Take a virtual drive (via Google maps street view) of that stretch of I-70 where the crash occurred.
There are no hills there that could significantly block forward vision, particularly from the elevated cab of a semi.
Drivers ahead of the truck who caused the crash were perfectly able to slow down and not crash, so forward vision was not an issue for them.
The driver who caused the crash simply wasn’t paying attention. It was his fault.
It is amazing to me that there are not more crashes around here in Washington State. We have got plenty of view obstructing hills, but that is not the problem.
The bad drivers who are not smoking pot are playing with their cell phones and a lot of those who are smoking or "vaping" pot are also playing with their cell phones. And by playing with their cell phones, I do not mean that they are merely talking on them. They are looking down at their phones while they are texting or trying to get the phone to do something. The other day I even saw some guy with a laptop in the passenger's seat and he was doing something with that while driving.
You can tell who they are even when you can't see what they are up to because of tinted windows. One minute they will be leaving an excessive amount of following distance or driving 10 mph below the speed limit. The next thing you know they are doing 20 mph over the speed limit weaving in and out of traffic and passing on the right even when there is plenty of space to pass on the left. Then they will start driving slow again.
It's a bit more complicated than that. Cars use Hydraulic brakes, Trucks use pneumatically actuated systems. The Air systems adds a little more delay to the brake activation, this typically works out to about double the stopping distance for vehicles equipped with Air brakes compared to hydraulic systems. Sudden stops in a heavy vehicle can be very nerve racking as depending on how your load is arranged you can have the load trying to get in front of you (jacknife).