Roads/Highways

Parameter Estimation and Command Modification for Longitudinal Control of Heavy Vehicles

Bae, Hong S.
Gerdes, J. Christian
2003

Commercial heavy vehicles, unlike passenger vehicles, display huge variation in parameters such as vehicle mass. Coupled with lower actuation authorities (engine and brake capabilities), these variations can induce actuator saturation even in moderately demanding maneuvers, presenting challenge to the task of maintaining string stability in a platoon formation of heavy trucks. A new control scheme is proposed to put on-line bounds, or artificial saturation, on command signals via parameter estimation such that all members in a platoon can follow the reference commands without saturating...

Seamless Travel: Measuring Bicycle and Pedestrian Activity in San Diego County and its Relationship to Land Use, Transportation, Safety, and Facility Type

Jones, Michael G.
Ryan, Sherry
Donlon, Jennifer
Ledbetter, Lauren
Ragland, David R.
Arnold, Lindsay
2010

This paper provides the data collection and research results for the Seamless Travel project. The Seamless Travel Project is a research project funded by Caltrans and managed by the University of California Traffic Safety Center, with David Ragland, PhD., as the Principal Investigator and Michael Jones as the Project Manager. The project is funded by Caltrans Division of Innovation and Research and is being conducted by the Traffic Safety Center of University of California Berkeley and Alta Planning + Design.Measuring bicycle and pedestrian activity is a key element to achieving the goals...

A Simple Time Sequential Procedure For Predicting Freeway Incident Duration

Khattak, Asad J.
Schofer, Joseph L.
Wang, Mu-han
1994

The objective of this study is to develop a methodology for incident duration prediction. The authors first developed an understanding of factors that influence incident duration. A series of truncated regression models is used to predict incident duration. The models account for the fact that incident information at a Traffic Operations Center is acquired over the life of the incident. The implications of this simple methodology for incident duration prediction are discussed.

Estimating ATIS Benefits For The Smart Corridor

Sengupta, Raja
Hongola, Bruce
1998

This report studies the effects of Advanced Traveler Information Systems (ATIS) on traffic congestion in the Smart Corridor of the Santa Monica Freeway. Simulation modeling is used to estimate the potential travel time savings to divert traffic from the Smart Corridor to arterial roads when incidents occur. The study attempts to establish relationships between traffic management variables, such as incident detection time, incident duration, capacity reduction, percentage of traffic diversion, and duration of traffic diversion.

A Comparative Systems-level Analysis: Automated Freeways, Hov Lanes, Transit Expansion, Pricing Policies And Land Use Intensification

Johnston, Robert
1997

The focus of this project was to examine the potential travel, emissions, and consumer benefits of advanced freeway automation and travel demand management measures. The Sacramento Regional Travel Demand model (SACMET 95) was used to simulate the travel effects of travel demand management measures in the Sacramento region for a twenty year time horizon. The scenarios examined included various combinations of automated freeways, new High Occupancy Vehicle (HOV) lanes, transit, land use intensification, and pricing policies.

Address Resolution in One Lane Automated Highway Systems

Bana, Soheila V.
Varaiya, Pravin
1999

Address Resolution Protocols (ARP) are used in Automated Highway Systems (AHS) to establish communication among vehicles. The purpose of the ARP is to determine the network address of neighboring vehicles. We are proposing an innovative solution that takes advantage of the automated road infrastructure. For providing addresses initially and uses the communication network itself for updating the network communication addresses in a one lane automated highway system. The protocol has been modeled using PROMELA [1], and simulated and verified by SPIN [2]. SPIN is a tool for analyzing the...

Freeway Performance Measurement System (PeMS)

Chen, Chao
2003

The freeway Performance Measurement System (PeMS) collects real time traffic data from sensors and generates performance measures of vehicle miles traveled, hours traveled, and travel time. This project is sponsored by the California Department of Transportation (Caltrans). PeMS provides tools and reports for traffic planners, operators, and engineers. It has a Web interface. Growing traffic demand in metropolitan areas has far outpaced increases in freeway lane-miles in the United States. The solution to congestion lies in increasing the efficiency of existing infrastructure. Performance...

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...