From the article:
Police said the bus was ferrying 16 people. "Everybody on the bus was on the upper deck," Burke said. "It was a beautiful Friday night. This was a very tragic accident."
Witnesses gave conflicting accounts about whether they were standing on the deck or on the seats, Burke said. As the bus traveled westbound on the Southeast Freeway, passing under the 11th Street bridge, the men's heads struck the overpass, resulting in massive trauma, police said
Um, if they were sitting down, why didnt anyone else suffer head trama? Since all 16 were on the upper deck, I'd assume others would of gotten injured also. I think they were standing up or on the seat. Who knows for sure.