Please Help Me If You're Good at Math

I'm going to fight a speeding ticket that I got last week that really pissed me off. I made a right turn and half a block down, a motorcycle cop got me for going 54 in a 45 which made no sense to me because there's no way I could have accelerated to 54 in such a short distance, even if I was flooring it (which I wasn't). So I'm trying to bring in the math to prove that by the laws of physics, I couldn't have been going 54. But I'm not very good at math. So please help me if you can!

The official literature on my car says that it goes 0-60 in 6.6 seconds. That's an acceleration of 9.09 mph per second.

Even though he has hiding in this driveway in the middle of a block, I just measured the distance to the next street (which was where I pulled over), which is 100 meters away (328.08 feet).

The minimum range for a radar gun is 50 feet. So I could only go a maximum of 278.08 feet from where I made the right turn, before he would be unable to clock me.

Velocity is acceleration x time. So this is my breakdown:

At 1 second (after turning), I was going at 9.09 mph. I traveled a distance of 13.332 ft.
2 seconds = 18.18 mph. 27.572 more feet traveled
3 seconds = 27.27 mph. 39.996 feet
4 seconds = 36.36 mph. 53.328 feet
5 seconds = 45.45 mph. 66.528 feet
6 seconds = 54.54 mph. 79.992 feet

I would have had to travel a minimum of 267.42 feet in order to be clocked at 54 miles per hour, which would mean it's within the realm of reason that I could have been going that fast if the radar gun had indeed been located 100 meters away from my start point.

Except he wasn't 100 meters away. He was 60 at most which should make it impossible for him to have clocked me at 54 miles per hour. I'm going to go out and measure the distance some time this week, but I'm trying to make sure that my math is correct, or the way I'm measuring the velocity/acceleration is correct. So if you're good at this stuff or have any tips, please help me! I know I wasn't going 54 mph because I wasn't gunning it and didn't have time to go that fast in the first place, but I just need to prove that there's no way that an acceleration to 54 mph in that short of a distance is possible.

Thanks!

ps--actually, what's strange is, I asked him about the radar and if he had my measurement on record from a radar but he just walked away and didn't answer my questions. So I don't know where he got 54 from.