Providing bus priority at signalized intersections with single-lane approaches

S. Ilgin Guler, Vikash V. Gayah, Monica Menendez

    Research output: Contribution to journalArticle

    Abstract

    Signalized intersections often represent a major source of bus delays. One typical strategy to mitigate this problem is to dedicate an existing car lane for bus-use only to minimize the interactions between cars and buses. However, this is physically impossible at approaches where only a single travel lane is available for each direction. To this end, this research explores a novel method to provide priority to buses at signalized intersections with single-lane approaches through the use of additional signals in a way that (nearly) eliminates bus delays while minimizing the negative impacts imparted to cars. Using these signals, the bus can jump a portion of the car queue using the travel lane in the opposite direction. This paper theoretically quantifies the delay savings buses can achieve, and the negative impacts imparted onto cars when this pre-signal strategy is applied. The negative impacts are measured as the additional car delays experienced when the intersection signal is under-saturated, and the reduction in car-discharge capacity when the intersection signal is over-saturated. In the under- saturated case, the results show that moderate average bus delay savings (∼5-7 seconds per vehicle) are achieved if the pre-signal is always in operation; and these results decrease the total system-wide delay (measured in person-hours) only if bus occupancies are very high. However, if the pre-signal operation is targeted to only provide priority to the buses that would benefit the most, significant bus delay savings can be achieved (delay benefits to buses which receive priority are about doubled) while also reducing the system-wide delay, even if the ratio of bus to car occupancy is relatively modest (greater than about 20). In the over-saturated case, bus delay savings can be much more significant than under-saturated cases (greater than 30 seconds per bus), and this delay saving can increase further for longer block lengths (greater than 100 m). However, the capacity of the intersection decreases by up to 25% during each cycle in which a bus arrives to the intersection. Simulation tests confirmed that the general trends and magnitudes of bus delay savings and negative impacts to cars hold for more realistic behaviors. The overall benefits are slightly smaller in the simulations, but nevertheless the strategy seems promising as a bus priority strategy at intersections with single-lane approaches in the field.

    Original languageEnglish (US)
    Pages (from-to)225-245
    Number of pages21
    JournalTransportation Research Procedia
    Volume9
    DOIs
    StatePublished - Jan 1 2015

    Fingerprint

    savings
    Railroad cars
    travel
    simulation
    human being
    trend
    interaction

    Keywords

    • bus priority
    • pre-signal
    • signalized intersection
    • single-lane approaches

    ASJC Scopus subject areas

    • Transportation

    Cite this

    Providing bus priority at signalized intersections with single-lane approaches. / Guler, S. Ilgin; Gayah, Vikash V.; Menendez, Monica.

    In: Transportation Research Procedia, Vol. 9, 01.01.2015, p. 225-245.

    Research output: Contribution to journalArticle

    Guler, S. Ilgin ; Gayah, Vikash V. ; Menendez, Monica. / Providing bus priority at signalized intersections with single-lane approaches. In: Transportation Research Procedia. 2015 ; Vol. 9. pp. 225-245.
    @article{bf644626ce6f4aef8e79c9feccfae3ef,
    title = "Providing bus priority at signalized intersections with single-lane approaches",
    abstract = "Signalized intersections often represent a major source of bus delays. One typical strategy to mitigate this problem is to dedicate an existing car lane for bus-use only to minimize the interactions between cars and buses. However, this is physically impossible at approaches where only a single travel lane is available for each direction. To this end, this research explores a novel method to provide priority to buses at signalized intersections with single-lane approaches through the use of additional signals in a way that (nearly) eliminates bus delays while minimizing the negative impacts imparted to cars. Using these signals, the bus can jump a portion of the car queue using the travel lane in the opposite direction. This paper theoretically quantifies the delay savings buses can achieve, and the negative impacts imparted onto cars when this pre-signal strategy is applied. The negative impacts are measured as the additional car delays experienced when the intersection signal is under-saturated, and the reduction in car-discharge capacity when the intersection signal is over-saturated. In the under- saturated case, the results show that moderate average bus delay savings (∼5-7 seconds per vehicle) are achieved if the pre-signal is always in operation; and these results decrease the total system-wide delay (measured in person-hours) only if bus occupancies are very high. However, if the pre-signal operation is targeted to only provide priority to the buses that would benefit the most, significant bus delay savings can be achieved (delay benefits to buses which receive priority are about doubled) while also reducing the system-wide delay, even if the ratio of bus to car occupancy is relatively modest (greater than about 20). In the over-saturated case, bus delay savings can be much more significant than under-saturated cases (greater than 30 seconds per bus), and this delay saving can increase further for longer block lengths (greater than 100 m). However, the capacity of the intersection decreases by up to 25{\%} during each cycle in which a bus arrives to the intersection. Simulation tests confirmed that the general trends and magnitudes of bus delay savings and negative impacts to cars hold for more realistic behaviors. The overall benefits are slightly smaller in the simulations, but nevertheless the strategy seems promising as a bus priority strategy at intersections with single-lane approaches in the field.",
    keywords = "bus priority, pre-signal, signalized intersection, single-lane approaches",
    author = "Guler, {S. Ilgin} and Gayah, {Vikash V.} and Monica Menendez",
    year = "2015",
    month = "1",
    day = "1",
    doi = "10.1016/j.trpro.2015.07.013",
    language = "English (US)",
    volume = "9",
    pages = "225--245",
    journal = "Transportation Research Procedia",
    issn = "2352-1457",
    publisher = "Elsevier BV",

    }

    TY - JOUR

    T1 - Providing bus priority at signalized intersections with single-lane approaches

    AU - Guler, S. Ilgin

    AU - Gayah, Vikash V.

    AU - Menendez, Monica

    PY - 2015/1/1

    Y1 - 2015/1/1

    N2 - Signalized intersections often represent a major source of bus delays. One typical strategy to mitigate this problem is to dedicate an existing car lane for bus-use only to minimize the interactions between cars and buses. However, this is physically impossible at approaches where only a single travel lane is available for each direction. To this end, this research explores a novel method to provide priority to buses at signalized intersections with single-lane approaches through the use of additional signals in a way that (nearly) eliminates bus delays while minimizing the negative impacts imparted to cars. Using these signals, the bus can jump a portion of the car queue using the travel lane in the opposite direction. This paper theoretically quantifies the delay savings buses can achieve, and the negative impacts imparted onto cars when this pre-signal strategy is applied. The negative impacts are measured as the additional car delays experienced when the intersection signal is under-saturated, and the reduction in car-discharge capacity when the intersection signal is over-saturated. In the under- saturated case, the results show that moderate average bus delay savings (∼5-7 seconds per vehicle) are achieved if the pre-signal is always in operation; and these results decrease the total system-wide delay (measured in person-hours) only if bus occupancies are very high. However, if the pre-signal operation is targeted to only provide priority to the buses that would benefit the most, significant bus delay savings can be achieved (delay benefits to buses which receive priority are about doubled) while also reducing the system-wide delay, even if the ratio of bus to car occupancy is relatively modest (greater than about 20). In the over-saturated case, bus delay savings can be much more significant than under-saturated cases (greater than 30 seconds per bus), and this delay saving can increase further for longer block lengths (greater than 100 m). However, the capacity of the intersection decreases by up to 25% during each cycle in which a bus arrives to the intersection. Simulation tests confirmed that the general trends and magnitudes of bus delay savings and negative impacts to cars hold for more realistic behaviors. The overall benefits are slightly smaller in the simulations, but nevertheless the strategy seems promising as a bus priority strategy at intersections with single-lane approaches in the field.

    AB - Signalized intersections often represent a major source of bus delays. One typical strategy to mitigate this problem is to dedicate an existing car lane for bus-use only to minimize the interactions between cars and buses. However, this is physically impossible at approaches where only a single travel lane is available for each direction. To this end, this research explores a novel method to provide priority to buses at signalized intersections with single-lane approaches through the use of additional signals in a way that (nearly) eliminates bus delays while minimizing the negative impacts imparted to cars. Using these signals, the bus can jump a portion of the car queue using the travel lane in the opposite direction. This paper theoretically quantifies the delay savings buses can achieve, and the negative impacts imparted onto cars when this pre-signal strategy is applied. The negative impacts are measured as the additional car delays experienced when the intersection signal is under-saturated, and the reduction in car-discharge capacity when the intersection signal is over-saturated. In the under- saturated case, the results show that moderate average bus delay savings (∼5-7 seconds per vehicle) are achieved if the pre-signal is always in operation; and these results decrease the total system-wide delay (measured in person-hours) only if bus occupancies are very high. However, if the pre-signal operation is targeted to only provide priority to the buses that would benefit the most, significant bus delay savings can be achieved (delay benefits to buses which receive priority are about doubled) while also reducing the system-wide delay, even if the ratio of bus to car occupancy is relatively modest (greater than about 20). In the over-saturated case, bus delay savings can be much more significant than under-saturated cases (greater than 30 seconds per bus), and this delay saving can increase further for longer block lengths (greater than 100 m). However, the capacity of the intersection decreases by up to 25% during each cycle in which a bus arrives to the intersection. Simulation tests confirmed that the general trends and magnitudes of bus delay savings and negative impacts to cars hold for more realistic behaviors. The overall benefits are slightly smaller in the simulations, but nevertheless the strategy seems promising as a bus priority strategy at intersections with single-lane approaches in the field.

    KW - bus priority

    KW - pre-signal

    KW - signalized intersection

    KW - single-lane approaches

    UR - http://www.scopus.com/inward/record.url?scp=84983182116&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=84983182116&partnerID=8YFLogxK

    U2 - 10.1016/j.trpro.2015.07.013

    DO - 10.1016/j.trpro.2015.07.013

    M3 - Article

    VL - 9

    SP - 225

    EP - 245

    JO - Transportation Research Procedia

    JF - Transportation Research Procedia

    SN - 2352-1457

    ER -