Options for getting around the country include bus service, 'gua-guas' pronounced "Gwa-Gwas": small battered vans or trucks that serve as a collective taxi running fixed routes that are very cheap but can also be very overloaded, domestic air flights and charter air service. There is no rail system in the country. Most towns and cities have regularly scheduled bus service, if not by one of the big bus companies, then by gua-gua (http://horariodebuses.com/do). The bus lines are most often simple, independently run operations, usually only connecting two cities within a region Southwest, East, North or between one city and the capital with stops made for any towns on the route. Because of the geography of the country, to get from one region of the country to another you have to go through the capital.
Cars may be rented through Hertz, Avis, Prestige Car Rentals (http://www.punta-cana.us/...) other agencies in Santo Domingo and other major cities. Gasoline, unlike most countries that were converted to an Metric System like the Dominican Republic, is sold in US Gallons. However, it's expensive and often costing upward of US$5.75/gallon as of March 2011. Some roads, especially in remote areas, are fairly dangerous often without lane divisions and many people tend not to respect oncoming traffic. However, road conditions on most major highways are roughly similar to road conditions in the United States and western Europe. However, potholes and rough spots are not rapidly repaired and drivers must be aware that there are a significant number of rough spots even on some major highways. However, there are a number of very good roads such as DR-1 which is a four lane highway connecting the cities of Santo Domingo and Santiago and can be traveled with no trouble. Highway DR-7 is an excellent toll road opened in late 2008. It goes from just east of Santo Domingo north to near Sanchez. From there, you can go east to the Samana peninsula or west along the northern coast of the DR and costs about US $11.
Probably the biggest challenge that an international visitor to the Dominican Republic will face if he or she chooses to rent a car is not so much dealing with automobile traffic, but rather avoiding accidentally running over pedestrians who cross poorly-lit streets and highways in the evening and night time hours. Lack of head/taillights on cars and especially motorcycles is also not unusual and with motorcycles this makes them extremely hard to spot. The best recommendation is not to drive after dusk. Outside of Santo Domingo, the motorbike motoconcho is an extremely common form of travel. If lost, you can hail a motorbike driver motochonchista and ask for directions. You will be taken to your destination by following the bike. A tip is appropriate for such help. Remember that many of these motorbike drivers look upon road rules as only recommendations. However, driving in the Dominican Republic should not be particularly difficult for experienced drivers from North America or Europe, though local drivers in the Dominican Republic are often reckless and undisciplined and accidents, even fatal ones, are relatively common, especially with big cities with few traffic lights, often either malfunctioning or non-functional at all.
Guaguas (Local Buses)
Guaguas are the traditional means of transport in the Dominican Republic. Guaguas will be filled to the brink with people and luggage; expect to squeeze to fit more people who will be picked up en route. If you prefer authentic experience over comfort, travelling by guagua is the right choice see (http://horariodebuses.com).
Guagua comfort can range from air conditioned with leather seats to a bit worn down with open window air breeze cooling. Traveling with guaguas is safe, and tourists are treated friendly and get helped out.
You can also hop on mid way if you know where to stand on the route and gesture the driver; tell the conductor your destination and he'll tell you where to get off and how to switch guaguas; sometimes you'll have to ride across town to another bus station.
Prices are modest, around 100-150 pesos for a 1-2 hour ride. Since most guaguas are minibusses, you might have to stow your luggage on a seat; in this case you might have to pay a fee for the occupied seat. Larger routes get serviced by normal sized buses with a separate storage compartment.
Be aware that guaguas stop operating at dusk. Plan your trip with enough slack that you will be able to catch your last guagua when the sun is still up.
The guagua network is organic and does not require you to go through the capital; you might have to change several times though, as guaguas usually only connect two major cities.
Caribe Tours (http://www.caribetours.com.do/), based out of the capital, is the biggest bus company, and has coverage in most regions that are not well-served by the other 'official' bus companies. Unlike taxis and gua-guas, Caribe Tour rates are fixed by destination and are extremely reasonable due to government subsidies. Expect to pay under 250 pesos Dom or US$10 for even the longest trips. Caribe Tour buses typically run from 7AM to 4PM with departures approx. every two hours and cover most major cities. On longer trips, expect a short 10 minute stop for coffee and lunch. Buses are fairly luxurious with movies playing for the entire trip and air conditioning which can be extremely cold - bring a sweater. Another option is the slightly more expensive Metrobus bus company (http://www.metroservicios...). Metrobus serves the northern and eastern part of the country. The 'unofficial' gua-gua system covers nearly every road on the island for some moderate savings if you don't mind being packed in.
In short, bus services across the country are comfortable and a good value. The buses are clean, air conditioned bring sweater, usually play a VHS movie, and are pretty inexpensive, costing no more than $300 pesos one way cross-country less than $10.
Taxi services are available but potentially dangerous when dealing with unlicensed drivers. In all cases, it's a good idea to go with a licensed driver and negotiate a price for your destination before you leave. Good drivers are often easy to identify by licenses worn around the neck, uniforms, and clean air conditioned vehicles. When calling a taxi company, you will be given a number to verify your driver. When being picked up, make sure your driver gives you the right number as 'false pickups' are often a prelude to robbery.
Another way to get out and about is to book an excursion with one of the many representatives at most local hotels and resorts.