Traffic Operations and Management

A Theory of Traffic Flow in Automated Highway Systems

Broucke, M.
Varaiya, P.
1995

This paper presents a theory for automated traffic flow, based on abstraction of vehicle activities such as entry, exit and cruising, derived from a vehicle's automatic control laws. The theory formulates TMC traffic plans as the specification of the activities and speed of vehicles, and the entry and exit flows for each highway section. The theory permits the study of transient phenomena such as congestion, and TMC feed back traffic rules designed to deal with transients.

A Simulation-Based Framework for the Analysis of Traffic Networks Operating with Real-time Information

Jayakrishnan, R.
Cohen, Michael
Kim, John
Mahmassani, Hani S.
Hu, Ta-yin
1993

The focus of this research project was to develop a new simulation framework for analyzing traffic networks with Advanced Traveler Information Systems (ATIS) and/or Advanced Traffic Management Systems ( ATMS). The report describes the development of DYNASMART (DYnamic Network Assignment-Simulation Model for Advanced Road Telematics). The report is presented as follows: Chapter 1 discusses the simulation approach of DYNASMART and explains the traffic control features incorporated in it during the research. Chapter 2 discuss the simulations performed with a trial network with ATMS controls....

A Functional Architecture for Automated Highway Traffic Planning

Tsao, H. S. Jacob
1994

This report defines an architecture for Automated Highway System (AHS) capacity-optimizing traffic planning functions. It identifies major traffic planning functions useful for optimizing the capacity of one or more major AHS operating scenarios and organizes them in a robust architecture that is modular, hierarchical, complete, expandable and integratable.

Vehicle-Based Control Computer Systems

Auslander, David M
1995

This report is presented in two parts: the first part describes a design and implementation methodology for real time software suitable for control of mechanical systems such as vehicles. This method provides for a design description of the system, a means of capturing the system structure in such a way as to modularize the software writing job, and a portable implementation method. The second part is concerned with a particular problem in the mechanical system control: estimating velocity when the even rate from a digital encoder is lower than the controller's sample time. Methods are...

Unintended Environmental Impacts of Nighttime Freight Logistics Activities

Sathaye, Nakul
Harley, Robert
Madanat, Samer
2009

In recent years, the reduction of freight vehicle trips during peak hours has been a common policy goal. To this end, policies have been implemented to shift logistics operations to nighttime hours. The purpose of such policies has generally been to mitigate congestion and environmental impacts. However, the atmospheric boundary layer is generally more stable during the night than the day. Consequently, shifting logistics operations to the night may increase 24‐hour average concentrations of diesel exhaust pollutants in many locations. This paper presents realistic scenarios for two...

System Optimum and Pricing for the Day-Long Commute with Distributed Demand, Autos and Transit

Daganzo, Carlos F.
2013

The day-long system optimum (SO) commute for an urban area served by auto and transit is modeled as an auto bottleneck with a capacitated transit bypass. A public agency manages the system’s capacities optimally. Commuters are identical except for the times at which they wish to complete their morning trips and start their evening trips, which are given by an arbitrary joint distribution. They value unpunctuality – their lateness or earliness relative to their wish times – with a common penalty function. They must use the same mode for both trips. Commuters are assigned personalized mode...

Synergies of Combining Demand and Supply-Side Measures to Manage Congested Streets

Itani, Ibrahim
Cassidy, Michael J.
Daganzo, Carlos
2021

An agent-based, multichannel simulation of a downtown area reveals the impacts of both time-shifting traffic demand with congestion pricing, and supplying extra capacity by banning left turns. The downtown street network was idealized, and loosely resembles central Los Angeles. On the demand-side, prices were set based on time-of-day and distance traveled. On the supply side, left-turn maneuvers were prohibited at all intersections on the network. Although both traffic management measures reduced travel costs when used alone, the left-turn ban was much less effective than pricing. When...

SPRINTER Rail: Grade Crossing/Traffic Signal Optimization Study

Wu, Guoyuan
Li, Irene
Zhang, Wei-Bin
Johnston, Scott
Li, Meng
Zhou, Kun
2009

The second phase of this project further investigates impacts to local traffic operations at intersections adjacent to signal preemption by SPRINTER commuter trains and comes up with countermeasures that not only minimize such impacts but also take into account the traffic signal coordination. An extended traffic signal optimization model has been developed to minimize overall traffic delays and the weighted width of “green band” along several coordinated traffic signals around the grade crossings. Based on the train’s movement detection at grade crossings and the waiting queue estimation...

Some Traffic Features at Freeway Bottlenecks

Cassidy, Michael J.
Bertini, Robert L.
1999

Observations from two freeway bottlenecks in and near Toronto, Canada indicate that the average rate vehicles discharge from a queue can be 10% lower than the flow measured prior to the queue's formation. Absent any influences from downstream, the queue discharge flows exhibited nearly stationary patterns that alternated between higher and lower rates. These alternating flow patterns were especially evident at one of the two sites, although the feature occurred at both sites during periods that immediately followed the onset of upstream queueing; i.e. a queue's formation was always...

PATH ATMIS State of the Research Annual Report Fiscal Year 1998/1999

Tam, Robert
1999

This report summarizes PATH ATMIS and Systems research for fiscal year 1998/1999. In each of the brief project descriptions we state the objectives of the project and outline its status and some of its principal results. These descriptions are not intended to be comprehensive or complete, but rather to present a picture of the main thrusts of each of the reported projects. References are provided in the end of the report for more detailed information about particular projects. Taken together, the collection of project descriptions should also give a reader an overview of the entire program...