working paper

Estimation of Automobile Emissions and Control Strategies in India

Publication Date

December 31, 2008

Abstract

Rapid, but unplanned urban development and the consequent urban sprawl coupled with economic growth have aggravated auto dependency in India over the last two decades. This has resulted in congestion and pollution in cities. The central and state Governments have taken many ameliorative measures to reduce vehicular emissions. However, evolution of scientific methods for accurate emission inventory is crucial. Therefore, an attempt has been made to estimate the emissions (running and start) from on-road vehicles in Chennai using IVE model in this paper. GPS was used to collect driving patterns.

The estimated emissions from motor vehicles in Chennai in 2005 were 431, 119, 46, 6 and 4575 tons/days respectively for CO, VOC, NOx, PM and CO2. It is observed from the results that air quality in Chennai has degraded. The estimation revealed that two and three-wheelers emitted about 64 percent of the total CO emissions and heavy-duty vehicles accounted for more than 60 percent and 36 percent of the NOx and PM emissions respectively. About 19 percent of total emissions were that of start emissions. The estimated health damage cost of automobile emissions in Chennai is Rs. 6488.16 million (US$162.20 million). This paper has further examined various mitigation options to reduce vehicular emissions. The Study has concluded that advanced vehicular technology and augmentation of public transit would have significant impact on reducing vehicular emissions.

research report

CARTESIUS and CTNET Integration and Field Operational Test: Year 1

Abstract

This report describes the results of PATH Task Order 5324—the first year of a multi-year project to integrate the Cartesius incident management system with Cal-trans CTNET traffic signal management system. The results of this research are a set of software requirements for reimplementing the Cartesius to interoperate with CTNET. An analysis of the existing Cartesius prototype explains how the need to focus the system on deployment and technical shortcomings of the existing system justifies a reimplementation of the software. From here, we describe the problem to be solved by the new software implementation, including general use cases, the expected users, the systems that Cartesius will interoperate with, and the constraints that will be placed on the system. The problem statement is followed by a detailed discussion of the functional requirements, database requirements, the user interface requirements, and other external interface requirements. The report concludes with a discussion the reimplementation work to be completed under PATHTask Order 6324. This reimplementation will serve the more general purpose of making Cartesius capable of working with existing traffic management subsystems to provide multi-jurisdictional incident mitigation, thus improving its deployability and subsequent value for Caltrans.

research report

Integrated Ramp Metering Design and Evaluation Platform with Paramics

Abstract

California currently has three major ramp metering systems: 1) San Diego Ramp Metering System (SDRMS), 2) Semi-Actuated Traffic Management System (SATMS); and, 3) Traffic Operations System (TOS). This report describes a study which focused on developing a user-friendly Integrated Ramp Metering design and evaluation Platform (IRMP) that uses the Paramics simulator to provide a comprehensive set of performance measures for evaluation studies. The report first describes the framework of the IRMP. It next summarizes the detector placement in California for ramp metering applications. Following a detailed description of the SATMS, SDRMS, and TOS ramp metering systems, the report then summarizes and compares these existing ramp metering systems. Potential metering algorithms such as ALINEA and SWARM are also discussed. Finally, the report describes how to implement IRMP and includes the user manual for IRMP.

working paper

A Bid Analysis Model with Business Constraints for Transportation Procurement Auctions

Publication Date

November 30, 2008

Abstract

Business to business (B2B) auctions have become a dominant mechanism used by large shippers to procure contracts for transportation services from logistics companies. The bid analysis problem is of critical importance to shippers and determines which contracts are assigned to specific carriers and at what price. In practice this problem is further complicated by the consideration of shipper business rules, such as restrictions on carrier numbers, limits on the number of individual packages awarded and preferences for incumbent carriers. This paper examines the case in which bidding packages are mutually exclusive. This is referred to as a non-combinatorial auction. In practice, this type of auction is preferred to a full combinatorial auction because it allows the auctioneer (the shipper) to maintain control of the packages and creates much less cognitive strain for bidders (trucking companies). A mathematical programming model for the bid analysis problem is presented and heuristic construction algorithms and Lagrangian relaxation based algorithms are developed to solve the problem. Numerical results show that our Lagrangian relaxation based heuristics perform better than other heuristics and that the solutions are very close to optimal.

Phd Dissertation

Real option-based procurement for transportation services

Publication Date

November 30, 2008

Abstract

Uncertainty in transportation capacity and cost poses a significant challenge for both shippers and carriers in the trucking industry. In the practice of adopting lean and demand-responsive logistics systems, orders are required to be delivered rapidly, accurately and reliably, even under demand uncertainty. These tougher demands on the industry motivate the need to introduce new instruments to manage transportation service contracts. One way to hedge these uncertainties is to use concepts from the theory of Real Options to craft derivative contracts, which we call truckload options in this dissertation. In its simplest form, a truckload call (put) option gives its holder the right to buy (sell) truckload services on a specific route, at a predetermined price on a predetermined date. The holder decides if a truckload option should be exercised depending on information available when the option expires. Truckload options are not yet available, however, so the purpose of this dissertation is to develop a truckload options pricing model and to show the usefulness of truckload options to both shippers and carriers. Since the price of a truckload option depends on the spot price of a truckload move, we first model the dynamics of spot rates using a common stochastic process. Unlike financial markets where high frequency data are available, spot prices for trucking services are not public and we can only observe some monthly statistics. This complicates somewhat the estimation of necessary parameters, which we obtain via two independent methods (variogram analysis and maximum likelihood), before developing a truckload options pricing formula. Finally, a numerical illustration based on real data shows that truckload options would be quite valuable to the trucking industry. This dissertation develops a method to create value through more flexible procurement contracts, which could benefit the trucking industry as a whole-particularly in an uncertain business environment. Truckload rates and options prices are rigorously investigated and modeled. In addition, parameter estimation for a continuous stochastic model is explored using discrete statistics. Finally, numerical examples are illustrated and a picture of truckload option trading is presented. Results suggest that truckload options have the potential of significantly benefiting the trucking and logistics industries.

working paper

Development of Hardware in the Loop Simulation and Paramics/VS-PLUS Integration

Abstract

The report describes three research efforts carried out under a project titled “Development of Hardware-in-the-Loop (HiL) Simulation and Paramics/VS-PLUS Integration” sponsored by the California Department of Transportation (Caltrans) under Task Order 5311. The first effort developed and evaluated traffic signal optimization with Hardware-in-the-Loop Simulation (HiLS), using the NIATT Controller Interface Device (CID) manufactured by McCain Traffic Supply to provide real-time linkage between the Paramics microscopic simulation and a NEMA TS1 controller. An adaptive control system incorporated the traffic flow prediction model to predict the traffic flows from the surrounding intersections, and an online signal optimization model was used to obtain the signal timing plan for the subsequent cycle, based on the traffic flows predicted in the previous cycle. The performance of the proposed adaptive control system was evaluated through a case study in which HiLS is applied to a small urban network in Logan, Utah. The second effort developed a Paramics plug-in that worked over a serial port connection to a specially modified 170 for HiL operation. After this initial development, the NIATT/McCain CID was configured to work as a Paramics plug-in with both 170 and 2070 controllers, and experiments were carried out to compare the performance of Paramics simulations with the UC Irvine Paramics signal controller plug-in with HiLS. In the third effort, investigation and evaluation of integrated Paramics/VS-PLUS software was carried out, resulting in a user’s guide for use of the integrated Paramics/VS-PLUS simulation software.

working paper

A Statewide Optimal Resource Allocation Tool Using Geographic Information Systems, Spatial Analysis, and Regression Methods

Abstract

The overall objective of this project is to develop an optimal resource allocation tool for the entire state of California using Geographic Information Systems and widely available data sources. As this tool evolves it will be used to make investment decisions in transportation infrastructure while accounting for their spatial and social distribution of impacts. Tools of this type do not exist due to lack of suitable planning support tools, lack of efforts in assembling data and information from a variety of sources, and lack of coordination in assembling the data. Suitable planning support tools can be created with analytical experimentation to identify the best methods and the first steps are taken in this project. Assembly of widely available data is also demonstrated in this project. Coordination of fragmented jurisdictions remains an elusive task that is left outside the project. When this project begun we confronted some of these issues and embarked in a path of feasibility demonstration in the form of a pilot project that gave us very encouraging results. In spite of this pilot nature aiming at demonstration of technical feasibility, substantive conclusions and findings are also extracted from each analytical step.

In this project we have two parallel analytical tracks that are a statewide macroanalysis (called the zonal based approach herein) and an individual and household based microanalysis (called the person based approach herein). In the statewide macroanalysis we study efficiency and equity in resource allocation. Resources are intended as infrastructure availability and access to activity participation offered by the combined effect of transportation infrastructure and land use measured by indicators of accessibility. Stochastic frontiers are used to study efficiency and a particular type of inequality measurement called the Theil fractal inequality index is used to study equity in the macroanalysis. The outcome of this analysis are maps identifying places in California that enjoy higher levels of service when compared to the entire state and places which succeeded in allocating resources in a relatively better way than others. In the individual microanalysis we use the accessibility indicators from the macronalysis and expand them by defining a new set of indicators at a second level of spatial (dis)aggregation. Then we use them as explanatory factors of travel behavior with focus on the use of different travel models (e.g., driving alone, use of public transportation and so forth). As expected infrastructure availability and accessibility to activity opportunities has a significant and substantive effect on the use of different modes. Many resource allocation decisions, then, will impact behavior, which in turn influences the optimality and equity conditions. This implies that decisions about where and when to allocate resources in public and private transportation needs to account for changes in behavior in a dynamic fashion, using scenarios of accessibility provision and assessing their impact by studying activity and travel behavior changes.

Phd Dissertation

Operational Strategies for Single-Stage Crossdocks

Publication Date

October 27, 2008

Abstract

Because of the growing importance of hub-and-spoke operations in the trucking industry, crossdocking has become an important and effective tool to transfer freight. Companies like Wal-Mart, Costco and Home Depot are using this kind of facility in their logistics operations. In these crossdocks, efficiently operating them, thereby reducing unnecessary waiting and staging congestion for freight and workers is an important issue for managers.

This dissertation uses real-time information about the contents of inbound and outbound trailers and the locations of pallets to schedule unloading for waiting trailers or assign destinations for unloading pallets: we choose a waiting trailer that will need the least time for its pallets and existing pallets; and we may assign an alternate destination for a pallet if its primary destination is expected to encounter congestion. Two dynamic trailer scheduling and four alternate destination strategies are proposed and compared with baseline scenarios.

Our simulation results suggest that:

1. Our strategies are effective. The two time-based trailer scheduling algorithms can save cycle times as much as 64%, 57% and 30% in the 4-to-4, 4-to-8 and 8-to-8 crossdock scenarios, respectively; the four alternate destination strategies can save cycle times as much as 34% in the 8-to-8 staging crossdock scenarios. In addition, these strategies can raise throughputs for crossdocks. These effects should result in noticeable improvements in supply chain networks, including shorter transportation lead-times, more reliable on-time deliveries and lower inventory costs.

2. In our alternate destination strategies, even if a destination-change results in extra time for value-added services for freight, the strategies are still worth adopting.

3. The combination models of our trailer scheduling algorithms and alternate destination strategies work better than solely implementing an alternate destination strategy when trailer arrivals are dense.

4. A higher flexibility in choosing alternate destinations can bring higher performance for crossdocks.