Loose Chippings

Loose chippings are loose gravel or stone fragments which have become detached from a road surface and form a hazard to vehicles using that road.

They may be the result of a poorly constructed chip seal, when unbound surplus aggregate is not removed from the surface. Another cause is raveling of a chip seal or asphalt concrete pavement. This is usually the result of a poor bond between the asphalt and the aggregate. As a result, the aggregate breaks free from the road surface. Raveling may also be caused by mechanical wear from snowplows or studded snow tires.

Gravel may also be deposited on the road by erosion of cut sections above the road. It can also be carried onto the road by tyres of a vehicle that was driven onto a gravel shoulder, or entered a paved road from a gravel road.

Excessive speed while driving through loose chippings can result in damage to both the road and vehicles. Loose chippings can reduce traction and cause loss of control. This presents a special hazard to motorcyclists and bicyclists, who may lose their balance and fall if their tires start sliding. The loose chippings are picked up by tyres and may be spun off to become high speed missiles, potentially injuring or damaging other persons or vehicles on road.

Loose chippings may also accumulate on verges where they may choke drainage channels.

In many countries, road signs are put up, requiring vehicles to drive at a low speed. In the UK, these temporary traffic signs will require the driver to proceed at 20 mph.