From a legal perspective, the driver would likely be facing a charge of Unsafe lane change, with that I agree. But from the insurer's FDR's it would at best be a 50/50, (sideswipe type of collision), to the driver hitting the merging vehicle from the rear, being declared as a at fault collision. From an insurer's point of view, if you rear ended the vehicle, then YOU should have observed the vehicle and had you been operating in a "safe and prudent manner" you should have avoided the collision.
The legal and insurance rules are often at polar opposites.
The legal and insurance rules are often at polar opposites.
An unsafe lane change at much lower speed, in front of an approaching vehicle going much faster in the adjacent lane, is an example of the vehicle that was hit from behind being responsible for the collision.