Utility supports represent a serious hazard that accounts for about 10 percent of all fixed-object fatal crashes. Elimination, relocation, and burying the lines are preferred options. Increased spacings or multiple use may reduce the number of poles. A breakaway device has been tested and may be considered for vulnerable locations. A breakaway device for utility pole guy wires has also been developed. As with other obstacles, shielding is also an option.
Collisions of single vehicles with trees account for nearly 25 percent of fixed-object fatal crashes and result in about 3000 deaths each year. Most of these are along county and township roads, which tend to have narrow recovery zones. Certainly, trees should not be planted in the clear zone for new construction, and mowing should discourage growth of seedlings. For existing situations, the hazard should be evaluated. Generally, a single tree with an expected mature size over 4 in (100 mm) is considered a fixed object. For small trees close together, calculate an equivalent diameter based on the combined cross-section area. Large trees should be removed where possible. Warning signs and roadway delineators can be used to indicate where extra caution is advised. Pavement markings and shoulder rumble strips can be helpful. Roadside barriers should generally be used only where the severity of striking the tree is greater than that of striking the barrier.
