01626520

Component

Evaluation of the adequacy of sight distance at roundabout is currently performed graphically as no quantitative guidelines are available for the lateral clearance needs. This paper presents analytical lateral clearance models to satisfy stopping sight distance at single-lane symmetrical roundabouts. The models are developed for three locations: approach sight distance, exit sight distance, and circulatory roadway sight distance. Two cases of approach sight distance are presented: sight distance to the crosswalk and sight distance to the yield line. Design aids for the required maximum lateral clearance are established for the three locations of sight distances using the analytical models. The required lateral clearance at any specified point along the curve can also be determined. For the circulatory roadway sight distance, infeasible combinations of the circulatory roadway radius and speed are identified based on the adequate driver’s field of vision. The models and results of this paper could be integrated in existing roundabout software to automate the evaluation of sight distance.

This paper was sponsored by TRB committee AFB10 Standing Committee on Geometric Design. Alternate title: Lateral Clearance Needs for Stopping Sight Distance at Single-Lane Roundabouts.

01618707

17-06289

English

17p

2017

Transportation Research Board 96th Annual Meeting

Digital/other

Figures; References; Tables

Clearances (Navigation); Crosswalks; Evaluation and assessment; Geometric design; Roundabouts; Sight distance; Yielding

Design; Highways; Operations and Traffic Management

Transportation Research Board Annual Meeting 2017 Paper #17-06289

TRIS, TRB, ATRI

Dec 8 2016 12:33PM