There is surprisingly little guidance from the courts about just when the police can pull you over. It's clear that the police can stop you if they see you commit a traffic offense. But the courts have also said that police can pull you over if they see "a pattern of driving sufficiently erratic to raise a reasonable suspicion of impairment."
So what does that mean? Different judges apply it different ways, and police reports are full of vague statements like "the driver was weaving within his lane" or "the driver was hugging one side of the lane." If you can be stopped for moving around in your lane and you can ALSO be stopped for staying in the same place, it's pretty clear that the police have unbridled discretion to pull over anyone that they choose.
In a remarkable case decided January 31, 2017, the Florida Supreme Court clarified the situation, in an unusual way. On that day, they decided Wiggins v. Florida DHSMV. In doing so, the Supreme Court, for the first time, attached video to their written opinion, to show the state's judges what they meant. In this case, the Department of Motor Vehicles had ignored a video which showed that the defendant's driving was pretty good, and instead relied on the officer's description of the driving, which was pretty bad.
"Not Fair" said the Florida Supreme Court, and they attached the video so that every driver, every lawyer, and every judge in the state could see what kind of driving is NOT bad enough to get you pulled over.
In the video above, you can see that the driver stays to the right side of the lane, and he was driving 10 to 15 miles below the speed limit for the entire three minutes that the officer was behind him. But he signals for every lane change and every turn, and the Supreme Court noted that in the video, Wiggins drove "totally within the proper lines. Wiggins did not cross any lines, nor did he nearly hit the curb."
The case reflects an increasingly testy relationship between the judges on the Supreme Court, in which the Court majority alleged that the dissenters were trying to transform the appellate process into a factual dispute.
The single most important takeaway from the Wiggins case is that the Supreme Court, by a 5-2 majority, has posted video of the kind of driving which should NOT be enough to justify a police stop. Let's hope that the trial judges of the State of Florida are watching.