Modeling

Asymptotic Approximations for the Transportation LP and Other Scalable Network Problems

Carlos Daganzo
Smilowitz, Karen R.
2000

Network optimization problems with a "scalable" structure are examined in this report. Scalable networks are embedded in a normed space and must belong to a closed family under certain transformations of size (number of nodes) and scale (dimension of the norm.) The transportation problem of linear programming (TLP) with randomly distributed points and random demands, the earthwork minimization problem of highway design, and the distribution of currents in an electric grid are examples of scalable network problems. Asymptotic formulas for the optimum cost are developed for the case where...

Urban Gridlock: Macroscopic Modeling and Mitigation Approaches

Carlos Daganzo
2007

This paper describes an adaptive control approach to improve urban mobility and relieve congestion. The basic idea consists in monitoring and controlling aggregate vehicular accumulations at the neighborhood level. To do this, physical models of the gridlock phenomenon are presented both for single neighborhoods and for systems of inter-connected neighborhoods. The models are dynamic, aggregate and only require observable inputs. The latter can be obtained in real-time if the neighborhoods are properly instrumented. Therefore, the models can be used for adaptive control. Experiments should...

The Potential of Parsimonious Models for Understanding Large Scale Transportation Systems and Answering Big Picture Questions

Carlos Daganzo
Gayah, Vikash V.
Gonzales, Eric J.
2012

A model with few variables is said to be parsimonious. If it is also analytically tractable, physically realistic, and conceptually insightful, it is said to be effective. Effective parsimonious models have long been used in fields such as economics and applied physics to describe the aggregate behavior of systems as opposed to the behavior of their individual parts. In transportation, these models are particularly well suited to address big picture questions because they provide insights that might be lost when focusing on details. This paper presents an abbreviated history of effective...

Introduction: Control Problems for Conservation Laws with Traffic Applications

Bayen, Alexandre
Maria Laura Delle Monache
Garavello, Mauro
Goatin, Paola
Piccoli, Benedetto
Alexandre Bayen
2022

This book focuses on control problems for conservation laws, i.e., equations of the type: ∂tu+∂xf(u)=0ut+(f(u))x=0,$$\displaystyle \partial _t\, u + \partial _x\, f(u) = 0 \qquad u_t+(f(u))_x=0, $$where u:ℝ+×ℝ→ℝn$$u:\mathbb {R}^+\times \mathbb {R} \to \mathbb {R}^n$$is the vector of conserved quantities and f:ℝn→ℝn$$f:\mathbb {R}^n\to \mathbb {R}^n$$is the flux. Most results will be given for the scalar case (n = 1), but we will present few results valid in the general case.

Distributed Control for Conservation Laws

Alexandre Bayen
Maria Laura Delle Monache
Garavello, Mauro
Goatin, Paola
Piccoli, Benedetto
2022

This chapter focuses on control of systems of conservation laws with distributed parameters. Problem with different parameterized fluxes is addressed: in particular, we deal with cases where the control is the maximal speed and look for continuous dependence of the solution on parameters.

Boundary Control of Conservation Laws Exhibiting Shocks

Alexandre Bayen
Maria Laura Delle Monache
Garavello, Mauro
Goatin, Paola
Piccoli, Benedetto
2022

This chapter focuses on control of systems of conservation laws with boundary data. Problems with one or two boundaries are considered and, in particular, we focus on cases where shocks may be developed by the solution. However, for completeness we briefly discuss in Sect. 2.2 other existing results where singularities are prevented via suitable feedback controls such as in [32].

Decentralized Control of Conservation Laws on Graphs

Alexandre Bayen
Maria Laura Delle Monache
Garavello, Mauro
Goatin, Paola
Piccoli, Benedetto
2022

Conservation and/or balance laws on networks in the recent years have been the subject of intense study, since a wide range of different applications in real life can be covered by such a research.

Nonlinear Advection-Diffusion Models of Traffic Flow: a Numerical Study

Matin, Hossein Nick Zinat
Do, Dawson
Maria Laura Delle Monache
2023

The first-order degenerate parabolic traffic flow dynamics are the simplest extension of the Lighthill, Whitham, and Richards (LWR) model which aim at correcting the discrepancies between the LWR model and the observation collected from real data. In addition, the nonlinearity and degeneracy of these models are designed to address the fundamental criticism of linear diffusivelycorrected kinematic-wave models. While several first-order methods have been proposed in the literature, the predictive capabilities of these models has not been sufficiently studied with respect to real data. The...

Control Problems for Hamilton-Jacobi Equations Co-authored by Alexander Keimer

Alexandre Bayen
Maria Laura Delle Monache
Garavello, Mauro
Goatin, Paola
Piccoli, Benedetto
2022

In this chapter, we introduce Hamilton-Jacobi PDEs. These PDEs are related to conservation laws and their solutions are the anti-derivative (in space) of the Entropy solutions of the corresponding conservation law, given that some assumptions are satisfied.

Near Collision and Controllability Analysis of Nonlinear Optimal Velocity Follow-the-Leader Dynamical Model In Traffic Flow

Matin, Hossein Nick Zinat
Maria Laura Delle Monache
2023

This paper examines the optimal velocity follow-the-leader dynamics, a microscopic traffic model, and explores different aspects of the dynamical model, with particular emphasis on collision analysis. More precisely, we present a rigorous boundary-layer analysis of the model which provides a careful understanding of the behavior of the dynamics in trade-off with the singularity of the model at collision.