published journal article

Operational benefits and challenges of shared-ride automated mobility-on-demand services

Transportation Research Part A: Policy and Practice

Publication Date

April 1, 2020

Author(s)

Michael Hyland, Hani Mahmassani

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Abstract

This paper presents a quantitative analysis of the operations of shared-ride automated mobility-on-demand services (SRAMODS). The study identifies (i) operational benefits of SRAMODS including improved service quality and/or lower operational costs relative to automated mobility-on-demand services (AMODS) without shared rides; and (ii) challenges associated with operating SRAMODS. The study employs an agent-based stochastic dynamic simulation framework to model the operational problems of AMODS. The agents include automated vehicles (AVs), on-demand user requests, and a central AV fleet controller that can dynamically change the plans (i.e. routes and AV-user assignments) of AVs in real-time using optimization-based control policies. The agent-based simulation tool and AV fleet control policies are used to test the operational performance of AMODS under a variety of scenarios. The first set of scenarios vary user demand and a parameter constraining the maximum user detour distance. Results indicate that even with a small maximum user detour distance parameter value, allowing shared rides significantly improves the operational efficiency of the AV fleet, where the efficiency gains stem from economies of demand density and network effects. The second set of scenarios vary the mean and coefficient of variation of the curbside pickup time parameter; i.e. how long an AV must wait curbside at a user’s pickup location before the user gets inside the AV. Results indicate that increases in mean curbside pickup time significantly degrade operational performance in terms of user in-vehicle travel time and user wait time. The study quantifies the total system (user plus fleet controller) cost as a function of mean curbside pickup time. Finally, the paper provides an extensive discussion of the implications of the quantitative analysis for public-sector transportation planners and policy-makers as well as for mobility service providers.

Suggested Citation

Michael Hyland and Hani S. Mahmassani (2020) “Operational benefits and challenges of shared-ride automated mobility-on-demand services”, Transportation Research Part A: Policy and Practice, 134, pp. 251–270. Available at: 10.1016/j.tra.2020.02.017.

published journal article

The impact of long-term exposure to traffic-related air pollution and genetic susceptibility on Parkinson’s disease

ISEE Conference Abstracts

Publication Date

August 15, 2024

Author(s)

Dayoon Kwon, Cynthia Kusters, Kimberly Paul, Jun Wu, Jeff Bronstein, Christina Lill, Beate Ritz

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Abstract

BACKGROUND AND AIM[|]Although environmental and genetic factors have been linked to Parkinson’s disease (PD), the influence of genetic susceptibility on the association between long-term exposure to traffic-related air pollution and PD is not well understood.[¤]METHOD[|]Our case-control analysis included 664 PD and 733 population controls, who also provided blood samples. We estimated annual average traffic-related air pollutant concentrations (represented by carbon monoxide; CO) at residential and workplace locations from 1981 to 2016 using the California Line Source Dispersion Model version 4. Long-term exposures were calculated as 10-year averages with a 5-year lag time prior to a PD diagnosis for cases and the interview date for controls and we categorized it as high/low using a median cut. A polygenic risk score (PRS) was computed by summing the effect estimates of well-known risk alleles from existing genome-wide association studies (GWAS) summary statistics with data from individuals genetic array to assess individual genetic risks for PD. Logistic regression models were employed to estimate odds ratios (OR) and 95% confidence interval (CI), adjusting for age, race, sex, education, and study wave, for the effect of genetic risk on the association between air pollution exposure and PD risk.[¤]RESULTS[|]The OR for PD among individuals with high PD-PRS risk (> median) and high CO exposure (> median) at residences was 2.55 (95% CI: 1.86, 3.48) and 3.62 (2.11, 6.18) at workplaces compared to individuals with low PD-PRS and low CO. Gene-environment interactions were observed on a multiplicative scale (p = 0.05) at residential locations.[¤]CONCLUSIONS[|]Our findings suggest that a combination of long-term exposure to air pollution from traffic and genetic susceptibility contributes to the risk of developing PD.[¤]

Suggested Citation

Dayoon Kwon, Cynthia Kusters, Kimberly Paul, Jun Wu, Jeff Bronstein, Christina Lill and Beate Ritz (2024) “The impact of long-term exposure to traffic-related air pollution and genetic susceptibility on Parkinson’s disease”, ISEE Conference Abstracts, 2024(1). Available at: 10.1289/isee.2024.1369.

published journal article

Real-time traffic measurement from single loop inductive signatures

Transportation Research Record

Publication Date

January 1, 2002

Author(s)

Seri Park, Stephen Ritchie, Cheol Oh

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Suggested Citation

Seri Oh, Stephen G. Ritchie and Cheol Oh (2002) “Real-time traffic measurement from single loop inductive signatures”, Transportation Research Record, 1804(1), pp. 98–106. Available at: 10.3141/1804-14.

conference paper

New inductive signature data compression and transformation method for online vehicle reidentification

Transportation Research Board 85th Annual Meeting

Publication Date

January 1, 2006

Author(s)

Shin-Ting (Cindy) Jeng, Stephen Ritchie

Abstract

Traffic operations field computational resources as well as the bandwidth of field communication links are often quite limited. Accordingly, for on-line implementation of Advanced Transportation Management and Information Systems (ATMIS) strategies, such as vehicle reidentification, there is strong interest in development of field—based techniques and models that can perform satisfactorily while minimizing field computational and communication requirements. A new vehicle reidentification algorithm (REID-2) developed previously by the authors (1) was oriented toward algorithm simplification, but also demonstrated the added benefits of improved performance and much broader potential applicability (to both round and square single inductive loops) compared with earlier methods. However, the basis of REID-2 is directly matching inductive vehicle signatures, which typically consist of 200~1,200 data points (stored as integers, and obtained from IST-222 detector cards) per signature. The purpose of this research was to investigate if a relatively simple data compression and transformation technique could be applied successfully to the raw inductive signatures for each vehicle, and then use the resulting transformed vehicle signatures as inputs to vehicle reidentification. A Piecewise Slope Rate (PSR) approach was used to compress and transform the raw vehicle signatures. The results of this investigation, including sensitivity analyses, vehicle reidentification performance, and the accuracy of section travel time measurement, are very promising and suggest that the reduction in both computational effort and computer memory needed to store individual signatures with this approach could potentially benefit both the field computational and communication requirements needed for real-time implementation of this modified vehicle reidentification technique.

Suggested Citation

Shin-Ting Cindy Jeng and Stephen G Ritchie (2006) “New inductive signature data compression and transformation method for online vehicle reidentification”.

conference paper

On the Vulnerability of Traffic Light Recognition Systems to Laser Illumination Attacks

ISOC Symposium on Vehicle Security and Privacy (VehicleSec). ISOC, San Diego, CA, USA. https://doi. org/10

Publication Date

January 1, 2024

Author(s)

Sri Hrushikesh Varma Bhupathiraju, Takeshi Sugawara, Takami Sato, Qi Alfred Chen, Michael Clifford, Sara Rampazzi

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Suggested Citation

Sri Hrushikesh Varma Bhupathiraju, Takeshi Sugawara, Takami Sato, Qi Alfred Chen, Michael Clifford and Sara Rampazzi (2024) “On the Vulnerability of Traffic Light Recognition Systems to Laser Illumination Attacks”, in ISOC Symposium on Vehicle Security and Privacy (VehicleSec). ISOC, San Diego, CA, USA. https://doi. org/10. Available at: https://www.ndss-symposium.org/wp-content/uploads/vehiclesec2024-24-paper.pdf (Accessed: September 13, 2024).

published journal article

Gentrification and neighborhood housing cycles: Will America's future downtowns be rich?

Review of Economics and Statistics

Publication Date

November 1, 2009

Author(s)

Jan Brueckner, Stuart S Rosenthal

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Abstract

This paper identifies a new factor, the age of the housing stock, that affects where high- and low-income neighborhoods are located in U.S. cities. High-income households, driven by a high demand for housing services, tend to locate in areas of the city where the housing stock is relatively young. Because cities develop and redevelop from the center outward over time, the location of these neighborhoods varies over the city’s history. The model predicts a suburban location for the rich in an initial period, when young dwellings are found only in the suburbs, while predicting eventual gentrification once central redevelopment creates a young downtown housing stock. Controlling for other determinants of where the poor live (e.g., proximity to amenities and public transit), empirical work indicates that if the influence of spatial variation in dwelling ages were eliminated, central-city/suburban disparities in neighborhood economic status would be reduced by up to 10 percentage points. Model estimates further predict that between 2000 and 2020, central-city/suburban differences in economic status will narrow in cities of all sizes, and especially in the larger metropolitan areas as American cities become more gentrified.

Suggested Citation

Jan K Brueckner and Stuart S Rosenthal (2009) “Gentrification and neighborhood housing cycles: Will America's future downtowns be rich?”, Review of Economics and Statistics, 91(4), pp. 725–743. Available at: 10.1162/rest.91.4.725.

published journal article

Using longitudinal methods for analysis of a short-term transportation demonstration project

Transportation

Publication Date

January 1, 1990

Author(s)

Genevieve (Gen) Giuliano, Thomas Golob

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Suggested Citation

Genevieve Giuliano and Thomas F. Golob (1990) “Using longitudinal methods for analysis of a short-term transportation demonstration project”, Transportation, 17(1), pp. 1–28. Available at: 10.1007/bf02125501.

published journal article

Trucking industry preferences for traveler information for drivers using wireless Internet-enabled devices

Transportation Research Part C: Emerging Technologies

Publication Date

June 1, 2005

Author(s)

Thomas Golob, Amelia Regan

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Abstract

This study investigates what type of information truck drivers would want to have if they could use Internet-enabled wireless devices to access traveler information. Preferences from managers of 700 for-hire trucking companies and private trucking fleets were analyzed to determine how they valued information about such things as locations of freeway incidents and lane closures, port and rail terminal schedules and clearances, delays at terminals, train arrivals at grade crossings, weather, and travel times on alternative routes. Using a factor-analytic model with regressor variables, the authors found that perceptions of the value of specific sources of traffic information are related to the operating characteristics of the trucking companies.

Suggested Citation

Thomas F. Golob and Amelia C. Regan (2005) “Trucking industry preferences for traveler information for drivers using wireless Internet-enabled devices”, Transportation Research Part C: Emerging Technologies, 13(3), pp. 235–250. Available at: 10.1016/j.trc.2004.08.002.

working paper

Estimating the Full Economic Costs of Truck Incidents on Urban Freeways

Publication Date

November 1, 1988

Author(s)

Roger Teal

Working Paper

UCI-ITS-WP-88-11

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Abstract

This study uses Los Angeles County as the setting for examining the full economic costs of truck-related freeway incidents. Los Angeles County was selected as a setting due to its size–over 7.5 million population in an area of 4,080 square miles, the highly developed nature of its freeway system (504 miles of freeway), the heavy truck traffic on that system (over 12 million truck miles of travel per day), and the availability of data to facilitate analysis of this problem. Another reason for using Los Angeles as the site for this study is that truck-related incidents are a significant and growing problem on the Los Angeles freeway system, one which the California Department of Transportation is also examining. The majority of major incidents on the Los Angeles freeway system involve one or more trucks. During 1983, 1984, and 1985, 424 major incidents–defined as an incident which closes at least two lanes and is predicted to last at least two hours–involving trucks occurred on the freeway system. In other words, a major truck-related incident occurred nearly three out of every five working days of the week. Moreover, data collected for this study indicates that 6,700 to 8,000 total truck incidents occur annually on the Los Angeles County freeway system, or approximately 20 to 25 truck incidents per weekday. The scope of the problem in Los Angeles makes it an excellent setting for analyzing the costs of truck-related freeway incidents.

Suggested Citation

Roger F. Teal (1988) Estimating the Full Economic Costs of Truck Incidents on Urban Freeways. Working Paper UCI-ITS-WP-88-11. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/8vt3q1m7.

conference paper

Open doors for bob and mallory: Open port usage in android apps and security implications

2017 IEEE european symposium on security and privacy (EuroS&P)

Publication Date

April 1, 2017

Author(s)

Yunhan Jack Jia, Qi Alfred Chen, Yikai Lin, Chao Kong, Z. Morley Mao

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Suggested Citation

Yunhan Jack Jia, Qi Alfred Chen, Yikai Lin, Chao Kong and Z. Morley Mao (2017) “Open doors for bob and mallory: Open port usage in android apps and security implications”, in 2017 IEEE european symposium on security and privacy (EuroS&P). IEEE, pp. 190–203. Available at: 10.1109/eurosp.2017.44.