The information in this report is preliminary and will be supplemented or corrected during the course of the investigation.
About 5:17 a.m., local time, on Sunday, October 23, 2016, a 1996 MCI 47-passenger motorcoach was traveling westbound on Interstate Highway 10 (I-10), near Palm Springs, Riverside County, California in the center right lane of the four-lane roadway. The motorcoach, operated by USA Holiday, headquartered in Alhambra, CA, was transporting 42 passengers from the Red Earth Casino in Thermal, CA to Los Angeles, CA. Around mile marker 32.51, the motorcoach approached a 2015 International Prostar truck in combination with a 2013 Utility 3000 R semi-trailer and collided with the rear of the semi-trailer. (See figure 1). As a result of this crash, the bus driver and 12 passengers died, 30 passengers were injured, and the truck driver was injured. The posted speed limit for I-10 in the vicinity of the crash was 70 miles-per-hour (mph) and the posted speed limit for vehicles towing trailers was 55 mph.
Figure 1. Aerial view of the truck tractor and semi-trailer and the motorcoach at final rest in the center right lane, (Source: California Highway Patrol).
Several minutes before the crash, east and westbound traffic queues had formed as a result of utility work that Southern California Edison Company was performing over I-10. The work consisted of moving electrical wires that crossed the road from a wooden pole structure to a steel pole, (see figure 2). California Highway Patrol (CHP) conducted simultaneous traffic breaks for east and westbound traffic to facilitate the work.
Figure 2. Westbound view of the new tubular steel pole structure at the intersection of the northwest corner of 20th Avenue and Diablo Road.
During the on-scene phase of the investigation, NTSB investigators conducted 3D laser scans of the undamaged truck, the damaged semi-trailer, and motorcoach. The CHP provided investigators with their initial 3D laser scans of the accident site and vehicles. Investigators also interviewed passengers and inspected records maintained by the motor carrier.
Parties to the investigation include the CHP, Caltrans, and the Federal Motor Carrier Safety Administration.
All aspects of the crash remain under investigation as the NTSB determines the probable cause, and continues to examine safety issues related to the crash. The NTSB is working alongside the CHP, which is conducting a separate, parallel investigation.