I'm planning a trip to North Carolina later this year and will probably be renting a car.
It seems like the speed limits are 70mph on interstates and 55mph on other roads. Coming from Europe these seem pretty low. I was wondering how strictly these are enforced (by radars, etc.) and what are the potential penalties, and if people generally stick to the limits.
Also, regarding alcohol limits, whilst I'm obviously not intending to drive drunk, I enjoy a glass of wine or two with my dinner - presumably this is acceptable?

yep it is slow and leeway may vary: interstate maybe 10-15 mph over. Go with the flow of traffic and dont wheave in and out -might go faster. If off the interstate be VERY careful since speedtraps are everywhere in North Carolina! The kind of traps where you are taken to the local court house and forced to pay a fine in cash or you go to jail.
Going through towns there may not be any leeway.
Also, make sure you speak English with a brit accent so they dont know your French... If you are able to pull that off try being personable and talking to folks -avoid your natural proclivity of condensation and aloofness.
As far as alcohol goes your nuts to even risk it. Good Wholesome Americans dont do wine with dinner.

Where speed limits are 70mph, I keep it under 85. If you travel at 85 plus or minus, you'll eventually get a ticket. This will cost you at least $100, but in some states will cost closer to $300, depending on your speed.
Drinking and driving is a serious offense here, and in many states can end up costing you more than $10,000 in legal fees, fines, and course fees. The old permissible limit for blood/alcohol content was .1 percent. I believe most states have now dropped that to .07 percent, meaning two drinks may put you over the limit.

I keep hearing this from Europeans, but have driven in every country in Europe and generally find they drive about the same speed as we do. Seems true even on the autobahns in Germany. That is to say, the average seems the same. Of course some people drive fast no matter where they are or what they're doing.
OP in the US/Canada I always stick to about 5 to 10 mph over and haven't had a ticket in ages.
Ed

OK, so the general consensus seems to be stick to 80mph and one drink max and I'll be fine.
To #1, I shouldn't have too much trouble with the whole accent thing, given that I'm British. Not too sure about the condensation (sic) though, but I guess you must know the French better than me, what with living in Antarctica and all that...

See FAQ posting 156: "Speeding and Traffic Cops in America"
The blood alcohol limit is usually .08%, which will usually allow for a couple of glasses of wine with dinner. #1 is wrong about Americans not drinking wine with dinner, by the way.

By the way, blood alcohol limits started at .15% and have been declining ever since. My favorite along those lines is Germany, where the BAL is 0.00% but you can buy beer at the rest stops on the Autobahn.
nope, most real Americans drink cat piss like Miller Lite! Maybe you were referring to wine coolers, Mr Snout?
I can guarantee you'll get a speeding ticket if you stick to 80 mph, even on the interstate. The speed limits are enforced fairly tightly and North Carolina state troopers love nothing more than giving tickets to out-of-staters, Duke students, yankees and foreigners.
I got a ticket near Greensboro for going 63 mph in a 55 mph section of the interstate - I was speeding up because the 55 mph zone was ending and I could see the 65 mph sign. For the other speeding ticket, I was caravaning with my friend as we were driving home after graduation. She was driving ahead of me and pulling away at about 80, I was going about 75. She got pulled over and I pulled over to wait for her. Price of being a good friend in North Carolina = $85 ticket and 2 more points on the license.
The only places in the state where I found you can push the limit are near the Virginia and South Carolina borders. Otherwise +5 over the limit is the most I will ever do there. I love North Carolina, but I can't ever live there again.