2013 Session: 832

• Chemical Reaction Optimization Approach to Solving the Environmentally Sustainable Network Design Problem
  Abstract: Nowadays the decision makers in transportation industry are being urged to instill environmental values into road network design decision-making. To evaluate a road network design, not only should it be cost-effective, but also sustainable. This article proposes a new methodology to consider all the environmental concerns into a network design problem (NDP). This proposed NDP is formulated as a bi-level program. The lower level problem is formulated as static UE-assignment model. In the upper level, total emission costs and noise costs are calculated as monetary terms into the objective function value and minimized with the total system travel time cost at the same time. It is known that such bi-level problem is NP-hard, a new metaheuristic called the Chemical Reaction Optimization (CRO) method is implemented to solve it. This newly invented algorithm has been proved to have a wide application field and satisfying performance compared with other metaheuristics. Two benchmark city road networks with different scales are used to evaluate the performance of CRO. This study also addresses the importance of incorporating the environmental concerns into NDP sufficiently and the tradeoffs between different objective components are explored. It is found that CRO outperforms Genetic Algorithm (GA) on certain scenarios and have an overall comparable performance compared with GA.
  Authors: Szeto, Wai Yuen; Wang, Yi; Wong, S. C.
  Authors: Szeto, Wai Yuen; Wang, Yi; Wong, S. C.
  Year: 2013
  Document Type: Paper
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-1619
• On the Existence of the Simultaneous Occurrence of Braess and Emission Paradoxes
  Abstract: Braess¡¦ paradox is well-known and examined. However, an emission paradox, an analogue to Braess¡¦ paradox for vehicular emissions, is not. Without considering the emission paradox, the road network improvement that mitigates congestion may increase harmful vehicular emissions. In this paper, we analytically examine the occurrence of the emission paradox and the simultaneous occurrence of the Braess and emission paradoxes in the classical Braess¡¦ network. We ascertain that the occurrence of the emission paradox depends on the demand for travel, the parameters of link performance functions as well as link emission factors. We also find that the Braess and emission paradoxes do not always occur at the same time, and that the emission paradox is more likely to occur than the Braess paradox in some networks. More importantly, we discover that under some conditions of the parameters of link performance functions, the emission paradox does occur but Braess¡¦ paradox does not. This implies that road network design for mitigating congestion alone may not be able to avoid the increase in vehicular emissions. A more comprehensive view for road network design is necessary to avoid the occurrence of both the Braess and emission paradoxes.
  Authors: Szeto, Wai Yuen; Jaber, Xiaoqing; O'Mahony, Margaret
  Authors: Szeto, Wai Yuen; Jaber, Xiaoqing; O'Mahony, Margaret
  Year: 2013
  Document Type: Paper
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-1745
• Differentiated Congestion Pricing of Urban Transportation Networks with Vehicle-Tracking Technologies
  Abstract: This paper explores a new type of congestion pricing that differentiates users with respect to their travel characteristics and charges them different amount of toll accordingly. The scheme can reduce the financial burden of travelers or lead to more substantial reduction of congestion. Given that the scheme requires tracking vehicles, an incentive program is designed to mitigate travelers' privacy concerns and entice them to voluntarily disclose their private travel information.
  Authors: Zangui, Mahmood; Yin, Yafeng; Lawphongpanich, Siriphong; Chen, Shigang
  Authors: Zangui, Mahmood; Yin, Yafeng; Lawphongpanich, Siriphong; Chen, Shigang
  Year: 2013
  Document Type: Paper
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-1825
• Analysis and Design of Tradeable Credit Schemes Under Uncertainty
  Abstract: Market-based instruments for congestion mitigation can be generally classified into two classes, i.e., price- and quantity-based. The former, widely-known as congestion pricing, charges tolls to influence travelers’ decisions, while the latter regulates quantity directly. More specifically, credits or permits are first distributed by a government agency, and travelers are then required to pay a certain number of credits to access transportation facilities. The credits can be traded among travelers and the price is determined by the market through free trading. In this paper we formally establish the identity between congestion pricing and tradable credit schemes in managing network mobility. Using a numerical example, we demonstrate how the identity falls apart when there is uncertainty associated with transportation supply or demand. We then conduct sensitivity analysis of the coupled network and market equilibrium to predict how credit price varies with respect to the perturbation associated with the supply or demand. A safety valve policy is then investigated to balance regulation success and price volatility under uncertainty.
  Authors: Shirmohammadi, Nima; Zangui, Mahmood; Yin, Yafeng; Nie, Yu
  Authors: Shirmohammadi, Nima; Zangui, Mahmood; Yin, Yafeng; Nie, Yu
  Year: 2013
  Document Type: Paper
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-1826
• Integrated Pricing of Roads and Electricity Enabled by Wireless Power Transfer
  Abstract: This paper explores integrated pricing of electricity and roads enabled by wireless power transfer technology. We envision that high-power, high-efficient wireless power transfer technologies are mature in the near future, which electrify roads to be charging infrastructures. The prices of electricity at electrified roads will affect electric vehicles’ route choices while the energy requirement of those vehicles will in return affect the operations of the power network and thus the prices of electricity. To determine the optimal prices of electricity and roads to maximize social welfare, first- and second-best pricing models are proposed under different authoritarian regimes. More specifically, assuming that a government agency manages both transportation and power systems, we develop the first-best pricing model, based on which a marginal-cost pricing scheme is derived. The second-best pricing model is proposed if the agency participates in a competitive wholesale power market while being able to impose tolls on electrified roads. The toll design is formulated as a mathematical program with complementarity constraints, and is solved by a manifold suboptimization algorithm. Numerical examples are presented to offer insights on integrated pricing of roads and electricity and demonstrate its effectiveness on improving social welfare.
  Authors: He, Fang; Yin, Yafeng
  Authors: He, Fang; Yin, Yafeng
  Year: 2013
  Document Type: Paper
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-1822
• Optimizing Variable Speed Limits for Efficient, Safe, and Sustainable Mobility
  Abstract: This paper envisions a variable speed limit system where speed limits vary strategically and periodically in accordance with traffic and weather conditions to achieve better safety, efficiency and environment sustainability on a traffic network. For such a variable speed limit system, we propose a tri-objective bi-level programming model to design optimal link-specific speed limits that minimize system travel time, number of expected accidents and traffic exhaust emissions simultaneously for each specific strategic scenario. A solution framework is developed to solve the model, which implements a non-dominated sorting genetic algorithm and integrates various tools for performance evaluation. The proposed model and solution framework are demonstrated using the road network within the 2nd ring road in Beijing.
  Authors: Yang, Yanni; Lu, Huapu; Yin, Yafeng; Yang, Hai
  Authors: Yang, Yanni; Lu, Huapu; Yin, Yafeng; Yang, Hai
  Year: 2013
  Document Type: Paper
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-1828
• Unconstrained Formulation of Environmentally Constrained Traffic Equilibrium Problem
  Abstract: Various government legislations have recently been issued to alleviate the environmental deterioration of transportation systems. Environmental constraint is a valid means to explicitly reflect various environmental protection requirements imposed by the government. In this paper, we examine the environmentally constrained traffic equilibrium problem (EC-TEP), which is a fundamental tool for modeling and evaluating environmental protection requirements. Specifically, we provide an equivalent reformulation for the EC-TEP. The proposed reformulation adapts the concept of gap function to simultaneously reformulate the nonlinear complementarity conditions associated with the generalized user equilibrium conditions, environmental constraints, and conservation constraints as an equivalent unconstrained optimization problem. This gap function reformulation has two desirable features: (1) it can handle a general environmental constraint structure (linear or nonlinear; link-based or area-based) and a general link and route cost structure, enhancing the modeling adaptability and flexibility; (2) it is smooth and unconstrained, permitting a number of existing efficient algorithms for its solution. A gradient-based solution algorithm with a self-regulated averaging stepsize scheme is customized to solve the reformulated unconstrained optimization problem. Numerical examples are also provided to demonstrate the modeling flexibility of the proposed EC-TEP reformulation.
  Authors: Xu, Xiangdong; Chen, Anthony; Cheng, Lin
  Authors: Xu, Xiangdong; Chen, Anthony; Cheng, Lin
  Year: 2013
  Document Type: Paper
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-2086
• Taxis in Road-Pricing Zone: Should They Pay the Congestion Charge?
  Abstract: This paper investigates the problem of whether taxis should be tolled in the pricing zone when designing congestion pricing scheme. A bi-level programming model is developed to compare the maximum social welfares before and after the congestion charge is imposed on taxis. The lower-level is a combined network equilibrium model (CNEM) formulated as a variational inequality program, which considers the logit-based mode split, route choice, elastic demand and vacant taxi distributions. The upper-level is to maximize the social welfare when toll rates vary. The bi-level problem can be solved by a conventional Genetic Algorithm, whereas the lower-level is solved by the block Gauss-Seidel decomposition approach together with the method of successive averages and diagonalization algorithm. A numerical example is conducted to demonstrate the effectiveness of the proposed model and algorithm and to promote some interesting findings.
  Authors: Zhu, Jincheng; Xiao, Feng
  Authors: Zhu, Jincheng; Xiao, Feng
  Year: 2013
  Document Type: Paper
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-2470
• Network Flows of Plug-In Electric Vehicles: Impacts of Electricity-Charging Price
  Abstract: This paper is intended to model and evaluate the impacts of electricity-charging prices on work-related commuting network flows of electric vehicles. A stochastic user-equilibrium network flow problem is formulated and analyzed for commuters who drive battery electric vehicles and incorporate charging costs into routing decision makings. Given the spatial difference of electricity-charging prices, solving the problem requires tracking all individual paths. As such, a path-based solution algorithm based on the disaggregated simplicial decomposition scheme, with some modifications in the path generation phase and an added k-shortest path search procedure for eliminating the solution inaccuracy issue, is proposed for problem solutions. We implemented the modeling and solution methods for evaluating the network performance changes caused by varying electricity-charging prices in multiple network-level and link-level evaluation matrices. The evaluation results show that the traffic network of battery electric vehicles incurs a higher vehicle miles traveled (VMT) value and a lower vehicle hours traveled (VHT) value compared to the network of gasoline vehicles, and the VMT value decreases and the VHT value increases with the increase of either the origin-based or destination-based electricity-charging price.
  Authors: Zhang, Ti; Xie, Chi; Waller, S. Travis
  Authors: Zhang, Ti; Xie, Chi; Waller, S. Travis
  Year: 2013
  Document Type: Paper
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-2611
• Model-Based Dynamic Pricing Algorithm for Managed Lanes
  Abstract: Managed lanes, or high occupancy toll (HOT) lanes have been implemented across US to improve the utility of existing road facilities. The pricing algorithm in managed lanes is the critical component in making sure that the desired level of service metrics is met. Some pricing algorithms currently in use are static algorithms, while others adopt a dynamic strategy. Static pricing algorithms do not account for the changes in real time traffic conditions. On the other hand, dynamic pricing algorithms are reactive in nature, and do not account for the potential demand for actual future time interval that the toll is determined for. HOT system is nonlinear and complex in nature leading to high levels of instability in such a system. This complexity has been increasing due to the growth in demand as well as incorporation of non-interacting other strategies that are implemented to address this demand. Hence, more sophisticated designs of the pricing algorithm are needed for HOT pricing control. A model-based pricing algorithm is proposed for determining toll rate dynamically to maximize the throughput on the HOT lanes while maintaining desired level of service (LOS). It consists of both proactive and reactive components to achieve fast response to real-time changes and maintain a steady, maximal traffic flow. The controller structure also incorporates active bottleneck management to maintain optimal traffic flow under stressed conditions. Implementation of this controller has led to higher average HOT throughput. Also, the results are less sensitive to the variation in the traffic flow and driver behavior as compared to a typical feedback based pricing algorithm.
  Authors: Fu, Lina; Kulkarni, Rakesh
  Authors: Fu, Lina; Kulkarni, Rakesh
  Year: 2013
  Document Type: Paper
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-2911
• Computing and Evaluating Equilibrium Network Flows of Gasoline and Electric Vehicles
  Abstract: This paper addresses a simple traffic assignment problem with mode and route choices for the emerging need of modeling traffic networks that accommodate electric vehicles. Two transportation modes (or vehicle types), gasoline and electric vehicles, are exclusively included in the problem, which distinguish from each other in terms of the driving distance limit and travel cost composition. A convex programming model is proposed as a modeling tool for evaluating such mixed-mode traffic networks that are anticipated to exist for a long period in the electrified transportation era. Our focus in this paper is on the computation and evaluation of this mixed-mode traffic assignment problem’s solutions. In particular, we developed and implemented two competitive solution algorithms: one is a linear approximation algorithm of the Frank-Wolfe type, which allows for a parallel treatment of O-D pairs and a one-to-all constrained shortest path procedure for path generation; another is a quadratic approximation algorithm that makes use of the Gauss-Seidel decomposition to deal with O-D pairs in a sequential manner and generate paths by a one-to-one constrained shortest path procedure. Our experimental results from applying these algorithms for a number of synthetic and realistic networks clearly show that, from the model behavior perspective, the produced mode-route flows replicate the anticipated travel choice pattern, and, from the solution efficiency perspective, the relative competitiveness of the two algorithms depends on the required solution precision.
  Authors: Jiang, Nan; Xie, Chi
  Authors: Jiang, Nan; Xie, Chi
  Year: 2013
  Document Type: Paper
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-4251
• Combined Distribution and Stochastic Assignment Problem with Distance Constraint
  Abstract: This paper formulates a combined distribution and stochastic assignment model for destination and route choice with two classes of vehicles: gas and pure electric. Pure electric vehicles are subject to distance constraints representing range limitations, while gas vehicles have no such constraints. For both types of trips, the travel demand will be allocated to destinations and paths according to the principles of logit-based distribution and stochastic user equilibrium. In particular, we derive the equivalency of the model results and the allocation principle. An algorithm for the solution of the model is developed. Finally, several numerical studies are implemented which show the impacts of distance constraints on distribution and assignment.
  Authors: Tang, Shoupeng; Boyles, Stephen; Jiang, Nan
  Authors: Tang, Shoupeng; Boyles, Stephen; Jiang, Nan
  Year: 2013
  Document Type: Paper
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-4476
• On the Existence of the Simultaneous Occurrence of Braess and Emission Paradoxes
  Authors: Szeto, Wai Yuen
  Authors: Szeto, Wai Yuen
  Year: 2013
  Document Type: Presentation
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-1745
• Chemical Reaction Optimization Approach to Solving the Environmentally Sustainable Network Design Problem
  Authors: Wang, Yi
  Authors: Wang, Yi
  Year: 2013
  Document Type: Presentation
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-1619
• Optimizing Variable Speed Limits for Efficient, Safe, and Sustainable Mobility
  Authors: Yang, Yanni
  Authors: Yang, Yanni
  Year: 2013
  Document Type: Presentation
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-1828
• Integrated Pricing of Roads and Electricity Enabled by Wireless Power Transfer
  Authors: He, Fang
  Authors: He, Fang
  Year: 2013
  Document Type: Presentation
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-1822
• Analysis and Design of Tradeable Credit Schemes Under Uncertainty
  Authors: Shirmohammadi, Nima
  Authors: Shirmohammadi, Nima
  Year: 2013
  Document Type: Presentation
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-1826
• Unconstrained Formulation of Environmentally Constrained Traffic Equilibrium Problem
  Authors: Chen, Anthony
  Authors: Chen, Anthony
  Year: 2013
  Document Type: Presentation
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-2086
• Differentiated Congestion Pricing of Urban Transportation Networks with Vehicle-Tracking Technologies
  Authors: Zangui, Mahmood
  Authors: Zangui, Mahmood
  Year: 2013
  Document Type: Presentation
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-1825
• Computing and Evaluating Equilibrium Network Flows of Gasoline and Electric Vehicles
  Authors: Jiang, Nan
  Authors: Jiang, Nan
  Year: 2013
  Document Type: Presentation
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-4251
• Network Flows of Plug-In Electric Vehicles: Impacts of Electricity-Charging Price
  Authors: Zhang, Ti
  Authors: Zhang, Ti
  Year: 2013
  Document Type: Presentation
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-2611
• Model-Based Dynamic Pricing Algorithm for Managed Lanes
  Authors: Fu, Lina
  Authors: Fu, Lina
  Year: 2013
  Document Type: Presentation
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-2911
• Combined Distribution and Stochastic Assignment Problem with Distance Constraint
  Authors: Tang, Shoupeng
  Authors: Tang, Shoupeng
  Year: 2013
  Document Type: Presentation
  Subject: Energy; Planning and Forecasting
  Session: 832
  Paper Number: 13-4476