Not at all. It is actually often that once an officer is going to make an arrest for a criminal offense that they don't cite the lower traffic infraction (though it would be good practice for the officer to do so as it may affect his/her credibility later on).
No, it is not grounds for dismissal; but the officer may be forced to prove that he was justified in making the stop. Unfortunately it is pretty easy for an officer to prove up a speeding stop in most cases.
The more crafty officers will give you a warning for the initial traffic violation they claim justified the stop. A warning will protect the officer from what Mr. Lieberman suggests, a later attack on their credibility. However, as the other lawyers said, commonly the traffic offense used to pull you over is ignored since it is simply additional paperwork for the officer to manage.
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