Abstract: A guardrail system including a rail and rail connectors is described wherein the rail is formed of several elongated tubes which are integrally molded at the tube sidewalls. The tubes preferably have polygonal cross-sections with sidewalls situated in horizontal and vertical planes, with the vertical sidewalls of the various tubes staggered at different depths within the rail. Connections between rails may be achieved by internal connectors which fit within the tubes of adjacent rails, and/or by use of external connectors which receive the ends of adjacent rails. Such internal and external connectors may also be used to reinforce damaged rails to restore their performance characteristics.