We’ve been in VA just outside DC for the last year and that law is in full effect here, and they are SERIOUS about it. You’d better move over, and if you opt for option 2 (slow down to a reasonable speed) you’d better be down around 15 or you’re going to find yourself pulled over a mile down the road. They often have a secondary officer/etc nearby watching for exactly these sorts of violations, and they go after the folks who don’t move over or just give a quick tap on the brakes.

It’s all about the safety of the officers/personnel so idiots don’t go ripping by at 75 with 5 feet to spare.