Deprivation of Rights under Color of Law.
Title 18, U.S.C., Section 242.
This is the Federal statute that fabrication of evidence is prosecuted under, including a fabricated report dealing with a minor traffic accident. Fabrication of evidence, of any kind, is a violation of a person's Fourth Amendment Rights.
It also applies to extortion (as does the Hobbs Act). The motorcycle rider was extorted into "forgetting" the incident happened, under official threat of receiving tickets.
With the right lawyer pushing on this, it could turn very wicked for the officer very quickly.
At the least, the officer will most likely lose his job as this was criminal conduct. The city will probably want to distance itself and make a small settlement payment to the rider to prevent a civil action as well.