Most motorists in the San Francisco and greater Bay Area probably know that inattentive or distracted driving is a bad idea even when one is operating their private car. In some cases, someone who is just drifting off or is on one's phone can completely miss that the vehicle in front of them has come to a complete stop and slam into that vehicle's rear bumper. No doubt, there have been other cases in which a driver has a close call, realizing just in the nick of time that they are about to have an accident and are able to slam on the brakes.
When it comes to large trucks, drivers have even less leeway to take their eyes and minds off the road, even for a second. This is because, due to the laws of physics, it simply takes a much longer distance for a truck to stop than it does a passenger car, particularly at higher speeds like those typically traveled on the highway. Trucks, after all, weigh much more, and it takes more energy to stop them once the brakes are applied.
By way of example, a car traveling 65 miles per hour takes about 245 feet to stop once a driver hits the brakes. In contrast, a truck traveling the same speed will require 454 feet, about the length of one and a half football fields, to stop. The end result is that what might be a near miss for an inattentive driver in a car may be a serious or deadly collision for a trucker who won't be able to stop.
The upshot is that, to prevent truck accidents, semi drivers and others who operate heavy commercial vehicles simply must pay attention to their driving at all times. Not doing so can result in serious truck accidents for which these drivers can be held financially accountable.