This is great in theory, but it doesn't really work when driving on a lot of roads, because if you create a large space in between you and the next vehicle, on a single-lane-each-direction highway, people are going to pass you and jump in front. Then what? Slow down again to create a 3-second space? Rinse and repeat? No thanks.
In practice, very few people maintain this amount of space (or anything near it) on semi-crowded one-lane highways where the speed of traffic is approximately the speed limit.
Again, this "Move Over Law" is needlessly causing people to slam on the brakes on the highway despite no danger in front of them, which is a huge safety hazard being introduced.
At the same time, the law doesn't appear to be saving any lives of law enforcement, for the reasons I already stated earlier.
The law is well-intentioned, but unfortunately both ineffective and somewhat dangerous. That's why it's now been perverted into a money-making opportunity for local departments and counties.
When passing traffic laws, the practical use should be everything. Any law which causes more harm than it solves should not be on the books. Additionally, any law mostly present for revenue also shouldn't be on the books.
Too many people have been tricked into supporting money-generating traffic laws via knee-jerk support for "safety".