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.:
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
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 you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.
If references are entirely missing, you can add them using this form.
If the full references list an item that is present in RePEc, but the system did not link to it, you can help with this form.
If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your profile, as there may be some citations waiting for confirmation.
Please note that corrections may take a couple of weeks to filter through the various RePEc services.