Where do I find information on wood guardrails used in highway/bridge construction?

• Hand rails and guard rails used in highway/bridge construction, have criteria available from the sources below.
  
  AITC's Glued Laminated Timber Bridge Systems Manual. (303) 792-9559. http://www.aitc-glulam.org/
  
  Wood Transportation Structures Research Website: http://www.fpl.fs.fed.us/wit/index.html (304) 285-1591. na-wit@fs.fed.us
  
  See timber bridges