Modeling

Brake System Modeling and Control

Hedrick, J. K.
Uchanski, M.
2001

MOU308 provides solutions to two common brake control problems: variable brake torque gain and brake rotor-induced brake torque oscillations. The adaptive control solution for the variable brake torque gain problem is shown to work experimentally, and the algorithm to eliminate brake torque oscillations is demonstrated in simulation. In addition, documentation is provided for differential braking hardware, wheel speed measurement hardware, and a strain-based brake torque sensor that were constructed to test these algorithms.

A Vehicle Collision Model for Platoon Controller Development

Tongue, Benson H.
Packard, Andrew
Harriman, Douglas
1997

This is the final report of the research program “Compatibility of Vehicles Within a Platoon (MOU-156).” This research area is continuing under a different, contract and thus, although the work presented herein is complete unto itself, the overall research goals laid out at the beginning of the program will not be attained until the conclusion of the entire related research effort.The material presented in this report provides a description of a simple dynamical model that can be used for determining the physical interaction of vehicles in a collision scenario. Such a model is of use in...

Dynamic Modeling and Simulation of Snowplow: Normal Operation and Icepack Impacts

Shou, Kun
Tomizuka, Masayoshi
Zhang, Wei-Bin
2000

Keywords: Dynamic Modeling, Snowplows, Multi-Unit Vehicles, Icepack Impacts, Braking Control, Steering Control.

Built Environment Profiles for Latin American Urban Settings: The SALURBAL Study

Sarmiento, OL
Useche, A
Rodriguez, DA
Dronova, I
Guaje, O
Montes, F
Stankov, I
Wilches, M
Bilal, U
Wang, X
Guzman, L
Pena, F
Quistberg, D
Guerra-Gomez, J
Roux, AV Diez
2021

The built environment of cities is complex and influences social and environmental determinants of health. In this study we, 1) identified city profiles based on the built landscape and street design characteristics of cities in Latin America and 2) evaluated the associations of city profiles with social determinants of health and air pollution. Landscape and street design profiles of 370 cities were identified using finite mixture modeling. For landscape, we measured fragmentation, isolation, and shape. For street design, we measured street connectivity, street length, and directness. We...

Assessing Public Health Benefits of Replacing Freight Trucks with Cargo Cycles in Last Leg Delivery Trips in Urban Centers

Hartle, J
Elrahman, O
Wang, C
Rodriguez, D
Ding, Y
McGahan, M
2022

Increased urbanization, population growth, and demand for time-sensitive deliveries means increased freight movement in cities, which contributes to emissions, noise, and safety concerns. One innovative mode gaining widespread attention for urban deliveries is cargo cycles—bicycles adapted for freight delivery. Despite the recognized potential and possible success of transporting at least 25% of freight via cycle, research remains limited. This research investigates the potential of cargo cycle delivery for last mile freight in Oakland, California, with a focus on the West Oakland...

Marked Crosswalks in US Transit-oriented Station Areas, 2007–2020: A Computer Vision Approach Using Street View Imagery

Li, M
Sheng, H
Irvin, J
Chung, H
Ying, A
Sun, T
Ng, A
Rodriguez, D
2022
Improving the built environment to support walking is a popular strategy to increase urban sustainability and walkability. In the past decade alone, many US cities have implemented crosswalk visibility enhancement programs as part of road safety improvements and active transportation plans. However, there are no systematic ways of measuring and monitoring the presence of key built environment attributes that influence the safety and walkability of an area, such as marked crosswalks. Furthermore, little is known about how these attributes change over time at a national scale. In this paper, we...

Social Disparities in Flood Exposure and Associations with the Built Environment in 47,187 Urban Neighborhoods in Eight Latin American Countries

Kephart, JL
Bilal, U
Ferreira, A
Gouveia, N
Rodriguez, DA
Barbieri, IS
Miranda, J
Roux, AV Diez
2023
BACKGROUND AND AIM: Climate change is expected to greatly increase population exposure to flooding and related health impacts, particularly in urban areas of the Global South. We aimed to examine within-city social disparities in exposure to flooding within 326 Latin American cities and associated features of the neighborhood environment. METHOD: We used a high spatial resolution dataset of historical flood events from 2000-2018 to describe flood exposure at the neighborhood level for all cities with 100,000+ residents in eight Latin American countries (Argentina, Brazil, Chile, Colombia,...

Greenness and Excess Deaths from Heat in 323 Latin American Cities: Do Associations Vary According to Climate Zone or Green Space Configuration?

Schinasi, LH
Bakhtsiyarava, M
Sánchez, BN
Kephart, JL
Ju, Y
Arunachalam, S
Gouveia, N
Caiaffa, WT
O'Neill, MS
Dronova, I
Roux, AV Diez
Rodriguez, D
2023
Green vegetation may protect against heat-related death by improving thermal comfort. Few studies have investigated associations of green vegetation with heat-related mortality in Latin America or whether associations are modified by the spatial configuration of green vegetation. We used data from 323 Latin American cities and meta-regression models to estimate associations between city-level greenness, quantified using population-weighted normalized difference vegetation index values and modeled as three-level categorical terms, and excess deaths from heat (heat excess death fractions [heat...

Longitudinal Control of Commercial Heavy Vehicles Equipped with Variable Compression Brake

Moklegaard, Lasse
Druzhinina, Maria
Stefanopoulou, Anna G.
2002

In this report, we extend our previous work within MOU 372 on modeling and longitudinal speed control design for heavy commercial vehicles equipped with variable compression braking mechanisms. Previously, we developed a detailed crankangle based simulation model for a six cylinder, 350 hp diesel engine with a continuously varying compression brake that is capable of describing the intrinsic interactions between individual cylinder intake and exhaust processes, turbocharger dynamics during combustion and braking modes, and the transition between those modes. Moreover, for control design...

Conditions for Safe Deceleration of Strings of Vehicles

Lygeros, John
Lynch, Nancy
2000

A simple model for a string of vehicles is constructed. The model explicitly accounts for the possibility of repeated collisions between the vehicles in the string. Based on the model a notion of safety is formulated for the string. Necessary and sufficient conditions are presented that specify when a string of vehicles is safe while performing a simple emergency deceleration maneuver where all vehicles start decelerating at a fixed rate after some delay. The conditions are interpreted in terms of their implications for the safety of platoons of vehicles.