On Friday, January 30, 2009, about 4:06 p.m. mountain standard time, a 2007 Chevrolet/Starcraft 29-passenger medium-size bus, operated by DW Tour and Charter and occupied by the driver and 16 passengers, was traveling northbound in the right lane of U.S. Highway 93, a four-lane divided highway, near Dolan Springs, Arizona. The bus was on a return trip from Grand Canyon West to Las Vegas, Nevada, after a day-long tour. As the bus approached milepost 28 at an estimated speed of 70 mph, it moved to the left and out of its lane of travel. The driver steered sharply back to the right, crossing both northbound lanes and entering the right shoulder. The driver subsequently overcorrected to the left, causing the bus to yaw and cross both northbound lanes. The bus then entered the depressed earthen median and overturned 1.25 times before coming to rest on its right side across both southbound lanes. Major safety issues identified in this investigation were the failure of the bus driver to attend to the road ahead and maintain control of his vehicle; the need for regulatory definitions and classifications for bus body types; the limitations of medium-size buses in retaining and protecting passengers during rollovers; the need for technology to assist commercial drivers in maintaining control of their vehicles; and the need for event data recording in commercial vehicles to aid in accident reconstruction and safety research. As a result of its investigation, the National Transportation Safety Board makes recommendations to the National Highway Traffic Safety Administration.