Data on bridge movements and their effects were collected from 314 highway bridges in 39 states, the District of Columbia, and 4 Canadian provinces. These data have been analyzed to compare the movements that occurred with evidence of structural damage and to gain some insight into the basic causes of the movements and the resulting damages. The tolerance of the bridges to the various types and magnitudes of movements was also evaluated. It was found that, in general, bridge structures have much greater tolerance to differential vertical movements than is generally thought. However, in many instances, it was found that the design and/or construction practices used led to bridges in which structural damage, particularly to joints and bearings, was produced by relatively small horizontal movements of abutments and piers and the level of these damages was more severe when the horizontal movement was accompanied by vertical movement. In many instances, it was possible to identify the cause or causes of the bridge movements and the resulting structural damage. These causes suggested possible changes in design and construction practice that could help to reduce the probability of damaging movements. It is concluded that, although many highway bridge structures can tolerate significant vertical and horizontal movements, depending on span length and stiffness, there are relatively simple design and construction techniques available that can greatly reduce the possibility of movements and thus reduce the potential for structural damage and the resulting maintenance.(Author)