On April 5, 1983, a 2-ton flatbed truck, loaded with a farm plow and towing another farm plow, was traveling southbound on a two-lane, two-way rural highway near Holmesville, New York. An adult passenger bus, with 20 persons on board, was following the flatbed truck at a distance of about 100 feet. As both vehicles entered a 3,820-foot radius right curve, the towed plow suddenly separated from its hitch attachments and veered left into the opposing northbound traffic lane. A northbound tractor car-carrier semitrailer struck the plow, rupturing the tractor's left front tire. As a result, the driver lost control of the vehicle, and the vehicle veered left across the highway centerline and collided head-on with the bus. The busdriver and four bus passengers were killed. The truckdriver of the car carrier and nine bus passengers were hospitalized with various degrees of injury. Six bus passengers were treated and released.