Improving Truck Safety at Interchanges

DTFH61-88-R-00072This report offers highway engineers guidance in designing interchanges so as to reduce the likelihood of truck accidents on highway interchanges. This report summarizes research showing that the interaction between truck dynamics and interchange geometry can contribute to rollovers, jackknifes, and other loss-of-control accidents. Engineers can apply corrective actions to six specific ramp design features that were found to contribute to truck accidents: poor transitions to superelevation, abrupt changes in compound curves, short deceleration lanes preceding tight-radius exits, curbs placed on the outside of ramp curves, lowered friction levels on high speed ramps, and substantial downgrades leading to tight ramp curves. Countermeasures for these design problems include incorporating a greater safety margin into formulations for side friction factors, reviewing and modifying posted speed limits, improving curve condition and downgrade signs at interchanges, increasing deceleration lane length, overlaying curbs with wedges of pavement or eliminating curbs altogether, resurfacing ramps with high-friction overlays, and redesigning sites where accidents are common

Forum on Weathering Steel for Highway Structures: Summary Report

DTFJ61-88-R-00079On July 12-13, 1988 the Office of Research, Development and Technology of the Federal Highway Administration hosted a forum on Weathering Steel for Highway Structures. This conference took place at the Ramada Hotel in Alexandria, Virginia. The major objectives of this forum were to examine the state of the art in weathering steel use and maintenance, to develop rules for its use in new construction, and for maintenance of existing structures. The forum brought together 131 participants representing Federal and State governments and industry. The forum was organized into four main sessions, including a panel discussion and several individual presentations. The report summarizes the forum

One Basin at a Time: The Global Environment Facility and Governance of Transboundary Waters

Increased international attention to water resource management and integration has resulted in the creation of new institutional arrangements and environmental funding mechanisms. The Global Environmental Facility's (GEF) International Waters Program is at the heart of such novel collaborative approaches to managing transboundary resources. This paper assesses GEF-led efforts in twenty-three projects across ten geographic regions. It finds that the GEF has been successful in building scientific knowledge and creating linkages across social, economic and environmental issues. However, challenges of enhancing the contractual environment and building national capacity remain. While GEF efforts thus far do indicate that institutions can affect the growth of knowledge and cooperation around transboundary waters, long-lasting achievements of the GEF's International Waters Program have yet to be realized. Copyright (c) 2004 Massachusetts Institute of Technology.