01349746

Component

http://www.trb.org/Publications/Blurbs/165662.aspx

This chapter presents a literature review of operating speed models developed in North America. Several geometric design variables appear to be associated with operating speeds along rural highways and urban streets in North America. The following relationships appear to converge for studies reported along low-speed urban streets: the presence of a median is associated with higher operating speeds; operating speeds decrease as the degree of horizontal curve increases; operating speeds decrease as the roadside becomes more restricted (i.e., objects closer to roadway); operating speeds decrease as the vertical grade increases; operating speeds decrease as the access density increases; and the presence of parking and sidewalks are associated with lower operating speeds. The following relationships have been reported for geometric variables and operating speeds along rural multilane highways: free-flow operating speeds decrease as the access density increases; the presence of a paved shoulder is associated with higher operating speeds; increasing the vertical grade is associated with lower operating speeds; and increasing the length or radius of horizontal curve is associated with higher operating speeds. Concerning the relationship between geometric variables and operating speeds along suburban highways, the following relationships have been reported: operating speeds increase as the available sight distance increases;operating speeds decrease as the access density increases; operating speeds decrease as the roadside becomes more restricted (i.e., objects closer to roadway); the presence of a paved shoulder is associated with higher operating speeds; increasing the radius of horizontal curve is associated with higher operating speeds; increasing the deflection angle of the horizontal curve is associated with lower operating speeds; and increasing the curvature change rate or ratio of successive horizontal curves is associated with lower operating speeds.

01349742

English

pp 3-42

2011-7

Transportation Research Circular

Web

Figures (1) ; Tables (20)

Access; Geometric design; Highway design; Literature reviews; Mathematical models; Operating speed; Paved shoulders; Roadside structures; Rural highways; Suburbs; Urban highways

Horizontal curvature; Speed prediction models; Suburban highways; Vertical grade

North America

Design; Highways; I20: Design and Planning of Transport Infrastructure

TRIS, TRB

Aug 15 2011 1:34PM

• Modeling Operating Speed: Synthesis Report. Chapter 1: Introduction
• Modeling Operating Speed: Synthesis Report. Chapter 3: Speed Models in Europe
• Modeling Operating Speed: Synthesis Report. Chapter 4: Speed Models in Other Regions and Road Types
• Modeling Operating Speed: Synthesis Report. Chapter 5: Deficiencies in Existing Speed Models
• Modeling Operating Speed: Synthesis Report. Chapter 6: Practitioners' Perspective
• Modeling Operating Speed: Synthesis Report. Chapter 7: Conclusions and Recommendations