01514496

Component

https://doi.org/10.3141/2436-06

AASHTO’s Policy on Geometric Design of Highways and Streets contains geometric design criteria for horizontal curves for new and major reconstruction. These criteria are based on design side friction factors that were established in the 1940s. The objective of this research was to establish a probabilistic approach to the design of horizontal curves and compare the results with current design criteria. Reliability analysis commonly is used in structural engineering and recently has been used in stopping sight distance research for transportation design. In this research, design variables were considered random instead of deterministic to incorporate variations that occurred in the field (e.g., driver heterogeneity or differences in tire performance characteristics) into the analysis. The effects of wet pavements and tire characteristics for passenger cars and heavy trucks were considered. The superelevation rate was considered as a design input, and minimum radii for a target reliability index were presented for combinations of input mean speeds and superelevation rates. All other design inputs were considered random variables (e.g., available pavement friction), along with their appropriate distributions, in the reliability analysis. The results show that a target reliability index of 3.0 is appropriate for use in the probabilistic design of horizontal curves. Furthermore, when only skidding failure is considered, the design criteria for passenger cars can reasonably accommodate heavy trucks. The recommendations for future research consider probabilistic methods and more complex models of horizontal curve forces.

01550529

14-1786

English

pp 51–59

2014

Transportation Research Record: Journal of the Transportation Research Board

9780309295345

Print

Figures (5) ; References (28) ; Tables (4)

Geometric design; Highway curves; Highway design; Radius; Superelevation; Tires; Wet weather

Probabilistic design; Reliability analysis; Reliability index

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

TRIS, TRB, ATRI

Jan 27 2014 2:38PM

• Application of Conflict Scoping Process to Transportation Projects
• Assessing Suitability of Nontraditional Development in Roadside Right-of-Way
• Crossover Roundabouts: An Alternative Interchange Design
• Effects of Geometric and Traffic Variables on Double Left-Turn Lane Operations
• Geometric and Operational Improvements at Continuous Flow Intersections to Enhance Pedestrian Safety
• Horizontal Clearance Offsets to Objects Higher Than Sight Lines
• Model of Flow Regimes in Porous Pavement and Porous Friction Courses
• Reliability-Based Geometric Design Approach for Selecting Basic Number of Freeway Lanes
• Removal of Dissolved Heavy Metals in Highway Runoff
• Safety Effects of Using Short Left-Turn Lanes at Unsignalized Median Openings
• Stochastic Empirical Loading and Dilution Model for Analysis of Flows, Concentrations, and Loads of Highway Runoff Constituents
• Stopping Sight Distance and Horizontal Sight Line Offsets at Horizontal Curves
• Strategies to Optimize the Management of Right-of-Way Parcel and Utility Information
• Superelevation Design for Sharp Horizontal Curves on Steep Grades
• Wave-Induced Scour at Cylindrical Piles: Estimating Equilibrium Scour Depth in a Transition Zone