OK so i was going about 60 in a 40mph road, and when i saw a police car come to the intersection to make a right onto my road i slammed my brakes down to 40mph, and for about 1mile i went at 40 mph then made a right into the street live on, as soon as i made the turn the cop turned on his lights and pulled me over. He insisted i went 60 before i saw him and slowed down, and then went 50 after passing him (which i didnt because i kept looking at my spedometer it was 40/41) when i got into my street he said i went 57! He gave me a ticket for speed not prudent. When asked if i was clocked, he asked if i was a lawyer in a sarcastic manner. My question is, i had a cellphone to record the dashboard and i clearly enunciated the time and date while i was driving with the cop behind me (before he turned his lights on) i was afraid to show this to the officer incase he deleted it (or i got a ticket for using a cellphone while driving) the question is AM i allowed to use a cellphone in the car for purposes other than talking to someone or texting?

