Table of Contents
ISRN Civil Engineering
Volume 2012, Article ID 435618, 9 pages
Research Article

Evaluating Variable Speed Limits and Dynamic Lane Merging Systems in Work Zones: A Simulation Study

1Planning Wing, National Highway Authority, Islamabad 44000, Pakistan
2CATSS, Department of Civil and Environmental Engineering, University of Central Florida, Orlando, FL 32816, USA

Received 29 February 2012; Accepted 1 May 2012

Academic Editors: P. J. S. Cruz and I. Raftoyiannis

Copyright © 2012 Zaier Zaidi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


ITS technologies such as dynamic lane merging (DLM) and variable speed limits (VSL) have been deployed in roadway work zones in an attempt to enhance safety and mobility through vehicular traffic. The DLM system in its two main forms namely the early merge and the late merge was designed to advise drivers on definite merging locations whereas VSL were introduced to work zones to decrease speed fluctuations, variances, and to smoothen traffic through work zones. Up to date, there are no studies that contrast Maintenance Of Traffic (MOTs) plans including a combination of ITS technologies to standard work zones MOTs under matching work zone settings. This study simulates a two-to-one work zone lane closure configuration in VISSIM under six different MOT plans and compares work zone throughputs and travel times across MOTs namely Motorist Awareness System (MAS), early DLM, late DLM, VSL combined with MAS, a VSL and early DLM combination, and a VSL late DLM combination. Results showed that the combination of VSL and DLM or standalone DLM improve work zone throughputs and travel times compared to work zones with conventional static Florida MOT and work zones with VSL.