is the context of how a road is used, that is, the purpose of a road. The purpose of a road is indicative of whether a road is a municipal road or not. In its strictest meaning, the term municipal roads refers to roads within a municipality's urban center that provide access from one urban neighborhood to another urban neighborhood within the same urban area (city, town, poblado, etc.), while in the larger context of the State highway system, municipal roads refers to roads that “provide access to the main urban area of a municipality from peripheral communities” (that is, tertiary roads). Municipal roads are maintained by the municipal government where those roads occur, while tertiary roads are maintained by the State government. As stated under the section Road maintenance, at times the State government has entered into Memorandums of Agreement with municipal governments for the upkeep of a State tertiary roadway (note this is a State-owned road that runs entirely within a single municipality), but this does not make it a municipal road—the road continues to maintain its State signage and ownership. Expressways Highways with control access fall into three types: An expressway is an arterial highway with full or partial control of access. Expressways with full control of access are termed freeways. If the freeway charges a toll for its use, it is called an . Most tollbooths accept the , an electronic toll collection system, to avoid traffic congestion. Toll roads between San Juan and Arecibo, and between San Juan and Ponce were envisioned by J. Raymond Watson, a Puerto Rican engineer, in 1970. All Puerto Rico expressways are signed either as primary or as urban primary routes. List of highways Below is a list of some highways in Puerto Rico along with the municipalities where they begin and end. Primary highways Primary roads are numbered in the 1 to 99 range and are distributed randomly throughout the island. Secondary highways Secondary roads are numbered in the 100 to 299 range. Unlike primary highways, which are numbered randomly throughout the island, secondary highways generally follow a grid pattern. They begin from the southwest portion of the island with PR-100 and increase in number as you progress in a northeasterly fashion. PR-100 is located in the southwestern town of Cabo Rojo, whilst PR-198 is in Juncos, Las Piedras and Humacao in the eastern part of Puerto Rico. The