According to a study conducted by the Liberty Mutual Research Center for Safety and Health, rear-end collisions account for 41% of all vehicular accidents that occur at roadway construction sites. The study, published in Accident Analysis and Prevention, analyzed 3,686 accidents at roadway construction sites nationwide. Following rear-end collisions in frequency were side-impact collisions (16%); accidents caused by small objects, such as stone, striking a vehicle (12%); crashes caused by larger objects, such as barriers, barrels or boulders (11%); and crashes involving flipped or overturned vehicles (1%). The study reports the remaining 19% of crashes could not be classified because the nonspecific nature of the accidents. The study provides suggestions for improving work-zone safety and also points to a need for research and development of more effective means of slowing drivers in work zones.