Research Idea Details

Research Idea Scope

With the rapid development of new energy passenger vehicles and high speed rail, heavy duty trucks will likely become the major greenhouse gas (GHG) emission contributor in transportation sector. In the U.S., the majority of commodities are transported by heavy duty trucks through complex logistics network systems. A typical logistics network consists of ports, highway networks and distribution centers. Any changes in this network, such as improvements to roads or construction of a new corridor or distribution center, will affect the performance of the logistics system and have corresponding environmental impacts. An environmental impact analysis method which provides quick and accurate emission estimation in response to any changes in the logistic system will be very helpful to government agencies which conduct social-economic evaluation during infrastructure development planning.

This research focuses on proposing and testing a framework that integrates a freight transport modeler and a vehicle emission simulator to evaluate the emission of heavy duty trucks within the logistic network by studying operational behaviors. Multiple scenario studies and sensitivity analyses will be readily accomplished by altering initial inputs (such as network structure, freight demand, and the type or volume of commodities shipped). The proposed framework includes two concurrent studies:1) Freight flow analysis in a logistics network, 2) Truck driver behavior within logistics model.

Traditional environmental analyses of truck logistics systems focus on technological performance studies, estimating emissions using estimations of integrated tonnage flow and total travel distance. These methods cannot estimate changes in truck emissions resulting from alterations in the logistic network. Additionally, without a better understanding of driver behaviors in the logistic network, including actions such as speed changes and the number of start/stop times within the transportation process, the accuracy of quantitative environment impact studies is very limited. The integrated framework proposed in this study can overcome the above disadvantages utilizing the embedded logistics model which generates accurate analyses using four key factors aspects impacting heavy trucks emissions:

1. Network characteristics, such as road class and level of service.
2. Number and location of distribution centers. For instance, excessive local distribution center density may lead to inefficient route planning and frequent starts and stops, contributing to greater total emissions.
3. The freight demand. The demand directly affects the total tonnage flow throughout the network.  
4. Network changes. A new highway corridor or a new distribution center might completely change the freight flow mode.

This study utilizes Motor Vehicle Emission Simulator (MOVES) developed by Environmental Protection Association (EPA) which estimates emissions from heavy duty trucks covering a broad range of pollutants and allows multiple scale analysis. Analysis Data from a logistics transportation model, including the network structure, flow and routes of commodities, the number of truckloads on each link, and the travel distance for each truckload will serve as input to MOVES to obtain consequent environmental impact. The transportation model can process the scenarios analysis very quickly and also provide input to MOVES for rapid sensitive analysis.  Research output will be a comprehensive and flexible emission analysis of heavy duty vehicles traveling in a specific logistic network.  By combining a freight flow model with passenger model, the additional travel time resulting from congested traffic can be accurately estimated and included in environmental studies.

Project completion requires expertise from both freight modeling and transportation environment impacts study areas. Currently, a novel logistics and freight transportation model is under construction. The analysis range currently focus on regional networks, but is readily expandable to statewide nationwide studies. This framework can help the environmental impact analysis of freight logistic system, and related infrastructure development in a scientific and accurate way.

Urgency and Payoff

1. An integrated framework including freight transport modeler and a vehicle emission simulator to evaluate the emission of heavy duty trucks within the logistic network by studying operational behaviors
2. An accurate emission estimation of heavy duty trucks in response to any changes in the logistic system, which can assist government agencies conduct social-economic evaluation during infrastructure development planning.
3. A combined regional traffic model considering both freight and passenger flows to provide accurate estimation of traffic conditions, and included in environmental studies.