Sometimes the debris on a roadway will cause or contribute to an accident or injury.
The most common ways that road debris may contribute to accidents is by either:
By causing a driver to lose control of his vehicle; or
By being launched by the tires of a car into the windshield of another vehicle.
If an item in the roadway are particularly large, it may also necessitate sudden braking by an approaching driver or require drivers to change lanes, increasing the risk of a collision.
Most drivers have personal experience with having a stone or object strike their windshield -- an event that can be very surprising and distracting. In some cases the object will go through the car window, and even strike the driver or another occupant.
Some roadways are susceptible to falling rock or to mudslides. If you are driving in an area that appears potentially susceptible to fallen rock or mud on the road, or where signs indicate that you should watch for rocks or mud on the surface of the road, you should modify your driving conduct accordingly.
The government agency that is responsible for road maintenance will normally respond to the presence of road debris, both by periodically cleaning debris from the shoulder of the road and by responding to remove large items or debris from traffic lanes. In most cases where an accident results from road debris, it is difficult to prove that the government should be liable for injuries arising from the presence of debris on the road. In order for a government agency to be liable, you must typically establish both that the government had knowledge of the presence of the object or debris, and that they failed to respond to its presence within a reasonable amount of time after learning of its presence. Principles of governmental immunity may provide the government agency an additional defense against liability claims.
Even when an object appears to have been placed in the road or to have fallen off of another vehicle, it is often difficult to identify the driver or person who is responsible for the presence of the debris or object on a road. Even a minute after a truck loses a piece of retread, a muffler falls off of a car, or an item of furniture falls off of somebody's pickup truck, it can become nearly impossible to establish how the debris came to be on the road. As a result it is often difficult to recover damages for injuries from the responsible party following an accident caused by road debris.
Sometimes there will be witnesses to the events leading up to an accident. For example, sometimes a witness will see debris fall off of the back of a truck or other vehicle. If the witness can identify the vehicle, its owner or driver, it may be possible to pursue a negligence claim against the driver for harm or injuries caused by the debris.