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Photo of GripTester


Skid Resistance (Surface Friction) Tester

This surface friction (skid resistance) tester has been supplied to highway and airport authorities since 1987. The GripTester surface friction tester was developed in collaboration with Cranfield University and international acceptance was achieved with the help of the UK TRL, PIARC, the US FAA and NASA.

This highly innovative product has excellent correlation with long established friction testers, which has led to world-wide acceptance and to recognition by international organisations such as ICAO and PIARC.

Specified by ICAO and covered by BS7941-2:2000, the GripTester is the most widely used runway surface friction tester in the World. With over 450 units currently in operation worldwide, the GripTester provides users with the flexibility to undertake the level of runway surveys, which is most appropriate for the volume of air traffic handled

The award criteria for this contract were published as economically most advantageous tender in terms of :
  • Weathering, long term use and the deposition of rubber on roads and runways can all result in slippery surface conditions. The GripTester® can quickly and conveniently provide road and airport authorities with reliable data on which to plan corrective maintenance.
  • In winter conditions, airport operators use the GripTester to provide friction data for their own staff and for airlines.
  • Operational testing in natural conditions is also carried out by road authorities investigating accident sites.

Price, running costs, profitability, quality, technical merit and lifecycle costs

The GripTester is reliable, versatile and easy to use. Operating and maintenance costs are low and the quality of the computer generated printed output is extremely high.

The GripTester thus helps users reduce maintenance costs and improve transport safety on roads and airports by:

  • Identifying areas of poor surface friction before hazardous conditions occur
  • Obtaining information vital to the determination of maintenance priorities
  • Assessing the friction characteristics of winter runways
  • Surveying road accident sites to ascertain whether surface conditions are likely to have been a contributing factor

We would now like to summarise some of the key features and benefits of the GripTester:  


  • Rugged, compact and lightweight; easy to operate and to transport
  • Braked wheel, fixed slip design with drag and load measured continuously
  • Can be towed at any of the standard testing speeds up to 130 km/h; can also be used in pushing mode
  • Simple on-site calibration takes only 10 minutes
  • Rapid and simple data acquisition and presentation

  • Helps highway and airport authorities schedule maintenance activities
  • Helps improve transport safety
  • Allows highway authorities to link into the PIARC International Friction Index
  • Allows airport authorities to comply with ICAO regulations
  • Gives US airports access to FAA funding

Photo of Grip Tester being used in front of Concorde

The GripTester is a braked wheel, fixed slip device with drag and load (horizontal and vertical force) continuously monitored and their quotient (coefficient of friction) calculated and displayed. The data collection computer can be any standard IBM compatible laptop or it can be a specially designed, ruggedised computer.

Photo of Computer

Calibration is from first principles and can be carried out by the operator, on-site, in about ten minutes. The measuring tyres, made of ASTM rubber, are all tested for consistency before delivery.

Main Application Areas

The GripTester is used extensively in two main application areas and these are now described.


Photo of truck on road with Griptester

The GripTester is a highly manoeuvrable instrument for investigating accident sites and other problem areas. It can also carry out substantial surveys as part of a Pavement Management System. The transformation from one role to another is effected simply by changing the towing vehicle. In both roles, the GripTester's low consumption of water is a great advantage.

The data collection software provides the operator with facilities for recording markers during surveys. Results can be scanned in the field and the data presentation software can later be used to produce a printed report. The data files may also be imported to any standard spreadsheet.

Photo of two data pages

Excellent correlation with SCRIM has been established at the UK TRL and the GripTester successfully took part in the in 1992 PIARC "International Experiment to Compare and Harmonise Texture and Skid Resistance Measurements".

Results can therefore be linked both to the thresholds used by the UK DTp and to the PIARC International Friction Index.


Photo of Airport

The GripTester can be towed by almost any vehicle and a complete runway survey can easily be carried out by a single operator. The average friction reading for each third of the runway is automatically displayed during the survey and results can be inspected while still on the runway.

Data can be printed (on standard size paper) and/or archived to a PC for detailed analysis and comparison. This is particularly useful when monitoring the effects of rubber deposits and the efficiency of rubber removal programmes.

Photo of computer screen

Where winter operational testing is a necessity, a dedicated GripTester is required: this can be operated on runways contaminated by snow, slush or standing water at least up to the levels specified by the FAA in their Advisory Circulars.

Where only maintenance testing is required, the GripTester (and its self-watering kit) can easily be transported by light aircraft for shared operation, allowing ICAO recommendations on runway friction testing to be more widely satisfied.

This versatile instrument, which is included in the ICAO Airport Services Manual and Annex 14 to the Convention on International Civil Aviation, is already in use at some of the world's busiest airports as well as at some of those with only occasional traffic.

For instance, GripTesters can be found in Hong Kong, throughout the Caribbean Islands, extensively throughout the UK and mainland Europe, Estonia, Canada, South Africa, Malaysia, New Zealand, Poland, Norway and ...............

In addition the GripTester is used by the US and Canadian Air Forces and the US Navy.

Additional benefits to highway and airport maintenance staff can be achieved with the ICELERT weather monitoring system to help keep the runway and taxi-ways free of ice by monitoring surface conditions and performing anti-icing operations BEFORE ice formation.

Other Applications

The GRIPTESTER can also be used in a wide range of other important application areas such as :

Pedestrian Areas

Photo of GripTester being     pushed

To allow highway authorities to record the surface friction of pedestrian areas, the GripTester can be used in pushing mode with its own self watering tanks. This improves scheduling of maintenance work and can contribute to an authority's defence against litigation arising from pedestrian accidents.

Horizontal Road Markings

Slippery horizontal road markings can be a hazard for road users and assessing their friction characteristics can be difficult. British and German authorities have pioneered the use of the GripTester in towing mode for on-site testing of motorway markings; in France it is extensively used in pushing mode for testing homologation sites and urban areas.


Photo of Oil Platform

The GripTester can easily be transported to measure the friction of helidecks on offshore oil platforms. This can eliminate the need for the large, inconvenient rope mesh nets. The GripTester has been used extensively on offshore North Sea oil platforms over the past few years.

It has also been used by both the UK and the US naval authorities to measure the surface friction on the flight decks of aircraft carriers and naval helidecks.

Research into Surface Characteristics and Materials

With its capacity for accurate acquisition of surface friction data under widely differing environmental conditions and at speeds ranging from 5 km/h to 130 km/h, the GripTester is an ideal research instrument for Materials and Transport Safety engineers.

Analysis and Presentation Software

A comprehensive suite of analysis and presentation software is available to support the GripTester :

Photo of Computer Output

GTMonitor for comparing "there and back" runway monitoring surveys

GTCalibrate for producing a colour map from a full "side to side" runway calibration survey

GTUser for reviewing a road survey and printing a detailed report.


A wide range of accessories are available, including:

For self-watering: a variety of tanks, pumps and control valves

For operation in pushing mode: pushbar and water tanks

For the data collection computer: carrying cases and in-vehicle supports.

Technical Specifications and Technical Reports

Later this year we will be including additional pages with key technical reports along with details of the main specifications.
For example we can provide :

A comparison report written by the UK TRL (Transport Research Laboratory - "A comparison of SCRIM and GripTester 1993".

"Friction Harmonics" by Delia Harverson and published in World Highways, March 1993

along with other key articles and reports.

If you require these now please ask.