Road debris, a form of road hazard, is debris on or off a road. Road debris includes substances, materials, and objects that are foreign to the normal roadway environment. Debris may be produced by vehicular or non-vehicular sources, but in all cases it is considered litter, a form of solid waste. Debris may tend to collect in areas where vehicles do not drive, such as on the edges (shoulder), around traffic islands, and junctions.
Road spray or tire kickup is road debris (usually liquid water) that has been kicked up, pushed out, or sprayed out from a tire. In 2004, a AAA Foundation for Traffic Safety study revealed that vehicle-related road debris caused 25,000 accidents and nearly 100 deaths a year.
Road debris can be caused by various factors, including objects falling off vehicles or natural disasters and weather, specifically wind, storms, tornadoes, hurricanes, etc.
Examples of road debris include:
Particulates, dust, dirt, sand, and mud
Asphalt, concrete, pebbles, rocks/stones/boulders, etc.
Particles of road salt and other de-icers
Litter, food waste, animal feces/manure, furniture, electrical appliances, mattresses, and other items of garbage, trash, rubbish and refuse
Broken glass, nails, screws, and other often sharp objects
Car parts, tire tread, etc.
Bicycles, roof racks, luggage, lumber, construction materials, pallets, crates, and other solid objects accidentally or deliberately dropped from moving vehicles
Animal corpses (roadkill)
Broken glass, plastics, and other solid materials that fall off vehicles during traffic collisions
Ice, snow, rain water (puddles or flooding), and other liquids such as grease and engine oil
Plants and their parts: branches, leaves, sticks, twigs, seeds, or grass clippings.
Road slipperiness
Road debris is a hazard that can cause loss of vehicle control with damages ranging from a flat tire, vehicular rollover, penetration of the passenger compartment by the debris, or collision, with accompanying injuries or deaths.