Planning hierarchical urban transit systems for reductions in greenhouse gas emissions

Han Cheng, Samer Madanat, Arpad Horvath

    Research output: Contribution to journalArticle

    Abstract

    Public transit systems with high occupancy can reduce greenhouse gas (GHG) emissions relative to low-occupancy transportation modes, but current transit systems have not been designed to reduce environmental impacts. This motivates the study of the benefits of design and operational approaches for reducing the environmental impacts of transit systems. For example, transit agencies may replace level-of-service (LOS) by vehicle miles traveled (VMT) as a criterion in evaluating design and operational changes. In previous work, we explored the unintended consequences of lowering transit LOS on emissions in a single-technology transit system. Herein, we extend the analysis to account for a more realistic case: a transit system with a hierarchical structure (trunk and feeder lines) providing service to a city where demand is elastic. By considering the interactions between the trunk and the feeder systems, we provide a quantitative basis for designing and operating integrated urban transit systems that can reduce GHG emissions and societal costs. We find that highly elastic transit demand may cancel emission reduction potentials resulting from lowering LOS, due to demand shifts to lower occupancy vehicles. However, for mass transit modes, these potentials are still significant. Transit networks with buses, bus rapid transit or light rail as trunk modes should be designed and operated near the cost-optimal point when the demand is highly elastic, while this is not required for metro. We find that the potential for unintended consequences increases with the size of the city. Our results are robust to uncertainties in the costs and emissions parameters.

    Original languageEnglish (US)
    Pages (from-to)44-58
    Number of pages15
    JournalTransportation Research Part D: Transport and Environment
    Volume49
    DOIs
    StatePublished - Dec 1 2016

    Fingerprint

    Gas emissions
    urban planning
    Greenhouse gases
    greenhouse gas
    Planning
    Environmental impact
    Costs
    Rapid transit
    environmental impact
    cost
    transportation mode
    demand
    Rails
    costs
    services
    planning
    uncertainty
    interaction
    city
    bus

    Keywords

    • Elasticity
    • Feeder transit
    • Greenhouse gas emission
    • Transit system design

    ASJC Scopus subject areas

    • Civil and Structural Engineering
    • Transportation
    • Environmental Science(all)

    Cite this

    Planning hierarchical urban transit systems for reductions in greenhouse gas emissions. / Cheng, Han; Madanat, Samer; Horvath, Arpad.

    In: Transportation Research Part D: Transport and Environment, Vol. 49, 01.12.2016, p. 44-58.

    Research output: Contribution to journalArticle

    @article{26fad1344586433eb3a729d256b2b9a6,
    title = "Planning hierarchical urban transit systems for reductions in greenhouse gas emissions",
    abstract = "Public transit systems with high occupancy can reduce greenhouse gas (GHG) emissions relative to low-occupancy transportation modes, but current transit systems have not been designed to reduce environmental impacts. This motivates the study of the benefits of design and operational approaches for reducing the environmental impacts of transit systems. For example, transit agencies may replace level-of-service (LOS) by vehicle miles traveled (VMT) as a criterion in evaluating design and operational changes. In previous work, we explored the unintended consequences of lowering transit LOS on emissions in a single-technology transit system. Herein, we extend the analysis to account for a more realistic case: a transit system with a hierarchical structure (trunk and feeder lines) providing service to a city where demand is elastic. By considering the interactions between the trunk and the feeder systems, we provide a quantitative basis for designing and operating integrated urban transit systems that can reduce GHG emissions and societal costs. We find that highly elastic transit demand may cancel emission reduction potentials resulting from lowering LOS, due to demand shifts to lower occupancy vehicles. However, for mass transit modes, these potentials are still significant. Transit networks with buses, bus rapid transit or light rail as trunk modes should be designed and operated near the cost-optimal point when the demand is highly elastic, while this is not required for metro. We find that the potential for unintended consequences increases with the size of the city. Our results are robust to uncertainties in the costs and emissions parameters.",
    keywords = "Elasticity, Feeder transit, Greenhouse gas emission, Transit system design",
    author = "Han Cheng and Samer Madanat and Arpad Horvath",
    year = "2016",
    month = "12",
    day = "1",
    doi = "10.1016/j.trd.2016.08.033",
    language = "English (US)",
    volume = "49",
    pages = "44--58",
    journal = "Transportation Research, Part D: Transport and Environment",
    issn = "1361-9209",
    publisher = "Elsevier Limited",

    }

    TY - JOUR

    T1 - Planning hierarchical urban transit systems for reductions in greenhouse gas emissions

    AU - Cheng, Han

    AU - Madanat, Samer

    AU - Horvath, Arpad

    PY - 2016/12/1

    Y1 - 2016/12/1

    N2 - Public transit systems with high occupancy can reduce greenhouse gas (GHG) emissions relative to low-occupancy transportation modes, but current transit systems have not been designed to reduce environmental impacts. This motivates the study of the benefits of design and operational approaches for reducing the environmental impacts of transit systems. For example, transit agencies may replace level-of-service (LOS) by vehicle miles traveled (VMT) as a criterion in evaluating design and operational changes. In previous work, we explored the unintended consequences of lowering transit LOS on emissions in a single-technology transit system. Herein, we extend the analysis to account for a more realistic case: a transit system with a hierarchical structure (trunk and feeder lines) providing service to a city where demand is elastic. By considering the interactions between the trunk and the feeder systems, we provide a quantitative basis for designing and operating integrated urban transit systems that can reduce GHG emissions and societal costs. We find that highly elastic transit demand may cancel emission reduction potentials resulting from lowering LOS, due to demand shifts to lower occupancy vehicles. However, for mass transit modes, these potentials are still significant. Transit networks with buses, bus rapid transit or light rail as trunk modes should be designed and operated near the cost-optimal point when the demand is highly elastic, while this is not required for metro. We find that the potential for unintended consequences increases with the size of the city. Our results are robust to uncertainties in the costs and emissions parameters.

    AB - Public transit systems with high occupancy can reduce greenhouse gas (GHG) emissions relative to low-occupancy transportation modes, but current transit systems have not been designed to reduce environmental impacts. This motivates the study of the benefits of design and operational approaches for reducing the environmental impacts of transit systems. For example, transit agencies may replace level-of-service (LOS) by vehicle miles traveled (VMT) as a criterion in evaluating design and operational changes. In previous work, we explored the unintended consequences of lowering transit LOS on emissions in a single-technology transit system. Herein, we extend the analysis to account for a more realistic case: a transit system with a hierarchical structure (trunk and feeder lines) providing service to a city where demand is elastic. By considering the interactions between the trunk and the feeder systems, we provide a quantitative basis for designing and operating integrated urban transit systems that can reduce GHG emissions and societal costs. We find that highly elastic transit demand may cancel emission reduction potentials resulting from lowering LOS, due to demand shifts to lower occupancy vehicles. However, for mass transit modes, these potentials are still significant. Transit networks with buses, bus rapid transit or light rail as trunk modes should be designed and operated near the cost-optimal point when the demand is highly elastic, while this is not required for metro. We find that the potential for unintended consequences increases with the size of the city. Our results are robust to uncertainties in the costs and emissions parameters.

    KW - Elasticity

    KW - Feeder transit

    KW - Greenhouse gas emission

    KW - Transit system design

    UR - http://www.scopus.com/inward/record.url?scp=84985947068&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=84985947068&partnerID=8YFLogxK

    U2 - 10.1016/j.trd.2016.08.033

    DO - 10.1016/j.trd.2016.08.033

    M3 - Article

    AN - SCOPUS:84985947068

    VL - 49

    SP - 44

    EP - 58

    JO - Transportation Research, Part D: Transport and Environment

    JF - Transportation Research, Part D: Transport and Environment

    SN - 1361-9209

    ER -