published journal article

Promoting peer-to-peer ridesharing services as transit system feeders

Transportation Research Record

Publication Date

January 1, 2017

Author(s)

Neda Masoud, Daisik (Danny) Nam, Jiangbo (Gabe) Yu, R. (Jay) Jayakrishnan

View published journal article

Abstract

Peer-to-peer (P2P) ridesharing is a recently emerging travel alternative that can help accommodate the growth in urban travel demand and at the same time alleviate problems such as excessive vehicular emissions. Prior ridesharing projects suggest that the demand for ridesharing is usually shifted from transit, but its true benefits are realized when the demand shifts from single-occupancy vehicles. This study investigated the potential of shifting demand from private autos to transit by providing a general modeling framework that found routes for private vehicle users that were a combination of P2P ridesharing and transit. The Los Angeles Metro Red Line in California was considered for a case study because it has recently shown declining ridership trends. For successful implementation of a ridesharing system, strategically selecting locations for individuals to get on and off the rideshare vehicles is crucial, along with an appropriate pricing structure for the rides. The study conducted a parametric analysis of the application of real-time P2P ridesharing to feed the Los Angeles Metro Red Line with simulated demand. A mobile application with an innovative ride-matching algorithm was developed as a decision support tool that suggested transit-rideshare and rideshare routes.

Suggested Citation

Neda Masoud, Daisik Nam, Jiangbo Yu and R. Jayakrishnan (2017) “Promoting peer-to-peer ridesharing services as transit system feeders”, Transportation Research Record, 2650(1), pp. 74–83. Available at: 10.3141/2650-09.

conference paper

Multicommodity kinematic wave simulation model for network traffic flow

TRAFFIC FLOW THEORY AND HIGHWAY CAPACITY AND QUALITY OF SERVICES 2004

Publication Date

January 1, 2004

Author(s)

Wenlong Jin, HM Zhang

Abstract

A multicommodity discrete kinematic wave model that possesses the theoretical rigor and computational efficiency inherent in the kinematic wave theory is proposed for simulating network traffic flow. In this model, fluxes through boundaries and junctions are computed systematically under the supply-demand framework. In addition, traffic is modeled by commodity type so that the effects of geometric characteristics of a road network on traffic dynamics can be captured. Although traffic is not ordered down to the vehicle level as in existing kinematic wave simulation models, the noncompliance with the first-in-first-out property in this model is still of the order of At, the time increment. Hence travel times in the average sense can be defined from cumulative curves. Finally, the evolution of traffic dynamics in a sample road network is shown to demonstrate the stability, numerical convergence, and soundness of the proposed network kinematic wave model.

Suggested Citation

WL Jin and HM Zhang (2004) “Multicommodity kinematic wave simulation model for network traffic flow”, in TRAFFIC FLOW THEORY AND HIGHWAY CAPACITY AND QUALITY OF SERVICES 2004. TRANSPORTATION RESEARCH BOARD NATL RESEARCH COUNCIL, pp. 59–67.

published journal article

roadscene2vec: A tool for extracting and embedding road scene-graphs

Knowledge-Based Systems

Publication Date

April 22, 2022

Author(s)

Arnav Vaibhav Malawade, Shih-Yuan Yu, Brandon Hsu, Harsimrat Kaeley, Anurag Karra, Mohammad Al Faruque

View published journal article

Abstract

Recently, road scene-graph representations used in conjunction with graph learning techniques have been shown to outperform state-of-the-art deep learning techniques in tasks including action classification, risk assessment, and collision prediction. To enable the exploration of applications of road scene-graph representations, we introduce roadscene2vec: an open-source tool for extracting and embedding road scene-graphs. The goal of roadscene2vec is to enable research into the applications and capabilities of road scene-graphs by providing tools for generating scene-graphs, graph learning models to create spatio-temporal scene-graph embeddings, and tools for visualizing and analyzing scene-graph-based methodologies. The capabilities of roadscene2vec include (i) customized scene-graph generation from either video clips or data from the CARLA simulator, (ii) multiple configurable spatio-temporal graph embedding models and baseline CNN-based models, (iii) built-in functionality for using graph and sequence embeddings for risk assessment and collision prediction applications, (iv) tools for evaluating transfer learning, and (v) utilities for visualizing scene-graphs and analyzing the explainability of graph learning models. We demonstrate the utility of roadscene2vec for these use cases with experimental results and qualitative evaluations for both graph learning models and CNN-based models. roadscene2vec is available at https://github.com/AICPS/roadscene2vec.

Suggested Citation

Arnav Vaibhav Malawade, Shih-Yuan Yu, Brandon Hsu, Harsimrat Kaeley, Anurag Karra and Mohammad Abdullah Al Faruque (2022) “roadscene2vec: A tool for extracting and embedding road scene-graphs”, Knowledge-Based Systems, 242, p. 108245. Available at: 10.1016/j.knosys.2022.108245.

published journal article

Local labor markets, job matching, and urban location*

Int Economic Rev

Publication Date

February 1, 2002

Author(s)

Jan Brueckner, Jacques-Francois Thisse, Yves Zenou

View published journal article

Abstract

We present a new way of modeling local labor markets by linking the space of workers’ skills and the physical space of cities. The key lesson of our analysis is that firms exploit workers in these two spaces by setting wages that are below the competitive level. The degree of monopsony power depends on the elasticity of the firm’s labor pool, which is inversely related to the costs workers incur in commuting and acquiring skills. Our analysis thus shows how socioeconomic ghettos emerge as workers with poor skill matches are also those who incur the highest commuting costs.

Suggested Citation

Jan K. Brueckner, Jacques-Francois Thisse and Yves Zenou (2002) “Local labor markets, job matching, and urban location*”, Int Economic Rev, 43(1), pp. 155–171. Available at: 10.1111/1468-2354.t01-1-00007.

working paper

Economics and Urban Transportation Policy in the United States

Publication Date

January 1, 1997

Associated Project

UCTC: (1991) ISTEA version

Author(s)

Kenneth Small

Areas of Expertise

Transportation Economics, Funding, & Finance

View working paper

Abstract

This article examines the role that economics can play in analysing problems with urban transportation in the United States. The specific problems addressed are failing infrastructure, financially weak public transit, environmental impacts of motor vehicles, motor-vehicle accidents, and traffic congestion. Simple quantitative analyses, even though approximate, can help to focus attention on the most promising classes of policies. Those classes involve some technological measures and some narrowly targeted behavioral changes, but not the widespread curtailment of of motor vehicles use.

Related Publications

working paper | Aug 1993

Competition and Prices in the Deregulated Gas Pipeline Network: A Multivariate Cointegration Analysis

working paper | Oct 1993

Ameliorating Congestion by Income Redistribution

book/book chapter | Oct 1998

Project Evaluation

working paper | Sep 1995

On the Costs of Air Pollution from Motor Vehicles

working paper | Sep 1994

Population and Employment Densities: Structure and Change

published journal article

Employment deconcentration and spatial dispersion in metropolitan areas: Consequences for commuting patterns

Cities

Publication Date

December 1, 2022

Author(s)

John R. Hipp, Sugie Lee, Jae Hong Kim, Benjamin Forthun

View published journal article

Abstract

There is interest in understanding which characteristics of metropolitan areas impact the length of time or distance residents spend commuting. We utilize two measures recently introduced to the urban literature capturing distinct dimensions of employment decentralization –the level of employment deconcentration and employment spatial dispersion in metropolitan areas – to assess how they are related to commuting patterns across metropolitan areas. These two measures of urban/metropolitan spatial structure avoid challenges in identifying “job centers” and allow for a more systematic investigation of how employment decentralization affects commuting patterns. Furthermore, we detect key differences for the implications of these measures for commuting across 329 US metropolitan regions based on their population size. We find that greater employment deconcentration in very small MSAs is associated with longer commute times and distances, whereas greater employment deconcentration in large or very large MSAs is associated with shorter commutes. And whereas spatial dispersion is not related to commute times in very small MSAs, greater spatial dispersion is associated with longer commutes in very large MSAs. This study also shows that the spatial pattern of employment in regions, captured by these new measures, is associated with the proportion of very short and very long duration commutes.

Suggested Citation

John R. Hipp, Sugie Lee, Jae Hong Kim and Benjamin Forthun (2022) “Employment deconcentration and spatial dispersion in metropolitan areas: Consequences for commuting patterns”, Cities, 131, p. 103947. Available at: 10.1016/j.cities.2022.103947.

published journal article

A Program in Social and Urban Systems Engineering

Engineering Education

Publication Date

January 1, 1974

Author(s)

Will Recker, G. C. Lee, R. E. Paaswell

View published journal article

Suggested Citation

W. W. Recker, G. C. Lee and R. E. Paaswell (1974) “A Program in Social and Urban Systems Engineering”, Engineering Education, 64(4), pp. 275–278. Available at: https://eric.ed.gov/?id=EJ091711.

published journal article

Atomistic congestion tolls at concentrated airports? Seeking a unified view in the internalization debate

Journal of Urban Economics

Publication Date

September 1, 2008

Author(s)

Jan Brueckner, Kurt van-Dender

View published journal article

Suggested Citation

Jan K. Brueckner and Kurt Van Dender (2008) “Atomistic congestion tolls at concentrated airports? Seeking a unified view in the internalization debate”, Journal of Urban Economics, 64(2), pp. 288–295. Available at: 10.1016/j.jue.2008.02.002.

research report

Evaluation of the Air Quality and Greenhouse Gas Benefits of an Advanced Low‐NOx Compressed Natural Gas (CNG) Engine in Medium and Heavy‐Duty Vehicles in California

Publication Date

June 1, 2017

Associated Project

Evaluation of the Air Quality and Greenhouse Gas Benefits of an Advanced Low‐NOx Compressed Natural Gas (CNG) Engine in Medium and Heavy‐Duty Vehicles in California

Author(s)

Michael Mackinnon, Brendan Shaffer, Alejandra Cervantes, Scott Samuelsen

Areas of Expertise

Freight, Logistics, & Supply Chain Zero-Emission Vehicles & Low-Carbon Fuels

View research report

Abstract

The goal of this research is to assess the greenhouse gas (GHG) emissions and air quality (AQ) impacts of transitions to advanced low‐NOx Compressed Natural Gas (CNG) engines in medium-duty vehicle (MDV) and heavy-duty vehicle (HDV) applications in California with a particular emphasis on renewable natural gas (RNG) as a fueling pathway. To evaluate regional AQ impacts in 2035, pollutant emissions from all end-use sectors are projected from current levels and spatially and temporally resolved. Scenarios are constructed beginning with both a conservative (Base Case) and more optimistic (SIP) case regarding advanced vehicle technology and fuels integration to provide spanning of potential impacts. To capture the impact of seasonal dynamics on pollutant formation and fate, two modeling periods are conducted including a winter and summer episode. To estimate the potential GHG impacts of transitions to advanced CNG engines in HDV and MDV, scenarios are evaluated under various assumptions regarding fuel pathways to meet CNG demand from a life cycle perspective. Scenarios are compared to the baseline cases assuming (1) all CNG is provided from conventional fossil natural gas and (2) under a range of possible resource availabilities associated with RNG and renewable synthetic natural gas (RSNG) from in-state resources. Key findings include: i) expanding the deployment of advanced CNG MDV and HDV can reduce summer ground-level ozone concentrations and groundlevel PM2.5 in key regions of California; ii) the largest AQ benefits are associated with reducing emissions from HDV; iii) in-state RNG pathways can meet the CNG demand estimated for both baseline cases; iv) in-state resources are unable to entirely meet CNG demand for the high total CNG demand estimated for the majority of Base alternative cases, and v) advanced CNG HDV and MDV can moderately reduce GHG emissions if fossil natural gas is used (14 to 26%).

Suggested Citation

Michael MacKinnon, Brendan Shaffer, Alejandra Cervantes and G. Scott Samuelsen (2017) Evaluation of the Air Quality and Greenhouse Gas Benefits of an Advanced Low‐NOx Compressed Natural Gas (CNG) Engine in Medium and Heavy‐Duty Vehicles in California. Available at: https://escholarship.org/uc/item/9841k55n (Accessed: October 11, 2023).

Related Publications

policy brief | May 2017

Advanced Low-NOx Compressed Natural Gas Engines in Medium- and Heavy-Duty Vehicles Are Poised to Deliver Air Quality Benefits and Advance California’s Climate Goals

conference paper

Incorporating yellow-page databases in GIS-based transportation models

Transportation, land use, and air quality, conference proceedings: Making the connection

Publication Date

January 1, 1998

Author(s)

MS Lee, Michael McNally

Abstract

A systematic approach is developed to transform data in the existing yellow-page databases to a point-based GIS database on activity supply, Such a database is needed for an activity-based travel forecasting system and for disaggregate accessibility analysis. First, the linkage between activity types and business types is established. According to this lookup relationship, businesses and services associated with certain activity types can be selected, These records are then geocoded by address-matching in a GIS and the locations supplying those activities are pinned down. Technical issues, such as difficulty in linking businesses to activities, long term projection, and address-matching, are discussed and potential solutions are provided. Finally, issues that need to be addressed when attempting to develop an activity-based forecasting system are examined from the perspective of activity supply.

Suggested Citation

MS Lee and MG McNally (1998) “Incorporating yellow-page databases in GIS-based transportation models”, in . Easa, S and Samdahl, D (ed.) Transportation, land use, and air quality, conference proceedings: Making the connection. AMER SOC CIVIL ENGINEERS, pp. 652–661.