Road surface influence on rolling resistance: coastdown measurements for a car and an HGV


The influence of road surface properties, such as macrotexture and unevenness, on rolling resistance and fuel consumption is an important factor to consider when deter¬mining the coating of a road surface. Results of a VTI study show that the effect of unevenness is in general significantly smaller than that of macrotexture.

The relative smallness of this influence makes measurements of it a challenging task. In literature a wide range of results can be found and there is still much confusion and uncertainty about how large the influence actually is. In this study, an attempt is made to obtain more reliable estimates of how macrotexture and unevenness affect rolling resistance. The primary method used here is the coastdown method. It has been applied to a private car and to a heavy goods vehicle (HGV). Concerning the effect of unevenness on rolling resistance, only the coastdown method provides any information. Results show that the effect of unevenness is in general significantly smaller than that of macrotexture.

The coastdown method provides, besides information about rolling resistance, other useful data for the vehicle, such as air resistance coefficients, temperature coefficients and transmission resistance.



Millions for research into maritime transport and the environment

Maritime transport is a major source of emissions of harmful air pollutants and carbon dioxide. In a new project, a research team from the Swedish National Road and Transport Research Institute (VTI) and the University of Gothenburg has received SEK 6.4...


New research programme for more efficient travel

The Swedish National Road and Transport Research Institute (VTI) is playing an important role in a major new research programme to find radical solutions leading to fewer trips and more efficient travel, along with tools to enable better use of roads and...


Simulator used to practice emergency responses safely

Emergency responses of the police, ambulance, and rescue services are associated with a high risk of accidents, but practicing them in real traffic is neither safe nor permissible. A simulator-based method developed by the Swedish National Road and Transport...


Simulation of cut-in by manually driven vehicles in platooning scenarios

A study in a VTI-driving simulator has showed that a platoon will be able to handle a cut in from a manually driven car. The results of this study have recently been presented at two conferences in Japan.



The five-year anniversary of European Road Profile Users' Group (ERPUG) Forum will take place at Ramboll head quarter, Copenhagen, Denmark October 19-20, 2017.


Self-driving buses in Sweden next year?

A self-driving, fossil-free bus. This idea might become reality through a forthcoming collaborative project involving the Swedish National Road and Transport Research Institute (VTI), Linköping University and several other participants. The project group aim...