There are a few preventative measure you can take before leaving the rental car lot that might save you a lot of frustration and hassle on the road. Some rental agencies will only perform a cursory inspection of the car upon its return. Often times they are more concerned with every nick or scratch on the exterior than normal wear and tear that can really affect the operation of the vehicle for the next customer. Before hitting the highway, it is a good idea to take a few minutes and check the basic components of the car: water levels, oil, brake fluid, air conditioning, belts, tires, and lights. Make certain that a spare tire and jack are present and in good condition.
City driving, especially around San José, can be hazardous and stressful due to the lack of signs, poor road maintenance, and local drivers who ignore the rules of the road. Buses will stop or merge into traffic with little warning; few people honor the lines painted on the roads; and one-way streets are rarely marked as such. It is recommended that visitors use the bus system when visiting downtown. Otherwise, take caution and stay calm while driving in the city.
Rural traffic is only slightly more tame, but an equal amount of care should be taken in these areas. Being patient and attentive is of the utmost import, especially considering the multiple forms of traffic that use common routes. It is not uncommon for rural roads to have the occasional herd of cattle shuffling across. Produce trucks creeping down the highway may keep you at a snail's pace for miles. Also be watchful at blind curves.
Road maintenance in Costa Rica is hardly up to snuff. Potholes, ruts, rocks and washboard roads make driving a challenge. When renting a vehicle, take this into consideration. Will you be staying on the major highways or will you be traveling to remote areas? If the latter is true, get a 4-wheel drive vehicle and something with a high clearance. Some rental agencies won't even let you rent an ordinary compact car if they know you are planning to visit the mountains and other destinations off of the beaten path.
Rental agencies will have booklets containing important traffic laws. As a general rule, always wear your seatbelt, follow the speed limit (100 kilometers per hour on multi-lane highways, 40-80 elsewhere), and pay attention to school zones (speed limit drops to 25 kph).
It is sometimes the case that policemen will wait for a car with rental plates to come along, then stop them for "speeding". The officer will then demand that the driver either appear at an inconvenient time and place or make an under-the-table payment then and there. Thankfully, the Transportation Ministry has tackled this problem by raising the salaries of policemen. In fact, an attempt to bribe a policeman can result in arrest. If a policeman tries to get you to pay him, get his ID number (they are required by law to show their ID upon request) or vehicle license plate number and report the officer to The Ministry of Transportation (257-7798 ext. 2376 or 2862). If you get a ticket, you can pay at any state-owned bank, or the rental agency will handle it when you return to them.