Vehicle Simulator, HVS. It is possible there to simulate real loads from heavy vehicles and study how different types of road constructions cope with heavy traffic.

“By exposing the road in which the conductive rail is installed to loads, it is possible to see how the road is affected via mounted sensors. With the help of this data, we can then estimate how service life is affected and where the weak points are,” says Björn Kalman.

The seasonal changes themselves can be simulated with the help of an insulated box over the HVS and an air conditioning system that can cool down or heat the electric road. The normal test temperature is usually 10 degrees, which is an average for Sweden.

“Conductive road rails are a bit special, as they are made of aluminium and thus have a different coefficient of expansion than asphalt. Aluminium expands more in heat than asphalt, which is a little more viscous,” explains Björn Kalman.

The researchers will test whether the design can withstand that stress. Therefore, in order to dampen the tension between the asphalt and the rail, there is a type of sealant based on bitumen, a binder consisting of hydrocarbons. The tests are expected to be completed sometime in March.

VTI is also involved in other aspects of the research into EVolution Road such as noise measurements, what can happen when the project is scaled up and how unevenness on the road affects the vehicle and the contact with the receiving module.

Text: Gunilla Rech

Translated by: CBG Konsult & Information AB