Relationship between Design, Operating, and Posted Speeds under High-Posted SpeedConditions

摘要

The overall objective of this research was to investigate the relationshipbetween design, operating and posted speed on rural two-lane two-way highways in Nebraska with posted speeds of 55, 60, and 65. Crest vertical curvature and horizontal curvature on a sample of these existing highways in Nebraska were investigated to determine if changes in vertical and horizontal alignments affected the operating speeds of motorists using the roadway. Procedures were suggested to help determine: a reasonable design speed to use on a new or reconstructed highway; a reasonable initial posted speed on a new or reconstructed highway; and a reasonable posted speed for an existing highway.