P.R. Laws tit. 9, § 5123
(a) It shall be illegal for any person to drive a vehicle or motor vehicle on any public highway at a speed of less than twenty (20) miles under the established maximum speed limit. This provision does not apply when safe driving requires reduced speed, or on a hill, or when driving a heavy motor vehicle which of necessity or in compliance with the law is driven at a slow speed. An infraction of this provision shall be punished as an administrative fault, with a fine of fifty dollars ($50).
(b) When the Secretary or the local authorities, determine, within their respective jurisdictions, on the basis of research on traffic engineering, which reduced speeds on any stretch of a public highway consistently hinder the normal and reasonable flow of traffic, the Secretary, or the local authorities may determine and declare a minimum speed limit under which no person shall drive a vehicle, except when it is necessary to drive safely or in compliance with the law. Any violation of a minimum speed limit shall be punished as an administrative fault with a fine of fifty dollars ($50).
(c) On those public highways in which there are two (2) or more traffic lanes in the same direction it shall be illegal to drive in the left lane at a speed below the maximum established speed limit on the public highway. This provision does not apply when reduced speed is needed for safe driving for justifiable reasons. A violation of this provision shall be punished as an administrative fault with a fine of one hundred dollars ($100).
History —Jan. 7, 2000, No. 22, § 5.03; June 3, 2004, No. 132, § 5, eff. 8 months after June 3, 2004.