Norsemeter ROAR Friction Tester

The Roar unit is especially designed for the measurement of pavement surface characteristics on roads. Relevant services are for example routine survey of highways for identification of poor friction sections.

The technology is based on a very simple idea: In order to stop or steer a car or an aeroplane, you need to use the friction force between the tire and the surface. The more friction, the better you steer and the faster you stop.

Norsemeter ROAR MK-II is a trailer equipped with the ROAR friction measuring unit, which has a special high precision hydraulic brake machine with a standard ASTM 1551 test tyre (diameter 40 cm / 16in). The equipment can be operated in all travel speeds with measurement able to take place above 30 km/h.

Overview of Skid Resistance

Skid resistance is the force / friction developed when a tyre that is prevented from rotating slides along the pavement surface. It is at its lowest when affected by water, mud or loose detritus resulting from the day to day usage of the road network. Skid resistance measurement is an important safety factor – inadequate skid resistance will lead to higher incidences of skid related accidents.
The factors that can influence the level of surface friction include:

  • Vehicle speed and surface texture
  • Water depth and tyre characteristics
  • Seasonal, year-on-year and regional variations
  • Temperature
  • Road geometry
  • Surface contamination
  • Surfacing aggregates
  • Surfacing type and age (early life skid resistance)