Thats an easily beatable ticket. Some states have laws that work for the officers though (don't know about Bama) They have officers that are just for court, the one that gave you the ticket doesn't have to be there. Either way, I don't foree you loosing in court in less you have a bad bad history
Oh yea, and unless you're in a construction zone, the MINIMUM allowed speed on an interstate i've ever seen is 45, but I pulled this from Wiki"
Minimum design speed. Minimum design speed of 75 mph (121 km/h) in rural areas, with 65 mph (105 km/h) acceptable in rolling terrain, and as low as 55 mph (89 km/h) allowed in mountainous and urban areas. However, speed limits as low as 40 mph (64 km/h) are occasionally encountered, such as on I-59 through Laurel, Mississippi, Interstate 70 in Kansas in Downtown Topeka, Kansas, I-84 near Waterbury, Connecticut, Interstate 291 near Bloomfield, Connecticut nearing I-91, I-68 through Cumberland, Maryland, I-490 through downtown Rochester, New York and I-495 through New York City; and also on long bridges such as the Mackinac Bridge which carries the "Interstate 75" designation. Interstate 264 drops to 35 mph (56 km/h) in parts of Norfolk, Virginia, as does a brief segment of Interstate 93 in Lincoln and Franconia, New Hampshire.