Warning - the lengthy post below is a verbatim C&P from something I posted a couple weeks ago regarding driving in Mexico. Some what is in here does not apply to your question specifically. Ignore whatever seems pointless and some of this will sound familiar since you have been to Cozumel.
I’m assuming from the OP that you are flying into Cancun and renting the car there, so I guess you can ignore all the posts about border crossings. I have been to Cancun several times; if you’ve never been there before, you’re in for a real treat. I have never rented a car or driven in Mexico, so I can’t address the OP specifically, but there seem to be many people who do rent cars and drive, so it can’t be that big of a problem. Just use your common sense. I’d make sure you’ve got good maps before you leave The States and then ask the rental agent about any construction or road problems along the routes you’d like to drive.
Below is UncleBeer’s standard Cancun advice, presented here free of charge. There are an awful lot of things to do in Cancun and plenty of regularly scheduled side trips available; you may find no need to drive once you get there.
You will need a valid U.S. driver’s license and a certified copy of your birth certificate, however a passport is better. Some of the banks will accept only a passport when cashing traveler’s checks. Don’t let that worry you though.
Nearly all businesses will take your American dollars and there are plenty of currency exchange huts around. Keep looking until you find the best rate and then exchange a few hundred dollars at once. If you buy something with dollars, make sure you ask the exchange rate first; often this is negotiable, especially at private vendors. With the exception of bars and restaurants, almost all prices are negotiable; don’t be afraid to haggle.
The public transportation (busses) run on no set schedule, but they go by, in the Zona Hotelera, about every two minutes, no joke. They’ll stop almost anywhere; all you have to do is get near a designated bus stop, jump in the road and raise your hand. They will also let you off anywhere you want; just stand up and yell’ “Alto, Senor.” The busses are very cheap, I think they were 3 pesos last time I was there, or about 40 cents. Taxis abound, but tell the driver where you’re going and get a price before you get in the cab, cab rides are also pretty reasonable.
There are over 300 restaurants within walking distance, if you are staying in the Zona Hotelera. All kind of price ranges. Not surprisingly, seafood is plentiful. Not to mention several beautiful shopping malls and a shitload of bars, nightclubs and not a few outdoor markets. There are also dozens, maybe hundreds of tours and sightseeing packages you may purchase. Shop around and compare; it really pays to be an informed consumer in Cancun.
Nearly every native you meet in Cancun speaks several languages. I have run into waiters and bartenders that speak Spanish, obviously, English, German, Japanese and Dutch. You will have no trouble making yourself understood, at least in the city. Out in the country, should you decide to drive there will be a different story.
The sun is intense. Make sure you take plenty of sunscreen, in several different SPF’s. If you have the white, flabby fishbelly like mine and want to spend any amount of time lounging on the beach or by the pool use a number 24 or higher for the first couple of days. Take along at least one good pair of sunglasses and a baseball cap or other head covering, too.
The island itself is absolutely gorgeous and completely spotless. In addition, it is extremely safe. The authorities and business owners have great incentive to keep that way; nearly 25% of Mexico’s hard cash enters the country though Cancun. I won’t say crime doesn’t exist, but again, use your common sense, much like you would in any large crowd. The greatest annoyance you’ll find will be the evil timeshare salesmen; these guys are ubiquitous and aggressive. If anyone offers you a free sightseeing tour or breakfast or something like that, just ignore them, or give them a quick, “No thanks,” and keep moving. If you stop to talk to these guys, you’ll have a hard time getting away from them.
The water and ice from nearly any place you’d eat or drink is probably safe, but I always drink bottled water. Obviously, stay away from the street taco vendors though. I would also stay away from leafy vegetables, any fruit that doesn’t have a rind or skin you can peel off and anything that lays on the ground while growing. If you do head into the backcountry for any extended period, you’re going to have to consider what food you’ll be eating. You might want to consider getting a Lomotil prescription from your doctor before you leave The States. A good case of Montezuma’s could ruin the whole trip.
Tipping practices are much like they are here in the states. 15% is considered standard, although the service and hospitality you will receive is exceptional. I have found very few restaurants in the U.S. where the service approaches anything like what you’ll experience in Mexico. Even the smallest and cheapest places will do everything in their power to accommodate you. And once you receive a table, it’s your’s for the night, if you choose. When you are ready to leave you’ll have to ask for the check; unlike here, where restaurants and bars try to turn over table quickly. It just seem to be a cultural thing; everyone refuses to be intimidated by time.
I highly recommend Cancun for anyone looking for a great and relatively cheap vacation. It’s a hedonist’s paradise. If you want some specific restaurant, bar or tour recommendations, I’d be happy to post them here. I will highly recommend one place now though, Iguana Wanna. It’s great for breakfast, lunch, an afternoon alcoholic beverage or even as a nightspot.
