working paper

Product Differentiation on Roads: Second-Best Congestion Pricing with Heterogeneity under Public and Private Ownership

Publication Date

June 1, 1999

Author(s)

Erik T. Verhoef, Kenneth Small

Working Paper

UCI-ITS-WP-99-1

Areas of Expertise

Abstract

We explore the properties of various types of public and private pricing on a congested road network with heterogeneous users and allowing for elastic demand. Heterogeneity is represented by a continuum of values of time. The network consists of both serial and parallel links, which allows us to model second-best pricing restrictions on either complementary or substitute links, while still accounting for interaction between different groups on shared links (e.g. in city centres). We find that private (revenue-maximizing) pricing is much less efficient than public, whether on the partial or the full network; but this difference is mitigated by the product differentiation made possible by heterogeneous users. Ignoring heterogeneity causes the welfare benefits of second-best pricing of one parallel link, a policy currently receiving favourable consideration, to be dramatically underestimated Product differentiation produces some unexpected distributional effects, including the possibility that first-best pricing can result in one of the parallel routes being both more expensive and more congested than with no pricing.

Suggested Citation
Erik T. Verhoef and Kenneth A. Small (1999) Product Differentiation on Roads: Second-Best Congestion Pricing with Heterogeneity under Public and Private Ownership. Working Paper UCI-ITS-WP-99-1. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/8h45v1v3.

working paper

Estimation of Vehicular Emissions by Capturing Traffic Variations

Abstract

Increase in traffic volumes and changes in travel-related characteristics increase vehicular emissions significantly. It is difficult, however, to accurately estimate emissions with current practice because of the reliance on travel forecasting models that are based on steady state hourly averages and, thus, are incapable of capturing the effects of traffic variations in the transportation network. This paper proposes an intermediate model component that can provide better estimates of link speeds by considering a set of Emission Specific Characteristics (ESC) for each link. The intermediate model is developed using multiple linear regression; it is then calibrated, validated, and evaluated using a microscopic traffic simulation model. The improved link speed data can then be used to provide better estimates of emissions. The evaluation results show that the proposed emission estimation method performs better than current practice and is capable of estimating time-dependent emissions if traffic sensor data are available as model input.

Suggested Citation
K.S. Nesamani, Lianyu Chu, Michael G. McNally and R. Jayakrishnan (2005) Estimation of Vehicular Emissions by Capturing Traffic Variations. Working Paper UCI-ITS-WP-05-6. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/7gz0f9sf.

Phd Dissertation

Network-wide truck tracking using advanced point detector data

Abstract

Trucks contribute disproportionally to traffic congestion, emissions, road safety issues, and infrastructure and maintenance costs. In addition, truck flow patterns are known to vary by season and time-of-day as trucks serve different industries and facilities. Therefore, truck flow data are critical for transportation planning, freight modeling, and highway infrastructure design and operations. However, the current data sources only provide partial truck flow or point observations. This dissertation developed a framework for estimating path flows of trucks by tracking individual vehicles as they traverse detector stations over long distances. Truck physical attributes and inductive waveform signatures were collected from advanced point detector systems and used to match vehicles between detector locations by a Selective Weighted Bayesian Model (SWBM). The key feature variables that were the most influential in distinguishing vehicles were identified and emphasized in the SWBM to efficiently and successfully track vehicles across road networks. The initial results showed that the Bayesian approach with the full integration of two complementary detector data types – advanced inductive loop detectors and Weigh-in-Motion (WIM) sensors – could successfully track trucks over long distances (i.e., 26 miles) by minimizing the impacts of measurement variations and errors from the detection systems. The network implementation of the model demonstrated high coverage and accuracy, which affirmed the capability of the tracking approach to provide comprehensive truck travel patterns in a complex network. Specifically, the model was able to successfully match 90 percent of multi-unit trucks where only 67 percent of trucks observed at a downstream site passed an upstream detection site. A strategic plan to identify optimal sensor locations to maximize benefits from the truck tracking model was also proposed. A decision model that optimally locates sensors to capture the maximum truck OD and route flow was investigated using a goal programming approach. This approach suggested optimal locations for tracking implementation in a large truck network considering a limited budget. Results showed that sensor locations from a maximum-flow-capturing approach were more advantageous to observe truck flow than a conventional sensor location approach that focuses on OD and route identifiability.

Suggested Citation
Kyung Hyun (2016) Network-wide truck tracking using advanced point detector data. Ph.D.. UC Irvine. Available at: https://escholarship.org/uc/item/7jw638xt (Accessed: October 12, 2023).

conference paper

OTEM: Optimized thermal and energy management for hybrid electrical energy storage in electric vehicles

Proceedings of the 2016 design, automation & test in europe conference & exhibition (DATE)

Publication Date

January 1, 2016

Author(s)

Korosh Vatanparvar, Mohammad Al Faruque
Suggested Citation
Korosh Vatanparvar and Mohammad Abdullah Al Faruque (2016) “OTEM: Optimized thermal and energy management for hybrid electrical energy storage in electric vehicles”, in Proceedings of the 2016 design, automation & test in europe conference & exhibition (DATE). Research Publishing Services, pp. 19–24. Available at: 10.3850/9783981537079_0904.

conference paper

Battery lifetime-aware automotive climate control for electric vehicles

Proceedings of the 52nd annual design automation conference on - DAC '15

Publication Date

January 1, 2015

Author(s)

Korosh Vatanparvar, Mohammad Al Faruque
Suggested Citation
Korosh Vatanparvar and Mohammad Abdullah Al Faruque (2015) “Battery lifetime-aware automotive climate control for electric vehicles”, in Proceedings of the 52nd annual design automation conference on - DAC '15. ACM Press, pp. 1–6. Available at: 10.1145/2744769.2744804.

working paper

Why Do Inner City Residents Pay Higher Premiums? The Determinants of Automobile Insurance Premiums

Publication Date

January 1, 2008

Author(s)

Paul Ong

Abstract

Auto insurance rates can vary dramatically, with much higher premiums in poor and minority areas than elsewhere, even after accounting for individual characteristics, driving history and coverage. This project used a unique data set to examine the relative influence of place-based socioeconomic characteristics (or redlining) and place-based risk factors on the place-based component of automobile insurance premiums. We used a novel approach of combining tract-level census data and car insurance rate quotes from multiple companies for sub-areas within the city of Los Angeles. The quotes are for a hypothetical individual with identical demographic and auto characteristics, driving records and insurance coverage. This method allowed the individual demographic and driving record to be fixed. Multivariate models are then used to estimate the independent contributions of these risk and redlining factors to the place-based component of the car insurance premium. We find that both risk and redlining factors are associated with variations in insurance costs in the place-based component, with black and poor neighborhoods being adversely affected, although risk factors are stronger predictors. However, even after risk factors are taken into account in the model specification, SES factors remain statistically significant. Moreover, simulations show that redlining factors explain more of the gap in auto insurance premiums between black (and Latino) and white neighborhoods and between poor and nonpoor neighborhoods. The findings do not appear sensitive to the individual characteristics of the hypothetical driver.

research report

The personal travel assistant (PTA): Measuring the dynamics of human travel behavior

Abstract

A simple, continuously collected GPS sequence was investigated to determine whether it can be used to accurately measure human behavior. Hybrid Dynamic Mixed Network (HDMN) modeling techniques were applied to learn behaviors given an extended GPS data stream. A key design decision behind the proposed architecture was to use an Enterprise Service Bus (ESB) to provide a communication infrastructure among various components of the application. Personal Travel Assistants running on mobile devices like cell phones could help travelers change their travel plans when routes are affected by crashes or natural disasters.

Suggested Citation
Will Recker, James E. Marca, Craig Rindt and R. Dechter (2010) The personal travel assistant (PTA): Measuring the dynamics of human travel behavior. University of California Transportation Center, p. 46p. Available at: https://escholarship.org/uc/item/94s473v6.

published journal article

Intersectionality of individual and neighborhood-level adverse social determinants of health in early pregnancy

Pregnancy

Publication Date

January 1, 2025

Author(s)

Jameaka L. Hamilton, William A. Grobman, Jiqiang Wu, Lynn M. Yee, David Haas, Becky Mcneil, Brian Mercer, Hyagriv Simhan, Uma Reddy, Robert M. Silver, Samuel Parry, George Saade, Jun Wu, Courtney D. Lynch, Kartik K. Venkatesh

Abstract

Introduction Individual- and neighborhood-level social determinants of health (SDOH) have been assessed separately in pregnancy, but their relationship to one another remains uncertain. We investigated the intersectionality of three neighborhood-level SDOH measures with three individual-level SDOH measures. This was done to examine the concomitant experiences of multiple SDOH in pregnancy. Methods A secondary analysis of data from the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-To-Be. We assessed three neighborhood-level SDOH measures using geocoded participant home addresses in the first trimester at the census-tract level: (1) high socioeconomic disadvantage (in tertiles) by the 2015 Area Deprivation Index, (2) inadequate food access by the USDA Food Access Research Atlas, and (3) low walkability by the EPA National Walkability Score. We assessed three individual-level SDOH measures: low household income, lower educational attainment, and Medicaid insurance. We examined the combinations of these three neighborhood SDOH and three individual SDOH measures by graphical visualization and using statistical tests to assess overall differences in the distribution of these measures. Results Of 9588 nulliparous individuals, adverse neighborhood-level SDOH [high socioeconomic disadvantage (28%), inadequate food access (24%), and low walkability (66%)] and adverse individual-level SDOH [low household income (19%), lower educational attainment (23%), and Medicaid insurance (33%)] were common in early pregnancy. Six percent of individuals lived in a community with all three adverse neighborhood-level SDOH measures. Of those living in a community with at least two neighborhood-level SDOH measures, 23% lived in areas with inadequate food access and low walkability, 19% with high socioeconomic disadvantage and low walkability, and 1% with high socioeconomic disadvantage and inadequate food access. Overall, 23% lived in a community with no adverse neighborhood-level SDOH, and among this group, 88% had no adverse individual-level SDOH. There were significant differences in adverse individual-level SDOH based on whether individuals lived in a community with all three adverse neighborhood-level measures [low household income (39%), lower educational attainment (44%), Medicaid (55%)], any two measures [low household income (22%), lower educational attainment (27%), Medicaid (37%)], or only one measure [low household income (14%), lower educational attainment (17%), Medicaid (27%)] (p < 0.001 for all). Conclusion Among nulliparous individuals in early pregnancy, the frequency of adverse individual-level SDOH was generally higher when they lived in communities with more adverse neighborhood-level SDOH. Future approaches that identify and classify the multifaceted and multilevel nature of structural determinants as they relate to pregnancy outcomes are needed.

Suggested Citation
Jameaka L. Hamilton, William A. Grobman, Jiqiang Wu, Lynn M. Yee, David Haas, Becky Mcneil, Brian Mercer, Hyagriv Simhan, Uma Reddy, Robert M. Silver, Samuel Parry, George Saade, Jun Wu, Courtney D. Lynch and Kartik K. Venkatesh (2025) “Intersectionality of individual and neighborhood-level adverse social determinants of health in early pregnancy”, Pregnancy, 1(2), p. e70002. Available at: 10.1002/pmf2.70002.

working paper

Population and Employment Densities: Structure and Change

Publication Date

September 5, 1994

Associated Project

Working Paper

UCI-ITS-WP-93-5, UCTC 161

Areas of Expertise

Abstract

We examine spatial patterns and their changes during the 1970s for the Los Angeles region, by estimating monocentric and polycentric density functions for employment and population. Downtown Los Angeles is clearly identified as the statistical monocentric center of the region, and it is the most consistently strong center in the polycentric patterns. Polycentric models fit statistically better than monocentric models, and there was some shift in employment distribution toward a more polycentric pattern. These findings verify the existence of polycentricity in Los Angeles and demonstrate for the first time that employment and especially population follow a polycentric pattern based on exogenously defined employment centers. The results confirm that both employment and population became more dispersed during the 1970s.

Suggested Citation
Kenneth A. Small and Shunfeng Song (1994) Population and Employment Densities: Structure and Change. Working Paper UCI-ITS-WP-93-5, UCTC 161. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/6nk5v6b4.