Yes very tragic.
The bad driver in the Honda was surely to blame, but I also blame the truck driver for not paying attention to the space in front of and around him. Had the truck driver been actively scanning ahead and on the sides, he would have seen the strange car coming down the on-ramp, and braked his car much earlier to avoid the car and warn other drivers. It seemed like he didn't pay attention until it was far too late.
I was driving a rental car this week in Nor Cal. Several times I had a Volvo, a truck, and a prius swerve into my lane, the drivers either not paying attention or just horribly drunk.
Fortunately I was very alert, the first time was at 11:30pm on the 101, just the Volvo and my rental car in the 4 lane freeway. The damn Volvo manages to swerve into my lane despite the freeway being empty. I saw it coming with my peripheral vision and honked my horn, and immediately slowed my vehicle down to avoid a collision. Same thing happend the other few times - once at 1pm, and another at 3pm. Horrible drivers.
You have to keep alert, and watch out for stupid people on the road.