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Title:

Reduction in Flow Due to U-Turns at Median Openings

Accession Number:

01630062

Record Type:

Component

Abstract:

The U-turns at median openings disturb the movement of approaching through traffic, which reduces the flow. Out of several available methods, N-curve technique is most widely used for capacity drop estimation. Because of assumed flow conservation, this method is inappropriate to use. Therefore, the present study proposes a new methodology for estimating reduction in flow of approaching through vehicles. The reduction is more prominent near the center of median opening and gradually decreases in the upstream direction. Field data were collected from seven median openings to identify the possible slowdown section. Number of vehicles crossing each segment (at regular interval of 10 m) at every 20 s were noted to calculate the reduction in flow. The reduction in flow, estimated at different segments of slow down section as well as at the centre of median opening by the proposed method, are compared to those obtained by N-curve method and no difference is observed. The reduction in flow at different lanes are also studied. Highest reduction in flow was observed in the lane adjacent to median whereas a gain in flow was noticed in lane adjacent to curb. An equation has been proposed for estimating reduction in flow at the centre of median opening based on the total number of U-turns exposed to approaching through traffic and total number of gradual merging. The equation is validated by comparing the values obtained from the equation with the values observed from field.

Supplemental Notes:

This paper was sponsored by TRB committee AHB40 Standing Committee on Highway Capacity and Quality of Service.

Monograph Accession #:

01618707

Report/Paper Numbers:

17-00195

Language:

English

Corporate Authors:

Transportation Research Board

500 Fifth Street, NW
Washington, DC 20001 United States

Authors:

Mohanty, Malaya
Dey, Partha Pratim
Mishra, Ambikeya

Pagination:

20p

Publication Date:

2017

Conference:

Transportation Research Board 96th Annual Meeting

Location: Washington DC, United States
Date: 2017-1-8 to 2017-1-12
Sponsors: Transportation Research Board

Media Type:

Digital/other

Features:

Figures; References; Tables

Subject Areas:

Highways; Operations and Traffic Management; Planning and Forecasting

Source Data:

Transportation Research Board Annual Meeting 2017 Paper #17-00195

Files:

TRIS, TRB, ATRI

Created Date:

Dec 8 2016 9:58AM