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Unformatted text preview: ive Percentage Values used for Normal Distribution in OU Fitting Distribution Comparison Graph (Figure 9 c, d) ........................................................ 41 Table 13: Cumulative Percentage Values used for Pearson Type III Distribution in OU Fitting Distribution Comparison Graph (Figure 9 e, f) ............................................. 43 Table 14: Percentages of Passenger Cars and Trucks for Driving Lane and Passing Lane according to OU Video Record................................................................................. 58 xii Table 15: Vehicle Speeds used for the Transporters in the ARENA Simulation Model.. 61 Table 16: Minimum Safe Space for Lane Changing before the Lane Closure Taper (adapted from Kanaris et al. [32]) ............................................................................. 66 Table 17: Required Gaps for Lane Changing Maneuver Derived from Van Aerde Car Following Model (adapted from Rakha and Crowther [33]) .................................... 69 Table 18: Required Space for Lane Changing when the Merging Vehicle Speed is Greater or equal than the Desired Lane Speed....................................................................... 71 Table 19: Required Space for Lane Changing when the Merging Vehicle Speed is less than the Desired Lane Speed..................................................................................... 72 Table 20: Required Space for Lane Changing when there are Less than 3 Vehicles waiting in the Queue at the Lane Closure Taper....................................................... 73 Table 21: Required Space for Lane Changing when there are Less than 5 Vehicles waiting in the Queue at the Lane Closure Taper....................................................... 74 Table 22: Required Space for Lane Changing when there are Less than 10 Vehicles waiting in the Queue at the Lane Closure Taper....................................................... 74 Table 23: Required Space for Lane Changing when there are More than 10 Vehicles waiting in the Queue at the Lane Closure Taper....................................................... 75 Table 24: Hourly Vehicle Counts and Hourly Demand Factors for 08/20/2004 .............. 94 Table 25: Output Summary Table ..................................................................................... 97 Table 26: Comparison of Number of Vehicles observed in the Field during Data Collection and the Number of Vehicles Obtained from Simulation Output........... 100 1 1 INTRODUCTION A simulation study is concerned with the building of a model for a problem rather than directly working with the problem itself. Successful simulation study needs comprehensive and multidisciplinary knowledge and experience [1]. The main purpose of a traffic simulation model in construction zones is to estimate the delay times for the drivers and determine bottlenecks, which cause delays for the drivers. Reduced guidance, dense traffic, merges at lane reductions and entrance ramps are the main causes of traffic delays in construction work zones. Traffic simulation models are used to replicate the operations of actual traffic systems. These simulation models are very powerful tools to predict the characteristics of traffic flow in different conditions. Accurately modeling the traffic in work zones will prevent the bottlenecks in the work zones, and it will reduce the delay times. Traffic simulation models are divided into two main categories: microscopic simulation models and macroscopic simulation models [2]. Microscopic models simulate the traffic flow by using the behavior of the individual vehicles or characteristics of the drivers. Microscopic models help us to predict the actual traffic flow better than the macroscopic models. In microscopic models, car following behavior, lane-changing behavior, acceleration and deceleration behaviors are included in the model individually. On the other hand, macroscopic traffic simulation models regard traffic flow as a continuum or as a stream of fluid. Traffic modeling is basically a queueing system. Queueing situation always will occur when a service facility is not capable to serve all the arrivals at some point in time. In traffic simulation, vehicles entering the system are the entities arriving and the road 2 section is the service facility, which has a service distribution related with the speeds of the incoming vehicles. The inter-arrival time probability density func tion can be determined by measuring the exact times that the vehicles enter the work zone. The service time probability density function can be determined using the speed profile of the vehicles in the work zone and delays associated with the merger and constricted lanes. There are basically two types of queueing models; deterministic and probabilistic models [3]. In deterministic models there are no probability distributions associated with the arrival of events or service times. The arrivals of events with the constant rate are known. Howe...
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This document was uploaded on 02/26/2014 for the course E 515 at University of Louisiana at Lafayette.

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