The Runway Grooves That Help Commercial Jets Stop During Heavy Rain

Published Nov 11, 2026, 7:00 AM EST Aaron is an aviation enthusiast and world traveler with a deep interest in aerospace history and technology. He has traveled around the world numerous times, often incorporating visits to aviation museums and historic aircraft collections into his journeys. A native of New Zealand, he is an expert in aviation and maintains a broad interest in a variety of other subjects. The United States helped to pioneer runway grooving in an attempt to improve aircraft traction and water drainage. NASA's Wallops research runway carried out almost 200 braking tests with a McDonnell Douglas F-4D Phantom II fighter and a four-engine Convair 990 airliner. It was found that grooves substantially increase the braking capability of heavy jet-powered aircraft on wet, flooded, and slushy surfaces. Over the history of aviation, a variety of runway cuts were used, including square grooves, V-shaped grooves, and trapezoidal grooves. Eventually, the FAA settled on the straight-line grooves common at airports today. However, grooves are not the only way to achieve sufficient traction, with their effectiveness waxing and waning depending on the climate and other factors. Overall, it appears the worldwide trend in the 2010s and 2020s is for grooved runways to become more common, although it is difficult to quantify. FAA-Made Grooves Are Common In The US Credit: Bidragsyder l Shutterstock Some roadways, certain footpaths, and some runways have small grooves cut across them to improve traction and water drainage. These are designed to give rainwater a way out from under an aircraft's tires and to improve its traction. The key issue they are designed to solve is hydroplaning. At high enough speeds on a wet runway, an aircraft's tire footprint can lift off the pavement and ride on a layer of water. Typical FAA specifications for transverse grooves are approximately 1/4 inch (6.4 mm) in width and depth and 1.5 inches (38 mm) in spacing. A 1997 FAA Advisory Circular titled 'Measurement, Construction, and Maintenance of Skid-Resistant Airport Pavement Surfaces' noted that: "With the introduction of turbojet aircraft, braking performance on pavement surfaces has become more critical. Under certain conditions, hydroplaning or unacceptable loss of traction can occur, resulting in poor braking performance and possible loss of directional control." It adds that NASA, the FAA, the USAF, and various foreign governments conducted a series of research projects that concentrated on two main areas. One was high skid-resistant pavement, and the other was "application of proper maintenance techniques and procedures." It asserts that runway grooves are a proven and effective technique for providing skid resistance and preventing hydroplaning during wet weather. The FAA Recommended Grooving All Turbojet Airports Credit: Bjoern Wylezich l Shutterstock The 1997 FAA paper discusses the grooving techniques. These include cutting or forming grooves in existing or new pavement. Grooves in new PCC pavement need to be formed while the concrete is still plastic, while grooves in HMA pavement need to be saw-cut. It said that all runways that served or were expected to serve turbojet aircraft were considered a high priority for grooving. Existing runways without grooving also had to be modified as soon as practical. The paper noted that some existing pavements may have surfaces that are now suitable for sawing grooves. It recommended that studies should be done to determine whether they could be overlaid or rehabilitated to allow grooving. The need for grooves on runways that do not serve turbojets was not automatic and depended on circumstances. As mentioned below, this does not apply to US Navy or Air Force runways used by commercial airlines. FAA groove specifications for transverse grooves (per FAA) Width Approximately 1/4 inch (6.4 mm) Depth Approximately 1/4 inch (6.4 mm) Spacing 1.5 inches (3.8 cm) apart, center to center Today, grooving is very common around the world at major commercial airports, although it is not fully universal (even among major international airports). Grooving at general aviation airports is considerably less common. It is particularly common in commercial airports in the United States, partly due to the FAA taking a particularly strong position on the matter. Grooving Not Universal Outside Of US Credit: d13 l Shutterstock In Europe and other international airports, grooving may be less common than in the United States. ICAO's international standards are less prescriptive than the FAA's, although it recognizes grooving as a way to improve wet-runway braking. It stops short of making conventional grooving universally mandatory. Europe's EASA sees grooving as one possible method to improve runway friction and surface texture. Canada's Transportation Safety Board states that grooving reduces the potential for both dynamic and viscous hydroplaning by providing a place (such as grooves) where water can escape from underneath tires. However, it explicitly states that "runway grooving is not a requirement for new or existing runway pavement in Canada." The FAA paper above was published in 1997, but it wasn't until 2013 that Ottawa International Airport became the first airport in Canada to groove its runway. Despite being often wet, Canada is a strong example that has historically resisted mandated grooving. Instead, it has been content to leave it as an option. China is an example of a country that prefers alternative treatments such as stone mastic asphalt and other textured pavement surfaces. France also uses specialized asphalt surfacing as an alternative. A 2010 Canadian safety investigation found that grooving is present at almost all major airports in the US, UK, continental Europe, Australia, and Japan. Less Common At General Aviation Airports Credit: Aaron Spray Most small general aviation airports do not have grooved runways, and this is driven by several practical reasons. One is that light aircraft have a lower landing weight and speed than commercial airlines and so are less susceptible to hydroplaning. Another is that low traffic volume may not justify the costs of grooving. Engineers often assess that these airports are built with pavement characteristics that already provide adequate friction and drainage without the need for grooves. Some airports achieve adequate wet-weather friction through alternative surface treatments. These include porous friction course. Here, a porous asphalt overlay allows water drainage, concrete texturing, surface aggregate selection, and runway gradients. With concrete texturing, concrete can be finished with wire combing or tining, creating a textured surface. General aviation aircraft are actually quite vulnerable to runway skidding and hydroplaning, but grooving is not necessarily seen as the way to address this. Much of the issue stems from light aircraft often lacking anti-skid braking systems, operating from shorter and less frequently maintained runways, and their relatively small tires. Without anti-skid braking, if a pilot applies too much braking on a slippery surface, the wheels can lock and skid. After a wheel locks, its braking effectiveness tends to deteriorate. Making matters worse, locked wheels make directional control more difficult and make the aircraft vulnerable to crosswinds. A Few Factors Against Grooving Credit: Serhii Milekhin l Shutterstock One of the main disadvantages of grooves is maintenance. Rubber from the aircraft tires accumulates in the grooves, especially at the touchdown zones. This can reduce their effectiveness over time. Consequently, grooves can add yet more maintenance for the airport. There are some other disadvantages of grooving beyond construction costs and maintenance, although they are typically manageable. For instance, it can damage the pavement, add foreign object debris by accumulating rubber, slightly increase tire noise, and other minor considerations. One of the biggest cases against them is when the climate is dry. Wet airports like those in the US Pacific Northwest and Northern Europe can benefit from grooving. However, this does not transfer to dry airports, such as those in Saudi Arabia, Egypt, or Arizona. With that being said, these areas can experience flash flooding, making grooving momentarily useful. At the same time, desert and sandy environments can increase the contamination problem, with grooves accumulating sand. A residual benefit is that in colder climates where there is ice and snow, grooves can retain anti-icing and de-icing chemicals. They can help drain melted snow and ice. Lack Of Grooves May Have Worsened Some Overruns Credit: Resul Muslu l Shutterstock Modern airliners can lose traction on wet surfaces, but in cases where accidents have happened, hydroplaning is often seen as one contributing factor. Modern jets come with anti-skid braking, ground spoilers, thrust reversers, and autobrakes. Since 2000, one of the most notable incidents came in 2019, when a Boeing 737 operating as Miami Air International flight 293 overran the wet and ungrooved runway at Jacksonville. The aircraft overran the runway into the St. Johns River, although there were no serious injuries. This accident happened at a US Navy airfield, not Jacksonville International Airport, and so was not covered under the 1997 FAA regulations. The NTSB report states that: "The NTSB determined that the probable cause of the 2019 runway overrun of the Boeing 737 in Jacksonville, Florida, was, in part, 'an extreme loss of braking friction due to heavy rain and the water depth on the ungrooved runway, which resulted in viscous hydroplaning.'" Another hydroplaning incident involved United Express in Ottawa in 2010, when an Embraer aircraft overran the wet and ungrooved runway. As previously noted, Ottawa became Canada's first airport with a grooved runway in 2013. Other notable incidents on this front included American Airlines flight 331 at Kingston (2009) and Southwest Airlines flight 1919 in Chicago (2011). Elsewhere, Virgin Australia suffered a similar occurrence on New Zealand's then-ungrooved Christchurch runway in 2015. The Australian Transport Safety Bureau found that Virgin Australia's company policy at the time treated damp runways as dry, leading to a miscalculation of landing performance requirements and high crew workload during a revised approach.