Additionally, you admitted that your cars were traveling together. It is reasonable to assume that even if in different lanes, they were going at about the same speed. Generally, the officer's testimony will have more weight than yours and therefore, you need to reasonable challenge its credibility. The fact that it differs from yours does not really do that in itself. If you didn't see any motion by the officer yourself, you probably would be better off continuing to the next exit. You might also have been cited for parking on the side of the freeway when there was no emergency, except that the officer apparently expected you to pull over as well. If you could show an abuse of discretion by the court in believing the officer's testimony when it was obviously false and where no reasonable finder of fact would believe it, that's a different story. The judge's choice to believe one witness over another generally can't be appealed.

