Environment

Field Experiments Demonstrate Fuel Savings for Close-Following

Michaelian, Mark
Browand, Fred
2000

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...

EPTT-2018-0047 Recirculating Large-Scale Structures Inside the Cove of a Sealed Slat

Himeno, FHT
Amaral, FR
Souza, DS
Rodriguez, D
Medeiros, MAF
2018

The development on Environmental Regulations related to aircraft noise propagated to the vicinity of airports forced the industry to investigate the noise sources and look for alternatives of noise reduction. The current aircraft noise has a large contribution provenient from the airframe, due to the turbofan engine development. One can identify the most relevant sources as the landing gear, flap and slat. Since slat is distributed in almost whole extension it becomes a distributed noise source. The presence of excrescences inside slat cove can changes significantly the recirculating flow...

Evaluation of the ACC Vehicles in Mixed Traffic: Lane Change Effects and Sensitivity Analysis

Ioannou, Petros
Stefanovic, Margareta
2003

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...

Development of a Heavy-Duty Diesel Modal Emissions and Fuel Consumption Model

Barth, Matthew
Younglove, Theodore
Scora, George
2005

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...

Integrating a Comprehensive Modal Emissions Model into ATMIS Transportation Modeling Frameworks

Barth, Matthew
Malcom, Carrie
Scora, George
2001

Intelligent Transportation Systems (ITS) have generated considerable enthusiasm in the transportation community as a potential means to improve roadway safety, reduce congestion, enhance the mobility of people and goods, and reduce energy consumption and vehicle emissions. In order to estimate these potential benefits, new and improved analytical techniques and simulation models are being developed for ITS. In terms of environmental effects, the University of California, Riverside, College of Engineering-Center for Environmental Research and Technology (CE-CERT) has developed a...

Commercial Vehicle Parking in California: Exploratory Evaluation of the Problem and Solutions

Rodier, Caroline J., PhD
Shaheen, Susan A., PhD
Allen, Denise M.
Dix, Brenda
2010

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...

Commercial Motor Vehicle Inspection and Screening Stations: Evaluating Performance from the Perspective of Practitioners

Miller, Mark A.
Garefalakis, Antonios
2009

This report presents the findings of a study of commercial motor vehicle inspection and screening station practices with a focus on the use of various technologies to help address problems related to safety, security, roadway infrastructure, and air quality. A review of industry literature identified the various types of inspection and screening practices that have been and are being implemented including weight and size management, on-board equipment checking, driver-related violations and cargo monitoring, credential checking, and exhaust emissions monitoring. The review also identified...

Evaluation of Traffic and Environment Effects on Skid Resistance and Safety Performance of Rubberized Open-grade Asphalt Concrete

Oh, Soon Mi
Ragland, David R.
Chan, Ching-Yao
2010

Wet pavement-related collisions represent a significant traffic safety concern, due in part to the lack of adequate friction between tire and pavement, known as skid resistance. State agencies employ a skid number (SN) system, based on a standard test procedure in which a locked wheel is towed at 40 mph and the skid number (SN40) is calculated from the measured resistance. SN40 is used as a reference value for speeds both greater than and less than 40 mph. For most Departments of Transportation (DOTs) in the nation, excluding California, pavements for which the SN40 is below 30 are deemed...

Development of the Capability-Enhanced PARAMICS Simulation Environment

Chu, Lianyu
Liu, Henry
McNally, Michael
Recker, Will
2005

This report summarizes research work conducted under TO4304 at the University of California, Irvine. Under this task order, the research team provided Caltrans with on-call direct support, technical guidance, and research related support. A series of Paramics plug-ins were developed and have been released to Caltrans. These plug-ins include actuated signal, multiple actuated signal timing plan, actuated signal coordination, detector data aggregator, ramp metering control, on-ramp queue override control, ALINEA ramp metering control, BOTTLENECK ramp metering control, SWARM Ramp metering...

Evaluation of Incorporating Hybrid Vehicle Use of HOV Lanes

Brownstone, David
Chu, Lianyu
Golob, Tom
Nesamani, K.S.
Recker, Will
2008

This report presents a method to investigate the operational and environmental effects of the policy of allowing qualified single-occupancy hybrid vehicles to use dedicated High-Occupancy Vehicle (HOV)/carpool lanes in California.. The method combines the traditional planning method with microscopic simulation modeling. The planning method is used for demand estimation and analysis and the microscopic traffic simulation modeling method is used for accurate measures of the system. The study employs a microscopic traffic simulation model that is capable of evaluating the HOV/hybrid system...