The trooper in this case testified that he saw the subject car fail to signal the lane change when the car exited. But the federal district judge, after reviewing the Government's evidence and evidence produced by the defendants in detail, held that such an observation was not possible:
Based on the findings of fact above, Trooper Stahl’s testimony that he observed Webster commit a traffic violation is not credited and the Government has offered no other objectively reasonable basis to justify the stop. As a result, the stop is unconstitutional.
The Government tried to show how other facts discovered after the stop justified detention, but the judge held that any such discovery was tainted by the initial illegal stop and not sufficiently attenuated to independently justify the detention. As a result, the judge suppressed the evidence.
I wonder how common it is for police officers to just make up facts (like failure to signal or bad tag light)? In any case, this case shows how little it takes to really invade a person's privacy in the name of the war on drugs.