Probable cause is the standard applied when it comes to arrest. Reasonable suspicion is all that is needed for a traffic stop. Staying stopped at a green light is almost certainly reasonable suspicion. However, it may be possible to fight your case on other grounds. Consult with an attorney. Good luck.
Yes - that type of driving, similar to driving way too slow compared to the speed of other drivers, is enough for the police offer to have reasonable suspicion to many things (ie: possible drunk driving etc). Contact an attorney for representation.
This is not intended to be legal advise or as legal representation. I am a California personal injury attorney . Be aware that every state has its own statute of limitations; and statutes & case laws that govern the handling of these matters.
Unfortunately, that is enough to stop for reasonable suspicion of driving under the influence. Put the officer to the test, however, by running a motion to suppress!
My answer to your question does not establish and attorney-client relationship.