I've been reviewing the ticket that I recieved on monday. I've been able to determine the method the plane used to determine my supposed speed.

Have any of you ever tried to test your own 0-60 foot times. They are probably off by atleast 2-4 tenths. Have you tried to time your own 1/4 miles times? probly off by about the same, but a smaller percentage. In other words the longer the distance the less percentage you will be off.

The plane used to monitor speed on the bridge between baton rouge and lafayette only checks your speed for a 1/8th mile stretch. My time was 5.61 seconds.

I've done some math please review and comment.

60 mph = 5280ft per min
5280ft per min = 88 ft per sec

80 mph = 5280 * 1.333 = 7038.24ft per min
7038.24ft per min = 117.304ft per sec

ticket stated 80mph in a 60mph zone
also stated time of 5.61 seconds

5.61 seconds * 117.304 = 658.075 ft

1/8th mile is 660. Assume tracking area is 1/8th mile

reaction time can very ? atleast +- 2/10 sec. So actual time for 8th mile could be
as little as 5.21 or as much as 6.01.

if you coverd 660ft in

5.0 seconds speed would be 660/5 = 132ft per second
132ft per second *60 seconds = 7920 ft per min
7920ft per second / 5280 =1.5
1.5*60mph = 90 mph

5.1 seconds speed would be 660/5.1 = 129.4ft per second
129.4ft per second *60 seconds = 7764 ft per min
7794ft per min /5280 =1.47
1.47 * 60mph = 88.2mph
5.2 seconds speed would be 660/5.2 = 126.9ft per second
126.9ft per second 8 60 seconds = 7614 ft per min
7614ft per min / 5280 = 1.44
1.44 * 60 mph = 86.4mph
5.3 seconds speed would be 660/5.3 = 124.5ft per second
124.5ft per second * 60 seconds = 7470 ft per min
7470ft per min = 1.41
1.41 * 60mph = 84.6 mph

The above demonstrates that a .1 sec total reaction time differance in a 1/8th mile stretch
results in a 1.8 mph differance.

therefore the following times in a 1/8th mile stretch would result in the corisponding speed

5.0 = 90.0mph I would think that the collume to the left would illistrate
5.1 = 88.2mph just how prone to error the method used to determine auto
5.2 = 86.4mph trafic speed is.
5.3 = 84.6mph
5.4 = 82.8mph
5.5 = 81.0mph
5.6 = 79.2mph
5.7 = 77.4mph
5.8 = 75.6mph
5.9 = 74.8mph
6.0 = 72.0mph
6.1 = 70.2mph
6.2 = 68.4mph
6.3 = 66.6mph
6.4 = 65.8mph
6.5 = 64.0mph
6.6 = 62.2mph
6.7 = 60.6mph
6.8 = 58.8mph
6.9 = 57.0mph
7.0 = 55.2mph

my cut and paist did not work as well as I had hoped, but I hope you get the idea.

 

This is definitely OT, please keep it there...I don't feel like reiterating it anymore, eventually I'm just going to move posts over.

Jay