Issues for 1963- include section: Urban transportation research digest.

Results are presented of a study to review, summarize and evaluate the current state of the art of guardrail design and warranting criteria. Information necessary for the conduction of the investigation was secured from a search of the technical literature and by correspondence with individuals and agencies in the united states and abroad. Data and information are presented concerning present warranting practices, prevailing conditions of off-road vehicle motions, and guardrail performance as determined from accident studies, structural and physical characteristics of various types of guardrails in current use, results of full-scale barrier tests, and research programs currently in progress.

Various methods of assessing noise, loudness, and noise annoyance are reviewed and explained; sources, types, and intensities of traffic noise are noted; typical means of abatement and attenuation are described; design criteria for various land uses ranging from low-density to industrial are suggested and compared with the results of previous BBN and British systems for predicting annoyance and complaint; and a design guide for predicting traffic noise, capable of being programmed for batch and on-line computer applications, is presented in form suitable for use as a working tool. A flow diagram describes the interrelationships of elements in the traffic noise prediction methodology, and each element is discussed in detail in the text. The text is presented of a tape recording that takes the listener through a series of traffic situations, with such variables as traffic distance, flow velocity, distance, outdoors and indoors, and presence or absence of absorbers and attenuators.