Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/25881
Title: TRAFFIC DELAY ESTIMATION,OPERATIONAL STRATEGY ANALYSIS AND RISK ASSESSMENT FOR WORK ZONES.
Authors: WENG JINXIAN
Keywords: Work Zone, Traffic Delay, Work Zone Capacity, Work Zone Cost, Operational Strategy Analysis, Risk Assessment
Issue Date: 5-Sep-2011
Source: WENG JINXIAN (2011-09-05). TRAFFIC DELAY ESTIMATION,OPERATIONAL STRATEGY ANALYSIS AND RISK ASSESSMENT FOR WORK ZONES.. ScholarBank@NUS Repository.
Abstract: Work zone projects are necessary for maintaining a good level of service for a road system. In addition to the work zone costs for contractors of completing a work zone project, a work zone project also results in long travel delays and high accident risk for road users. It is thus important to estimate traffic delay, analyze the work zone operational strategy and assess the accident risk for work zone projects. This thesis aims to develop the proper methodologies/models to deal with these three practical issues. The thesis first builds a novel heterogeneous cellular automata (HCA) model to estimate work zone traffic delays. Compared to the existing cellular automata models, the HCA model possesses three unique characteristics - improved forwarding rules to characterize longitudinal vehicular movements, improved lane changing rules to describe lateral vehicular movements, and randomization probability functions. A case study shows that the HCA model is able to estimate work zone traffic delay more precisely than the other models. This thesis then proposes a decision tree-based model to estimate work zone capacity, which is a key factor in measuring traffic delays at work zones. The statistical comparison results demonstrate that the proposed decision tree-based work zone capacity estimation model outperforms the existing work zone capacity models. To analyze the work zone operational strategy, this thesis develops two minimization models and solution algorithms for the optimal subwork zone operational strategy. The first model comes from the system optimum viewpoint, with the objective of minimizing total work zone cost by taking into account variable traffic speeds and the constraint that each subwork zone has uniform length. A genetic simulated annealing method is employed to solve this model. The second model aims to minimize the maintenance costs concerned by the contactors, subject to the queue length and travel delay constraints. A trial-and-error solution method with practical implications is designed. Numerical examples are employed to assess the proposed minimization models and the corresponding solution methods. The last part of this thesis is concerned with the work zone risk assessment. It first presents a new approach for estimating the rear-end crash risk at work zones by using real work zone traffic data. A probabilistic quantitative risk assessment (QRA) model is subsequently put forward to quantitatively estimate the vehicle occupant¿s casualty risk. This model consists of a crash frequency estimation function, an event tree and a consequence estimation model, in which some input parameters are assumed to be random variables to reflect their uncertainty. This thesis provides a useful guideline which traffic engineers can use to estimate work zone delays and capacities, find an optimal subwork zone operational strategy and assess work zone risk.
URI: http://scholarbank.nus.edu.sg/handle/10635/25881
Appears in Collections:Ph.D Theses (Open)

Show full item record
Files in This Item:
File Description SizeFormatAccess SettingsVersion 
WengJX.pdf2.16 MBAdobe PDF

OPEN

NoneView/Download

Page view(s)

369
checked on Dec 11, 2017

Download(s)

30
checked on Dec 11, 2017

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.