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Surface Friction

Fugro offers friction testing services for pavement management, accident sites, maintenance and forensic investigations. Friction testing helps agencies determine if a pavement requires resurfacing or other processes to provide adequate skid resistance. Fugro has extensive experience in network and project level testing for various states. Our system meets the ASTM E274 standard procedure for measuring the skid resistance of paved surfaces with a full-scale specialized test tire. The Friction Tester is calibrated yearly at the Texas Transportation Institute (TTI) calibration facility to ensure accuracy and comparability with other equivalent testing systems.

This method uses a truck with a water tank and instrumentation to pull a trailer that distributes water in front of the trailer tire and locks it to simulate wet conditions. Measurements are recorded with a steady-state friction force on a locked test wheel and transported over a wet pavement surface. This is conducted under constant load and constant speed. The values measured record frictional properties for skid resistance evaluations of pavements.

Skid resistance is an important pavement evaluation parameter because:

  • Inadequate skid resistance will lead to higher incidences of skid related accidents
  • Most agencies have an obligation to provide users with a roadway that is "reasonably" safe
  • Skid resistance measurements can be used to evaluate various types of materials and construction practices

Skid resistance changes over time. Typically it increases in the first two years following construction as the roadway surface is worn away by traffic and rough aggregate surfaces become exposed, then decreases over the remaining pavement life as aggregates become more polished. Many factors affect skid resistance including but not limited to seasons, flushing, polished aggregate, raveling and crack sealant.

Download the Surface Friction brochure