Pavement and pavement marking wear by studded tires are suspected causes of several effects that result in decreased highway safety. In order of decreasing hazard the most important effects are 1. Tire Hydroplaning and Wet Skid 2. Road Repair and Maintenance Hazard Other effects, discussed in more detail in the report, are felt to be of less potential hazard than the factors cited above. In the case of hydroplaning studded tire wear was found to be both beneficial and detrimental to safety. In some cases, a coarsening of the surface produces enhanced skid resistance properties. In other cases, studded tire wear has a smoothing effect and the skid number is reduced. If road maintenance activity projections resulting from studded tire wear hold true, the construction sites may serve to be a significant source of accidents. Of course, the decision to repave or recondition a road surface is at least partially determined by the known or suspected relationship between road damage and accidents. Thus extensive repairs partially assume a knowledge of the known accident causation factors of damaged pavement. Some possible studded tire effects such as the ejection of studs from high speed vehicles, or the degradation of vehicle corn ponents were judged to have little relationship to accidents.