Modeling

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.

Spatial and Temporal Utility Modeling to Increase Transit Ridership

Church, Richard L.
Noronha, Val
Lei, Ting
Corrigan, Wils
Burbidge, Shaunna
Marston, Jim
2005

The objective of this research project was to develop a better understanding of the possible alternatives that a large employment center, like the University of California at Santa Barbara, can adopt in order to better utilize transit, mitigate traffic, and reduce demand for on-site parking. Although this project was oriented to the UCSB campus, the techniques and approaches developed in this project were designed to be equally applicable elsewhere. There were three major elements of this project: 1) develop an understanding of commuting employees through the use of a survey, 2) identify...

Virtual Weigh Stations in California: A Preliminary Cost-Effectiveness Analysis

Santero, Nicholas
Nokes, William
Harvey, John
2005

A new technology known as Virtual Weigh Stations (VWS) is intended to transform data-collecting weigh-in-motion (WIM) sites to weight enforcement mechanisms. This study investigates the possible benefits to the highway pavements in California from potential use of VWS. The investigation proceeded in two steps: (1) determining the damage currently caused by overweight trucks and (2) modeling the potential pavement life saved with VWS. The data used for analysis is from the California Department of Transportation (Caltrans) WIM database.