SFT Friction Testers

Locked wheel friction testers

For more than 40 years, locked wheel friction testing has been the most accepted method for measuring road pavement friction in USA, Canada, and many countries worldwide. ICC Surface Friction Testers (SFT) provide a safe, efficient, and reliable means of measuring surface friction on existing and new surfaces for roadways, bridges, crosswalks and patterned pavements.

Designed and fabricated in our Florida facility, the ICC Friction Tester consists of a custom fabricated trailer and tow vehicle that offers single- or dual-sided testing and is available in standard range and extended range models.

Friction is key to road safety

FHWA analysis shows that over 50% of fatal crashes are due to roadway departure. Pavements with insufficient friction when wet and roads with horizontal curves are the leading road-related factors.

Managing pavement friction on roads is critical for safety. Advances in materials have made it possible to repair road sections with poor friction by applying high friction surface treatments (HFST). To keep road users safer and to achieve “zero deaths” safety goals, most transportation agencies need a way to identify current and potential safety problems proactively. This also helps avoid costly legal claims.

Working Principle

Locked wheel friction testers measure pavement friction accurately and directly.  The friction coefficient is calculated between a tire on the specialized trailer as it skids over wet pavement. The trailer carries the water application nozzles, special braking system, and the control system. The truck carries the water tank, water pump, pneumatics, and operating computer.  The system:

  • Measures the average friction coefficient in accordance with ASTM E274
  • Identifies changes in surface friction due to deterioration, weathering, or other characteristics
  • Collects optional macrotexture data to help identify the “coarseness” of the pavement surface, known to influence friction

The collected data is used to:

  • Test characteristics of applied surface treatments, such as HFST
  • Determine safe friction levels on roadways, intersections, and crosswalks
  • Identify resurfacing or rehabilitation needs for current paved surfaces


The trailer is available in single- and dual-sided versions:

  • Single-sided trailer – Applies the water and braking force on one side only
  • Dual-sided trailer- Alternates between the two sides to measure friction in both wheelpaths


The unique benefits of ICC SFT friction testers include:

  • Maintenance-free, coil-over shocks instead of air-adjustable shocks
  • Check valves installed before the electric valve to save water, which translates to fewer refill stops
  • Proprietary racing-style aluminum brake calipers
  • Proximity switch for DMI, which enables a field fix versus down time in the garage
  • Aluminum fenders and hoods with Kevlar coating
  • Top-down access to trailer suspension system
  • Rapid fire mode option for closer spacing between tests; faster lockup reduces water usage
  • User friendly and time efficient
  • Innovative development since 1975
  • Adheres to ASTM and AASHTO industry standards

Industry Standards

  • ASTM E274 Skid Resistance of Paved Surfaces Using a Full-Scale Tire
  • ASTM E501 Standard Rib Tire for Pavement Skid-Resistance Tests
  • ASTM E524 Standard Smooth Tire for Pavement Skid-Resistance Tests
  • ASTM E556 Calibrating a Wheel Force or Torque Transducer Using a Calibration Platform
  • ASTM E1337 Standard Test Method for Determining Longitudinal Peak Braking Coefficient
  • ASTM E1845 Standard Practice for Calculation Pavement Macrotexture Mean Profile Depth
  • AASHTO T 242 Standard Method of Test for Frictional Properties of Paved Surfaces
  • AASHTO M 261 (Standard Specification for Rib-Tread Standard Tire)
  • AASHTO M 286 (Standard Specification for Smooth-Tread Standard Tire)

The SFT is available in two models for project- and network-level testing.


The Standard Range safety friction tester capable of holding 350 gallons (1,300 L) of water.


Our extended range safety friction tester capable of holding 1,200 gallons (4,500 L) of water.

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