During the winter season, driving can be quite a challenging task. The streets are slippery and even the smallest mistake can lead to serious multiple-vehicle accidents. The same is true when boarding a plane. Snow build-up on the runway can compromise the traction of the landing wheels with the runway both during take-off and landing of the aircraft.Thankfully, we don't have to board our airplane and head back home during the winter months feeling uneasy about the trip since major thoroughfares, including airport runways, are constantly monitored by surface friction testers to measure how slippery the road might be and therefore ensure that the roads and runways are safe to use.Use of SensorsThe surface friction tester is used to measure the resistance between the wheel and the ground. To measure the surface friction of thoroughfares, a small compact car, loaded with many different types of sensors as well as a having a computer installed, is used. A small compact car is used for monitoring resistance rather than the use of a large truck since the smaller vehicle can provide a much more accurate reading.Use of a 'Measuring Wheel'The car used for this type of testing is equipped with a fifth wheel called a 'measuring wheel'. This measuring wheel is the primary hardware that tests the traction on the road located underneath the car. The air pressure inside the measuring wheel is set specifically to simulate the air pressure on the landing gears of airplanes to provide accurate readings.Use of Vertical PressureVertical pressure is also applied on the measuring wheel by means of a hydraulic system to ensure that it stays in contact with the road. A sensor constantly monitors the vertical pressure on the wheels so the hydraulic system can make adjustments as necessary on the vertical pressure it exerts. A torque sensor also constantly monitors the torque generated by the measuring wheel. The amount of torque generated by the measuring wheel is directly proportionate to the surface friction.Use of Rain Simulation DeviceTo simulate the effects of rain on the road, the surface friction tester vehicle is also equipped with a self-watering system. The self-watering system is a tank of water located on board the vehicle with an outlet that simulates rain in front of the measuring wheel as it turns.Use of Data by Maintenance Teams Every time the surface friction tester runs, the data that is gathered by the sensors is automatically read by the vehicles' on-board computer for final computation and evaluation. Using the surface friction tester's result, the road maintenance team is able to come up with a decision as to whether road sanding or clearing is necessary based on the surface friction test's result.Surface friction testers are an important tool on major highways as well as runways during the winter season. These sensitive machines are able to monitor any changes concerning the roads' traction to keep commuters safe while traveling. Equipped with this knowledge, even the most nervous airline passengers should be confident they will have a safe landing and be able to relax and enjoy their trip!