I have been to Costa Rica many times. Both as a land tourist and on my
boat. I have driven the country from the southern border with
Panama to the Northern part almost to
Nicaragua. Driving around the capital of San Jose can be hectic like any other big city. Be careful in some of the outlying areas as manhole covers get stolen for scrap metal leaving a large hole in the road. As you get farther off the beaten path most rules of the road are ignored as in many Central American countries. Most Ticos are courteous drivers. The big rig drivers are another story. A lot of goods in CR come via the costal highway from
Panama. Trucks will pass each other two wide around blind corners. Nothing like coming around a bend and seeing trucks two wide. Try not to speed the cops will pull over a rental car as they let the locals fly by. I have driven thousands of miles throughout Costa Rica and never had a problem.