moving violation

State: NH
Town: Portsmouth

I was travelling north on I-95 in heavy traffic in the right lane. I approached my exit at 15 mph over the posted limit but my speed matched traffic in front, to my left and behind me. The two lane ramp was empty, and a straight path about one half of a mile long before it reached a rotary. As I exited I coasted immediately noticing two vehicles behind me exiting as well. A Portsmouth town officer was parked in some trees about 300 ft. from the beginning of the ramp and clocked me at 70 mph. The officer didn't ticket me for speeding but cited me for reckless endagerment and now I risk loosing my license for a basic moving violation. This seems excessive. Do I have any valid arguement to work with?

KF