List of highways in Puerto Rico
The highway system in Puerto Rico is composed of approximately 14,400 kilometers (8,900 mi) of roads and is maintained by Puerto Rico's Department of Transportation and Public Works (Spanish: Departmento de Transportación y Obras Públicas) or DTOP. The highway system in Puerto Rico is divided into four networks: primary, urban primary, secondary or inter-municipal, and tertiary or local (Spanish: red primaria, primaria urbana, secundaria o intermunicipal, and terciaria o local, respectively). Highways may change between networks and retain their same numbers.
Route number shields 
Puerto Rico roads are classified according to the network they belong to. Thus there are four types:
- Primary Roads
- Urban Primary Roads
- Secondary (or inter-municipal) Roads
- Tertiary (or intra-municipal) Roads
In this regard a primary road is one which is part of the Primary Network, an urban primary road is part of the Urban Primary Network, etc. The same highway, such as the one leading from Ponce to San Juan, may change between networks, but the highway will continue to have the same number. Thus PR-1, one of the roads between Ponce and San Juan, is signed as Urban Primary ( PR-1) inside the Ponce city limits, then it is signed as Secondary ( PR-1) in Ponce's rural barrio Capitanejo, and then it is again signed as Urban Primary ( PR-1) on its entry into the town of Santa Isabel.
Primary roads are numbered 1 through 99, secondary roads are numbered 100 to 299, and municipal (tertiary) roads are numbered 300 to 9999.
Until 1999, all non-tolled numbered highways in Puerto Rico had the same route shield, a square with a white-on-black half-circle with the route number in the bottom two thirds and a map of Puerto Rico with the words "Puerto Rico" written inside in the top third.
Road maintenance 
All Puerto Rico roads, regardless of the network they belong to are maintained by the centralized, Commonwealth-level, Departmento de Transportacion y Obras Publicas (DTOP). Municipal governments are not responsible for maintenance of roads within their territory whether or not the municipal government is an autonomous government or not; DTOP is the responsible agency. The DTOP maintains a network of regional offices throughout the island which carry out DTOP work within their multi-municipality region. Municipal governments are only responsible for maintenance of city and town streets within their jurisdictions. On occasion, the central government has entered into MOAs with municipal governments for the collaborative maintenance of some state roadways within their municipalities.
Puerto Rico has 410 km (250 mi) of Interstate highways. There are three designated Interstate Highways in Puerto Rico. As with Interstate Highways in Alaska and Hawaii, these routes do not connect to the rest of the United States Interstate Highway System, but still receive funding in a similar fashion to the Interstates in the contiguous US.
As with Interstate routes in Alaska, Puerto Rico Interstate routes are unsigned. The designated routes of the three routes — officially PRI-1, PRI-2 and PRI-3 — run along various combinations of Puerto Rico routes. They do not follow the rules of even and odd numbers determining direction used in mainland United States. Per Section 103(c)(1)(B) (ii), Title 23, United States Code (23 U.S.C.) Puerto Rico is exempt from the design standards of Section 109(b).
Puerto Rico's interstate routes are not to be confused with Puerto Rico Routes PR-1, PR-2, and PR-3. These are other major highways in Puerto Rico. Originally, these three routes formed Puerto Rico's entire interstate system, however, portions of Puerto Rico's interstate highways have since been reassigned to various freeways bypassing those routes.
Route table 
|Interstate PR1|| PR-52
|71.08||114.39||PR-2 in Ponce||PR-2 in San Juan (PR 22/PR 18 interchange)|
|Interstate PR2|| PR-2
|138.13||222.30||PR-1 in Ponce||PR-3 in San Juan (PR 1/PR 26 interchange)|
|Interstate PR3|| PR-53
|65.27||105.04||PR-3 in Humacao||PR-2 in San Juan (PR 1/PR 26/PR 66 interchange)|
Expressways in Puerto Rico are controlled-access highways, or expressways. Many, but not all, of them are tolled. All Puerto Rico expressways are signed either as primary or as primary urban routes. As of August 2010, the current expressways were:
- PR-2 (From West Ponce (Tuque) to Hormigueros and a small portion from Guaynabo to San Juan)
- PR-5 (Tollway)
- PR-20 (Tollway)
- PR-22 (Tollway)
- PR-52 (Tollway)
- PR-53 (Tollway)
- PR-66 (Tollway)
List of Highways 
Below is a list of some highways in Puerto Rico along with the municipalities where they begin and end.
Primary highways 
Secondary highways 
Secondary highways follow a general grid, unlike primary highways which are random throughout the island. They begin from west to east, for example, PR-100 is in the southwest town of Cabo Rojo, whilst PR-198 is in Juncos, Las Piedras and Humacao in the eastern part of Puerto Rico. Some "violate" the order, like PR-199 which lies in Guaynabo and San Juan. Secondary highways are in the order from 100 to 299, which the highest number (PR-251) being in the easternmost part of Puerto Rico, in Culebra.
Tertiary highways 
Tertiary highways also follow a general grid, and are generally considered municipal highways. Towns which do not border the Atlantic Ocean or the Caribbean Sea, especially in the mountainous area, may overlap this grid, for example Ciales may have both highways in the 600-699 grid and the 500-599 grid, depending where they begin further north or further south. Generally along the areas where the highways are, the lower the number, the more south it is. Culebra is the only town in Puerto Rico that does not fall in any of the regions, for only PR-250 and PR-251 are the main routes. The entire immediate metropolitan area of San Juan with the exception of Caguas falls in the 800 region, while the entire east coast (north and south) east of San Juan, Caguas and Patillas fall in the 900 region. This is because the eastern portion of Puerto Rico has a southeastern coast which goes to the west from Humacao, which hardly defines where the Vieques Passage and the Caribbean Sea meet along the coast. Yabucoa is in the exact south-southeast area and lies in the 900 region, while Maunabo overlaps the 700's and 900's regions. Vieques, separated from the main island, has some highways in the 900 order.
- Puerto Rico Small Traffic Route Markers
- Puerto Rico Small Traffic Route Markers
- Puerto Rico Road Photos
- Autoridad de Carreteras y Transportacion (December 22, 2004). "Guias para la Seleccion e Instalaccion de Rotulos de Orientacion (Suplemento al MUTCD 2003)" (PDF) (in Spanish). Departamento de Transportación y Obras Públicas. p. 2. Retrieved March 14, 2010.
- Autoridad de Carreteras y Transportación (December 22, 2004). "Guias para la Seleccion e Instalaccion de Rotulos de Orientacion (Suplemento al MUTCD 2003" (PDF) (in Spanish). Departamento de Transportación y Obras Públicas. p. 1. Retrieved March 14, 2010.
- Autoridad de Carreteras y Transportación Estándares de Ingeniería. "Chapter i: General Design Criteria" (PDF). Manual de Diseño (in Spanish). Departamento de Transportación y Obras Públicas. Sections 1-03.01, pp. 1-2.
- "Municipal Ordinance Number 52, Series 2009-2010. Primera Hora" (PDF) (in Spanish). Autonomous Municipality of Ponce. April 28, 2010. p. 59.
- "Oficinas Regionales" (in Spanish). Departamento de Transportación y Obras Públicas. Retrieved August 22, 2010.[dead link]
- "Act Propone Diseño de Mejoras Geometricas Para Agilizar el Transito en las Rampas de Acceso de la PR-52 Hacia y Desde Juana Diaz" (Press release). Departamento de Transportación y Obras Públicas. November 16, 2010.
- "Municipio de Ponce Repavimenta la PR-2". El Sur a la Vista. Ponce, Puerto Rico (in Spanish). September 16, 2011. Retrieved September 19, 2011.
- "Section D: Puerto Rico Highways" (PDF). Latin America Trade and Transportation Study. Mississippi Department of Transportation. March 2001.
- DeSimone, Tony (April 6, 2011). "Table 3: Interstate Routes in Each of the 50 States, District of Columbia, and Puerto Rico". Route Log and Finder List. Federal Highway Administration. Retrieved July 4, 2012.
- DeSimone, Tony. "Additional Designations". Route Log and Finder List. Federal Highway Administration. Retrieved March 14, 2010.
- "Table 1: Main Routes of the Dwight D. Eisenhower National System Of Interstate and Defense Highways as of October 31, 2002". Route Log and Finder List. Federal Highway Administration. June 4, 2012. Retrieved July 4, 2012.