Kentucky, along with most other states, has in the past relied on the American Association of State Highway and Transportation Officials' (AASHTO's) "Guide for Selecting, Locating, and Designing Traffic Barriers" for guidance in the installation of guardrail. Additional information related to barrier selection and installation was recently published in AASHTO's "Roadside Design Guide". However, considerable judgement is required for application of this information, and it was determined that significant benefit could be derived from development of guidelines representative of conditions in kentucky. Listed as follows are significant results from this study: (a) results from a previous survey of guardrail standards and guidelines were summarised and it was found that only a few states suggested use of reduced guardrail standards that did not conform to AASHTO's barrier guide; (b) warranting guidelines for clear zones and embankments based on kentucky accident severities and costs were developed from a computer program included as part of the "roadside design guide"; and(c) a procedure was developed to identify and rank in priority order highway sections in need of guardrail (details to support the identification and ranking of the procedure were included in the full research report prepared for the Kentucky Transportation Cabinet in co-operation with the Federal Highway Administration). This procedure was based on determination of locations with critical numbers and rates of run-off-road accidents, conduction of a field survey to tabulate hazard-index points, determination of improvement costs and benefits, and performance of a cost-effectiveness analysis.
Abstract