Rami Harb

Two Simplified Intelligent Transportation System-Based Lane Management Strategies for Short-Term Work Zones

Intelligent transportation systems–based lane management technologies were introduced to work zones in an attempt to reduce congestion and diminish queue lengths. Two forms of lane merging—the early merge and the late merge—were designed to advise drivers on definite merging locations. This study suggests two SDLMS—early merge and late merge—to supplement the current Florida Maintenance of Traffic (MOT) plans. Data were collected in work zones on I-95, Florida using three different traffic maintenance treatments. The first MOT plan treatment was the standard MOT used by the Florida Department of Transportation. The second MOT plan was the early SDLMS, and the third MOT was the late SDLMS. Results showed that the maximum queue discharge rate (or capacity) of the work zone was significantly higher for the early SDLMS compared to the conventional Florida Department of Transportation MOT plans. The late SDLMS did not result in significant increase in the work zone capacity. Moreover, results showed that early merging rate was the highest for the early SDLMS and the lowest for the late SDLMS, which suggests that some drivers were complying with the messages displayed by the system.

Empirical Analysis of Toll-Lane Processing Times Using Proportional Odds Augmented MARS

A large deal of research has been conducted on toll roads to better comprehend the characteristics of the tolling operations. Several researchers indicated that toll-lane processing time (or service time) is the most significant key parameter in calibrating simulated toll plazas and one of the central variables affecting toll-lane capacity. This paper analyzes the effects of various factors on toll-lane processing times including traffic characteristics, vehicle characteristics, and toll plaza characteristics. The proportional odds augmented multivariate adaptive regression splines (MARS) model outperformed the proportional odds model and was used as the final model in interpreting the results. Results indicate that plazas charging higher tolls and plazas requiring drivers to pay with inexact bills have larger processing times. Increased demand and increased interarrival times at the toll plazas outermost right lane also have higher processing times. Finally, results indicate that processing times during the p.m. peak hour are higher than the a.m. peak hour.

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

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.

Comparing Three Lane Merging Schemes for Short-Term Work Zones: A Simulation Study

Traffic safety and mobility of roadway work zones have been considered to be one of the major concerns in highway traffic safety and operations in Florida. Dynamic lane merging (DLM) systems—ITS-based lane management technology—were introduced by several states in an attempt to enhance both safety and mobility of roadway work zones. Two forms of lane merging, namely, the early merge and the late merge were designed to advise drivers on definite merging locations. Up to date, there are no studies that contrast both merging schemes under matching work zone settings. This study simulates a two-to-one work zone lane closure configuration under three different Maintenance of Traffic (MOT) plans in VISSIM. The first MOT is the conventional plans used in Florida’s work zones, the second MOT is a simplified dynamic early merging system (early SDLMS), and the third MOT is a simplified dynamic late merging systems (late SDLMSs). Field data was collected to calibrate and validate the simulation models. Simulation results indicated that overall, under different levels of drivers’ compliance rate and different percentages of trucks in the traffic composition, the early SLDMS outperformed the conventional MOT and the late SDLMS in terms of travel times and throughputs.

UCF Driving Simulator’s Research and Application in Traffic Safety and Operation

The University of Central Florida (UCF) driving simulator housed in the Center for Advanced Transportation Systems Simulation is an I-Sim Mark-III system with a high driving fidelity and immense virtual environments. The UCF driving simulator provides a research platform for multi-disciplinary investigations in the traffic engineering area. This paper describes several simulator studies that aimed at enhancing the quality of traffic safety and operation, including measuring drivers’ minimum gap acceptance at stop-controlled intersections, analyzing the effects of dynamic sight distance problem on traffic safety, evaluating a pavement marking countermeasure for reducing red-light running, and assessing the safety benefits of variable speed limits.