Cost–benefit analyses are an important analytical tool for road authorities to assess and prioritize road safety countermeasures, and commit funds that maximize road safety benefits. The aim of this study is to establish field-observed crash, injury, and cost data for run-off-road collisions with various fixed hazards and roadside infrastructure, and to derive accurate and reliable cost values for such objects for use in run-off-road cost–benefit analyses. Values are derived for passenger vehicle occupants and motorcyclists. Accurate cost data is vital to ensure cost–benefit analyses are rigorous and reliable. Data linkage between police-reported road crash, hospitalization, and personal injury insurance claim data collections is used to identify fixed-object collisions, the injuries sustained, and to establish the associated costs of treatment. A total of 5,004 passenger vehicle and 1,364 motorcycle casualties resulting from fixed-object collisions are identified, and mean injury costs per collision are established for various types of objects. The new cost values may be used in conjunction with existing cost–benefit procedures, to accurately cost fixed-object collisions and assist road authorities with decisions relating to roadside design and the commitment of funds for road safety countermeasures.