Optimization of fuel cell/battery hybrid vehicle systems has primarily focused on reducing fuel consumption. However, it is also necessary to focus on fuel cell and battery durability as inadequate lifespan is still a major barrier to the commercialization of fuel cell vehicles. Here, we introduce a power management strategy which concurrently accounts for fuel consumption as well as fuel cell and battery degradation. Fuel cell degradation is quantified using a simplified electrochemical model which provides an analytical solution for the decay of the electrochemical surface area (ECSA) in...
The size of the individual powerplant components on board a fuel cell/battery hybrid vehicle affects the power management strategy which determines both the fuel economy and the durability of the fuel cell and the battery, and thus the average lifetime cost of the vehicle. Cost is one of the major barriers to the commercialization of fuel cell vehicles, therefore it is important to study how the sizing configuration affects overall vehicle cost. In this paper, degradation models for the fuel cell and the battery on board a fuel cell/battery hybrid bus are incorporated into the power...
Signal equipment upgrades (e.g., multiple timing plan capability and/or signal interconnection) are commonly used to improve the quality of traffic flow in urban arterials and networks. These signal control improvements generally result in considerable delay, stops and fuel savings but the benefits vary widely on different networks. Procedures are needed to provide guidance on the benefits likely to be achieved from improving signal hardware. This report discusses the major factors that influence signal equipment performance and presents the findings of the assessment of the impacts from...
This paper describes the activities in developing and applying improved computer techniques in traffic signal management, performed in the technical center established at the Institute of Transportation Studies (ITS), as part of the Fuel Efficient Traffic Signal Management (FETSIM) project. The center provides technical support to local agencies, develops software and conducts research for most efficient use of the state of the art computer programs. A description of the available programs is given and how these tools can be used in the various phases of a signal retiming study. Selected...
This report presents the findings from the evaluation of a statewide initiative to retime traffic signals to produce more energy-efficient traffic flow: California's FuelEfficient Traffic Signal Management (FETSIM) Program. During the 11 years of the Program, over 160 cities and counties have retimed a total of 12,245 signals under grants from the FETSIM Program, in 334 projects. Improved timings have reduced vehicular delays by 14 percent in project areas; stops have been decre~sed by 13 percent. Overall travel times through these systems have dropped by 7 percent and fuel consumption has...
The Fuel-Efficient Traffic Signal Management (FETSIM) Program was initiated in 1982 to help local agencies retime their traffic signals to reduce stops, delays, and fuel consumption. This report presents the results of the fourth and fifth grant cycles of the FETSIM Program. During the two grant cycles, local agency staff and their consultants were provided training, technical assistance and funding necessary to optimize the timing of their signal systems and to put the new timing plans into operation. In the 1986 grant cycle, thirty-one local agencies retimed 1169 signals at a total cost...
Need to develop theory, tools, and methods that allow for self-consistent and transparent comparisons of promising alternative energy and vehicle pathways (hydrogen, biofuels, electricity, and fossil fuels). Also, to inform the public debate and to assist our public and private sponsors on sustainable transportation alternatives.
The Freeway Service Patrol (FSP) program has the goal of reducing congestion by using fleets of roving tow and service trucks to quickly clear disabled vehicles and address other minor accidents on California’s freeway. The FSP program is jointly managed by Caltrans, the California Highway Patrol (CHP), and regional transportation agencies. Approximately $21.25 million in State transportation funds are provided each year to eligible regional transportation agencies for the FSP program using a formula-based allocation. The Road Repair and Accountability Act of 2017 (SB 1) directs an...
This chapter presents the results of experiments on coordinated automatic longitudinal control of a platoon of three Class 8 tractor-trailer trucks, using 5.9 GHz DSRC with 100 ms update intervals for coordination. The trucks were tested not only in constant-speed cruising conditions, but also through acceleration and deceleration profiles, up and down grades, and in platoon join and split maneuvers using the DSRC coordination. These tests showed good vehicle following accuracy, ride quality and platoon stability. The desired gaps between the trucks were varied between 10 and 4 m to...
Quantifying the effect of Cooperative Adaptive Cruise Control (CACC) on traffic mobility and vehicle fuel consumption has been a challenge because it requires a modeling framework that depicts the interactions among manually driven vehicles and CACC vehicles in the complex multilane traffic stream. This study adopted a state-of-the-art traffic flow modeling framework to explore the impacts of CACC on vehicle fuel efficiency in mixed traffic. The analyses at a freeway merge bottleneck indicated that the CACC string operation resulted in a maximum of 20% reduction in energy consumption...
