As for #1, here on the freeways, if 2 cars are driving next to each other under the speed limit at the same speed, they can get busted for impeding traffic. The law also states the speed is governed by: 1. posted limit, 2. flow of traffic, 3. weather/street conditions. You can be pulled over for going 75 in the left lane on a 65 road if everyone else is going 85 because of "improper use and impediment of the passing lane" or something like that. Friend's wife got busted for it.
Amazing the kinds of things you can find when you read your state traffic charter. I got pulled over a while ago, and was able to recite the law number that protected me in that case. The cop invited me over to his car to review the code, and one half hour later, he gave up saying "You know this better than I do, you're free to go" no warning, no ticket, nothing, because what I was doing was legal and could recite the section (41.6.140.b), even though he didn't think it was. (Tip: Don't try this at home)
Fun Fact: Statistics show that cars going under the speed limit have a higher chance of getting in wrecks than cars going over.
Speeding laws were originally designed as precautions to keep cars going what was safe speeds for those cars to drive. Though the safety features of cars have evolved to allow safe, relatively quiet travel at 100 mph (without the engine exploding, and the floors falling out

) the old 55 mph limits are more or less now just used to give people tickets to increase state revenue. (If you have any better reason to explain "quotas" I'd like to hear it, 'cause I'd rather deal with a viligante system than bored cops w/ quotas) Safety became economics. Law became a b*tch.
Yes, there are cool cops around, we just don't meet em very often 'cause they're not the ones who pull you over for not physically turning your head both ways before proceeding at a yield sign at 3 in the morning.