PATH

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...

New Approach to Bottleneck Capacity Analysis: Final Report

Banks, James H.
2006

A capacity analysis approach intended as an alternative to the traditional Highway Capacity Manual (HCM) method was evaluated. One- and two-stage models of pre-queue and queue discharge flow (each of which might be thought of as representing “capacity” in some sense) were developed and compared with one another and the HCM method. Two-stage models related capacity flows to intervening variables, including average time gaps (average time separations between the rear of a vehicle and the front of one following it) in the critical lane (that with the highest flow rate) and the critical lane...

Transient Aerodynamic Effects on a Four-Car Platoon During Passing Maneuvers: Data Summary

Tsuei, L.
Hedrick, J. K.
Savas, O.
1999

In order to provide reliable control algorithms on PATH automated highway system, knowledge of the transient aerodynamic forces is important from the point of the controlla- bility of the platoon and individual vehicles. In a passing maneuver, the platoon members may experience severe aerodynamic forces and yaw moment when another vehicle overtakes. Similar phenomenon can be seen in our daily life as one car passes the other but much more complicated flow field is expected when the interaction involves in a multi-vehicle platoon. It is the purpose of this study to quantify the unsteady...

Safety Performance and Robustness of Heavy Vehicle AVCS

Taylor, R. Jemonde
Yih, Paul
Gerdes, J. Christen
2005

Dynamically, heavy trucks are inherently different than passenger cars. In addition to the increase rollover risk arising from an elevated center of gravity height, heavy trucks possess additional failure modes such as jackknifing and excessive trailer swing. As a response to these issues, significant research has been performed in the last three decades to establish safety metrics for heavy trucks based on dynamic testing. This research has had an impact on determining acceptable size and weight restrictions for heavy vehicles and on the actual design of heavy trucks for increased safety...

Safety Performance and Robustness of Heavy Vehicle AVCS

Yih, Paul
Satyan, Krishna
Gerdes, J. Christian
2003

Commercial heavy vehicle research at the California Partners for Advanced Transit and Highways (PATH) program has focused on the development of controllers for partially to fully automated driving environments. Safe performance of Advanced Vehicle Control Systems (AVCS) must be demonstrated for a wide range of operating conditions and truck configurations to avoid any one of the many failure modes-such as rollover or jackknifing-common to articulated heavy vehicles. For this purpose, a multi-body dynamic model of a tractor semitrailer has been developed using a commercially available...

A Futures Market for Demand Responsive Travel Pricing

June 25, 2024

Authors: Nicholas Fournier, Ph.D., Postdoctoral Researcher, SafeTREC, PATH, University of California, Berkeley; Anthony Patire, Ph.D., Research & Development Engineer, PATH, University of California, Berkeley; and Alexander Skabardonis, Ph.D., Professor, Department of Civil & Environmental Engineering, University of California, Berkeley.

Abstract:

Dynamic toll pricing based on demand can increase transportation revenue while also incentivizing travelers to avoid peak traffic periods. However, given the unpredictable nature of...

Evaluating the Costs and Benefits of Transit Smart Cards

Iseki, Hiroyuki, PhD
Demisch, Alexander
Taylor, Brian D., PhD
Yoh, Allison C., MA
2008

Smart cards are gaining momentum as transit agencies across the country have been implementing them as a fare medium. Smart cards hold the promise of revolutionizing the way riders use transit, and how transit systems operate. But in order to adopt smart cards, transit agencies must purchase new equipment and upgrade their entire fare collection system – a very expensive process. In addition, many of the oft-touted benefits of smart cards are vague, and it is not at all certain if they are worth the high cost of implementation.This study examines how transportation agencies in three...

GPS/GIS Technologies for Traffic Surveillance and Management: A Testbed Implementation Study

McNally, M.G.
Marca, J.E.
Rindt, C.R.
Koos, A.M.
2002

The fundamental principle of intelligent transportation systems is to match the complexity of travel demands with advanced supply-side analysis, evaluation, management, and control strategies. A fundamental limitation is the lack of basic knowledge of travel demands at the network level. Modeling and sensor technology is primarily limited to aggregate parameters or micro-simulations based on aggregate distributions of behavior. Global Positioning Systems (GPS) are one of several available technologies which allow individual vehicle trajectories to be recorded and analyzed. Potential...

Rest Areas – Reducing Accidents Involving Driver Fatigue

Banerjee, Ipsita
Lee, Joon ho
Jang, Kitae
Pande, Swati
Ragland, David
2010

Rest areas are a countermeasure for fatigue; what role do they play in fatigue-related freeway collisions? The present study spatially evaluates fatigue collisions. In California, of 2,203,789 highway collisions recorded between 1995 and 2005, fatigue collisions accounted for 1.3% (‘strict’ definition of fatigue) and 9.7% (‘expanded’ definition). Collisions in the vicinity of rest areas were investigated using two different approaches: 1. 10-miles up/downstream of rest areas 2. Distance traveled from rest areasSample t-tests indicated that both fatigue and non-fatigue collisions decreased...

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...