Puerto Rico operates under United States federal transportation regulations because it is a US territory. Drivers use the right side of the road. All distance and speed signs display measurements in kilometers and kilometers per hour, which differs from the fifty US states where miles are standard. Traffic laws mirror federal standards, including blood alcohol limits of 0.08 percent for drivers over twenty-one and zero tolerance for drivers under twenty-one. Police enforce seatbelt requirements for all vehicle occupants.
The island measures approximately 100 miles east to west and 35 miles north to south. A single primary toll highway, PR-22, runs along the northern coast from San Juan west to Hatillo, continuing as free highway PR-2 toward Mayagüez. PR-52 extends south from San Juan to Ponce as a toll road. Tolls on these expressways range from one dollar to three dollars per plaza. The AutoExpreso electronic toll system operates similarly to E-ZPass systems in northeastern US states. Drivers without transponders receive bills by mail to the vehicle registration address, with administrative fees added to the base toll amount.
Car rental agencies concentrate at Luis Muñoz Marín International Airport in Carolina, approximately nine miles from central San Juan. Major US chains operate terminals in the airport rental car center, which sits separate from the passenger terminals and connects via shuttle buses that run every five to ten minutes. Rental rates fluctuate significantly by season, with December through April commanding higher prices than summer months. A standard sedan rents for approximately forty to seventy dollars per day in low season and seventy to one hundred twenty dollars daily during peak winter months. Renters must present a valid driver's license from any US state or an international driving permit alongside a foreign license. Credit cards are required for the security deposit, typically a hold of two hundred to five hundred dollars.
Road conditions vary dramatically between the maintained toll highways and secondary mountain routes. PR-22 and PR-52 feature multiple lanes, regular resurfacing, and lighting. Mountain roads through Cordillera Central, including routes to access towns like Jayuya or Utuado, narrow to single lanes with switchbacks and deteriorating pavement. Route 143 through Barranquitas demonstrates typical mountain road characteristics with hairpin turns and grades exceeding fifteen percent. Flash flooding affects low-elevation roads during heavy rain events, particularly along the northern coast where drainage systems cannot accommodate intense rainfall rates that occasionally exceed three inches per hour.
Parking in Old San Juan presents the most significant challenge for drivers visiting the capital. The historic district occupies San Juan Islet, connected to the main island by three bridges. Street parking exists on a minority of blocks, marked by blue curbs, with two-hour limits enforced Monday through Saturday from eight in the morning to six in the evening. Multi-level parking garages operate at Doña Fela Parking near the cruise ship docks, La Puntilla Parking at the western tip, and Felisa Rincón de Gautier Parking on Calle Gilberto Concepción de Gracia. Garage rates run three dollars per hour with daily maximums between fifteen and twenty-five dollars. Meters accept quarters only, no credit cards or electronic payment.
Navigation applications function reliably across most of Puerto Rico because cellular coverage from AT&T, T-Mobile, and Claro extends to approximately ninety percent of the island's land area. Dead zones persist in the interior Cordillera Central, particularly between Adjuntas and Jayuya where terrain blocks tower signals. Google Maps and Waze contain accurate routing data for primary highways but occasionally display outdated information for rural roads that washed out during Hurricane Maria in September 2017 and were not rebuilt to original specifications. Route numbers in navigation apps sometimes conflict with posted signs because Puerto Rico uses both an older route designation system and a newer system implemented in the 1950s but never fully adopted on physical signage.
Gasoline stations cluster along highways and in every town center. The Puerto Rico Energy Bureau regulates maximum wholesale fuel prices weekly, but retail stations add their own margins. As of 2024, regular unleaded gasoline sells for approximately three dollars thirty cents to four dollars per gallon, roughly fifty cents to one dollar higher than contemporaneous mainland US average prices. Stations operated by Total, Puma, and Shell appear most frequently. Distances between stations along the southern coast between Ponce and Guayama occasionally exceed twenty miles, requiring attention to fuel levels when traveling this corridor.
Traffic congestion in the San Juan metropolitan area rivals major mainland cities during weekday commute periods. Morning backups on PR-52 northbound begin at the Caguas exits around six-thirty in the morning and persist until nine-thirty. Evening southbound congestion starts at four in the afternoon. PR-22 experiences similar patterns westbound in morning and eastbound in evening. The Luis Muñoz Marín International Airport exit on PR-26 generates bottlenecks throughout the day as rental car traffic merges with commuter flows. Weekend traffic to beach destinations in Luquillo and Fajardo creates eastbound delays on PR-3 beginning Friday afternoons.
Public bus service within San Juan operates under the Metropolitan Bus Authority, known as AMA. The system runs approximately thirty routes connecting Río Piedras, Santurce, Old San Juan, and surrounding municipalities including Bayamón, Guaynabo, and Carolina. Buses display route numbers on front and side panels. Cash fare costs seventy-five cents exact change. The Tarjeta Inteligente rechargeable card offers discounted fares of fifty cents per ride and can be purchased at Río Piedras terminal, Centro Gubernamental station, and select pharmacy chains. Service frequency varies from fifteen-minute intervals on major corridors like Route A5 between Río Piedras and Old San Juan to hourly service on peripheral routes. Evening service on most routes ends between eight and ten at night. Sunday schedules operate at reduced frequency with several routes suspended entirely.
The Tren Urbano represents Puerto Rico's only rapid transit system. This elevated and underground rail line opened in December 2004 and operates sixteen stations across ten point seven miles from Bayamón through Río Piedras to Santurce. Trains run every six to twelve minutes during peak hours and every twenty minutes during off-peak periods. Service begins at five-thirty in the morning and ends at eleven-thirty at night seven days per week. Single rides cost one dollar fifty cents. The system does not extend to Old San Juan or the airport despite original plans showing both connections. Plans to extend the system have been proposed multiple times since 2005 but no extensions have received construction funding as of 2024.
Público vans and cars provide informal shared transportation between towns across Puerto Rico. These vehicles gather at designated terminals in each town's center, typically near the main plaza. Drivers call out destinations and depart when vehicles fill to capacity, usually five to eight passengers. No fixed schedules exist. Fares depend on distance, ranging from two dollars for adjacent towns to fifteen dollars for cross-island trips like San Juan to Ponce. The público from Fajardo to San Juan costs approximately eight to ten dollars and takes ninety minutes under normal traffic conditions. This system serves primarily local residents rather than tourists because drivers assume Spanish fluency and knowledge of destination landmarks rather than specific addresses.
Ferry service connects the main island to Vieques Island and Culebra Island from the terminal in Ceiba, which replaced the previous Fajardo ferry terminal after Hurricane Maria. The Puerto Rico Maritime Transportation Authority operates two vessels on each route. The Vieques ferry departs three times daily in each direction, with crossing time of approximately one hour covering the nine miles across Vieques Sound. Culebra ferry service runs twice daily with crossing time of ninety minutes for the seventeen-mile passage. Tickets cost two dollars per person each way. Vehicle spaces cost fifteen dollars for cars and nineteen dollars for vehicles exceeding seventeen feet in length. Cargo ferry service operates separately from passenger service with different schedules. Reservation system for vehicle spaces opens two weeks before travel date through an online portal that frequently experiences technical problems during high-demand periods.
Private ferry companies including Vieques Fast Ferry and Culebra Water Taxi operate from San Juan and Fajardo, offering alternatives to the government service. These private services cost twenty-five to forty dollars per person one way, significantly higher than government ferries, but maintain more reliable schedules and operate newer vessels. The government ferry system experiences frequent cancellations due to mechanical failures, with the most recent extended suspension occurring from June through September 2023 when both Vieques vessels required engine repairs simultaneously.