Abstract
This paper looks at some safety- related treatments and designs and attempts to define what is known with some certainty and what remains to be learned through research. Areas reviewed include lane and shoulder width and type, sideslope design, clearzones, removal or shielding of certain roadside obstacles such as utility poles and sign posts, roadside barriers, bridge width and railings, horizontal alignment, intersection design parameters, pavement surface condition and edgedrop, and driver information systems.