Environment

There are only two ways to increase the throughput of vehicles on a highway—either construct more freeway lanes, or accommodate a shortened average spacing between individual vehicles (while maintaining speed). Providing a rational means for close-following is an attempt to accomplish the latter. The maximum throughput for a typical freeway lane is about 2000 vehicles/hour, and is roughly independent of the attributes of any particular freeway. The number is remarkably inelastic varying little over the past twenty years in spite of great improvements in the design of freeways and in the...

Almost every automobile company is producing vehicles with Adaptive Cruise Control (ACC) systems that allow a vehicle to do automatic vehicle following in the same lane. The ACC system is designed for driver comfort and safety and to operate with manually driven vehicles. These characteristics of ACC were found to have beneficial effects on the environment and traffic flow characteristics [1, 2, 3] by acting as filters of a wide class of traffic disturbances. It has been argue that the smooth response of ACC vehicles to high acceleration disturbances or large position errors creates large...

There have been significant improvements in recent years in transportation and emissions modeling, in order to better evaluate transportation operational effects and associated vehicle emissions. In particular, instantaneous or modal emissions models have been developed for a variety of light-duty vehicles. To date, most effort has focused primarily on developing these models for light-duty vehicles with less effort devoted to Heavy-Duty Diesel (HDD) vehicles. Although HDD vehicles currently make up only a fraction of the total vehicle population, they are major contributors to the...

California is home to major international ports in Long Beach, Los Angeles, and Oakland, as well as the second largest border crossing between Mexico and the U.S. California’s highways are critical commercial links from these ports of entry to the nation and carry more commercial vehicle truck traffic than any other state in the U.S. Given the high volume of truck travel in California, it is not surprising that there is a serious shortage of truck parking in the state. This shortage negatively impacts economic productivity, roadway safety, air quality, and public health. This report begins...