Increasing the capacity of an isolated merge by metering its on-ramp
Measurements taken downstream of freeway/on-ramp merges have previously shown that discharge flow diminishes when a merge becomes an isolated bottleneck. By means of observation and experiment, we show here that metering an on-ramp can recover the higher discharge flow at a merge and thereby increase the merge capacity. Detailed observations were collected at a single merge using video. These data revealed that the reductions in discharge flow are triggered by a queue that forms near the merge in the freeway shoulder lane and then spreads laterally, as drivers change lanes to maneuver around slow traffic. Our experiments show that once restrictive metering mitigated this shoulder lane queue, high outflows often returned to the median lane. High merge outflows could be restored in all freeway lanes by then relaxing the metering rate so that inflows from the on-ramp increased. Although outflows recovered in this fashion were not sustained for periods greater than 13Â min, the findings are the first real evidence that ramp metering can favorably affect the capacity of an isolated merge. Furthermore, these findings point to control strategies that might generate higher outflows for more prolonged periods and increase merge capacity even more. Finally, the findings uncover details of merge operation that are essential for developing realistic theories of merging traffic.
If you experience problems downloading a file, check if you have the proper application to view it first. In case of further problems read the IDEAS help page. Note that these files are not on the IDEAS site. Please be patient as the files may be large.
As the access to this document is restricted, you may want to look for a different version under "Related research" (further below) or search for a different version of it.
Volume (Year): 39 (2005)
Issue (Month): 10 (December)
|Contact details of provider:|| Web page: http://www.elsevier.com/wps/find/journaldescription.cws_home/548/description#description|
|Order Information:|| Postal: http://www.elsevier.com/wps/find/supportfaq.cws_home/regional|
References listed on IDEAS
Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.:
- Muñoz, Juan Carlos & Daganzo, Carlos F., 2002. "The bottleneck mechanism of a freeway diverge," Transportation Research Part A: Policy and Practice, Elsevier, vol. 36(6), pages 483-505, July.
- Daganzo, Carlos F., 1995. "The cell transmission model, part II: Network traffic," Transportation Research Part B: Methodological, Elsevier, vol. 29(2), pages 79-93, April.
- Cassidy, Michael J. & Anani, Shadi B. & Haigwood, John M., 2002. "Study of freeway traffic near an off-ramp," Transportation Research Part A: Policy and Practice, Elsevier, vol. 36(6), pages 563-572, July.
- Cassidy, Michael J. & Bertini, Robert L., 1999. "Some traffic features at freeway bottlenecks," Transportation Research Part B: Methodological, Elsevier, vol. 33(1), pages 25-42, February.
- Haj-Salem, Habib & Papageorgiou, Marcos, 1995. "Ramp metering impact on urban corridor traffic: Field results," Transportation Research Part A: Policy and Practice, Elsevier, vol. 29(4), pages 303-319, July.
- Daganzo, Carlos F. & Laval, Jorge & Munoz, Juan Carlos, 2002. "Ten Strategies for Freeway Congestion Mitigation with Advanced Technologies," Institute of Transportation Studies, Research Reports, Working Papers, Proceedings qt4kd6v6qf, Institute of Transportation Studies, UC Berkeley.
- Munoz, Juan Carlos & Daganzo, Carlos F, 2002. "Fingerprinting Traffic From Static Freeway Sensors," University of California Transportation Center, Working Papers qt1mf4n2w8, University of California Transportation Center.
When requesting a correction, please mention this item's handle: RePEc:eee:transb:v:39:y:2005:i:10:p:896-913. See general information about how to correct material in RePEc.
For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (Zhang, Lei)
If references are entirely missing, you can add them using this form.