This question is hilarious! It may be OK in some video games but not in real life. You really have to let granny cross the street even after the light turns green. Otherwise, you will be subject to criminal prosecution and civil liability including serious punitive damages.
Believe it or not I have been asked this question several times and represented client's who were hit in the crosswalk. Short answer is "NO". You may not plow down a pedestrian as they cross the street in the crosswalk ...... even though they are crossing at the wrong time. The law requires that you "mitigate" the damages. That means that you have a duty to avoid an accident if it is reasonably within your power to do so. Good question though.
Mr. Lundeen is licensed to practice law in Florida and Vermont. The response herein is not legal advice and does not create an attorney/client relationship. The response is in the form of legal education and is intended to provide general information about the matter within the question. Oftentimes the question does not include significant and important facts and timelines that, if known, could significantly change the reply and make it unsuitable. Mr. Lundeen strongly advises the questioner to confer with an attorney in your state in order to insure proper advice is received.