Traffic is probably the visitor's biggest risk. Most drivers assume that you will get out of their way. Driving the wrong way on a one-way street is not uncommon, but stopping at stop signs is. So, look around before you cross the street!
Remember to take it easy on arrival, since the altitude can make you short of breath and cause headaches.
The central city is fairly safe, but as always keep an eye out for pickpockets and always hang on to your belongings. That being said, tourists should avoid traveling away from the city centre after dark.
