American Association of
State Highway and Transportation Officials
Special Committee on
Research and Innovation
FY2023 NCHRP PROBLEM
STATEMENT TEMPLATE
Problem Number:
2023-G-31
Problem Title
Incorporating
a methodology for planning and operational analysis of freeway facilities with
ramp meeting strategy.
Background Information and Need For Research
Ramp
metering is an efficient Active Traffic Management (ATM) strategy (Federal
Highway Administration, 2020). Ramp meters are signals that control the on-ramp
to freeway traffic volumes. The strategy is aimed at ameliorating the potential
for traffic jams by not only regulating the on-ramp flow but also fragmenting
vehicle platoons entering the freeway. This is a cost-effective solution
compared to upgrading the traditional freeway's capacity. Ramp metering also offers
safety benefits. The strategy is widely implemented by agencies across the
nation. It was reported that ramp meters led to a rise in travel speed, a
decrease in travel time, a decrease in crash experience, and a lessening of
vehicular emissions in multiple large cities. They are Minneapolis/St Paul,
Long Island, Portland, Denver, and Seattle (Federal Highway Administration,
2020).
The HCM
6th Edition's methodologies for freeway facilities can be used to model ramp
meters; however, the lack of calibration (e.g., capacity gain at the merge
points) along with practitioner-ready guidance makes it difficult to be
utilized. Another significant shortcoming is the impact of ramp meters on the
upstream interchange. This results in a significant bias for estimating this
ATM strategy to alleviate unfavorable traffic conditions in our roadway
corridors. While the types of ramp metering systems/algorithms abound, the
travel time is curtailed even when accounting for on-ramp queued vehicles
(Federal Highway Administration, 2020). When it comes to the use of
traffic-responsive ramp meters, the travel time reliability method in the HCM
should be considered to provide traffic demand fluctuations for estimating
benefits. As of today, this cannot be achieved in the HCM framework. With that,
multiple jurisdictions witnessed an improvement in travel time reliability as a
result of implementing ramp meters. In the absence of ramp metering, the
on-ramp traffic may prompt freeway mainline drivers to reduce speed or shift to
the left lane to permit the entrance of the on-ramp vehicles. This reduction in
the travel speed of the freeway mainline traffic may possibly give rise to
clogging. With ramp meters in place, the control of the on-ramp vehicles
merging onto the mainline mitigate such effects. The meters also decrease
traffic occupancy, a surrogate measure of traffic density, and the time to
recuperate from oversaturated conditions to undersaturated conditions. In
addition, with ramp meters implemented at multiple on-ramps along a freeway
facility, an area-wide strategy may be executed to enhance traffic flow
efficiency throughout the facility as a whole (Federal Highway Administration,
2020). Hence, incorporating the impacts of ramp metering in the HCM's freeway
facilities/reliability, as well as merge and weaving segments' chapters, is
merited.
Reference
Federal
Highway Administration, 2020. Ramp Metering: A Proven, Cost-Effective
Operational Strategy—A Primer. Federal Highway Administration, U.S. Department
of Transportation, Washington, D.C.
https://ops.fhwa.dot.gov/publications/fhwahop14020/sec1.htm.
LITERATURE
SEARCH SUMMARY
The
traffic engineering literature is rich with reports and scientific
peer-reviewed articles on ramp metering. In particular, the publications pertain
to the operational, safety and economic benefits of implementing ramp metering
systems. Following are relevant references:
Aghdashi,
S., Davis, J., Chase, T., Cunningham, C., 2020. Modeling and Validating Traffic
Responsive Ramp Metering in the Highway Capacity Manual Context. Transportation
Research Record: Journal of the Transportation Research Board 2674 (12),
91-102. https://doi.org/10.1177/0361198120949533.
Asgharzadeh,
M., Kondyli, A., 2020. Effect of Geometry and Control on the Probability of Breakdown
and Capacity at Freeway Merges. American Society of Civil Engineers Journal of
Transportation Engineering, Part A: Systems 146 (7), 04020055.
https://doi.org/10.1061/JTEPBS.0000381.
Chang,
G.-L., Cheng, Y., Chen, Y.-Y., Chen, Y.-H., 2020. Integration of Ramp Metering
and Off-Ramp Progression. Report Number MD-20-SHA/UM/5-14. Maryland Department
of Transportation, Baltimore, Maryland.
Cheng,
Y., Chang, G.-L., 2021. Arterial-Friendly Local Ramp Metering Control Strategy.
Transportation Research Record: Journal of the Transportation Research Board
2675 (7), 67-80. https://doi.org/10.1177/0361198121994581.
Cho, H.,
Chilukuri, B., Laval, J., Guin, A., Suh, W., Ko., J., 2020. Genetic Algorithm-Based
Simulation Optimization of the ALINEA Ramp Metering System: A Case Study in
Atlanta. Transportation Planning and Technology 43 (5), 475-487.
https://doi.org/10.1080/03081060.2020.1763655.
Cho, H.,
Laval, J., 2020. Combined Ramp-Metering and Variable Speed Limit System for
Capacity Drop Control at Merge Bottlenecks. American Society of Civil Engineers
Journal of Transportation Engineering, Part A: Systems 146 (6), 04020033.
https://doi.org/10.1061/JTEPBS.0000350.
Frejo, J., De Schutter, B., 2021. Logic-Based Traffic
Flow Control for Ramp Metering and Variable Speed Limits—Part 1: Controller.
Institute of Electrical and Electronics Engineers Transactions on Intelligent
Transportation Systems 22 (5), 2647-2657. https://doi.org/10.1109/TITS.2020.2973717.
Frejo, J., De Schutter, B., 2021. Logic-Based Traffic
Flow Control for Ramp Metering and Variable Speed Limits—Part 2: Simulation and
Comparison. Institute of Electrical and Electronics Engineers Transactions on
Intelligent Transportation Systems 22 (5), 2658-2668.
https://doi.org/10.1109/TITS.2020.2973732.
Haule, H., Ali, M., Alluri, P., Sando, T., 2021. Evaluating the Effect
of Ramp Metering on Freeway Safety Using Real-Time Traffic Data. Accident
Analysis & Prevention 157, 106181. https://doi.org/10.1016/j.aap.2021.106181.
Heshami,
S., Kattan, L., 2021. Ramp Metering Control under Stochastic Capacity in a
Connected Environment: A Dynamic Bargaining Game Theory Approach.
Transportation Research Part C: Emerging Technologies 130, 103282. https://doi.org/10.1016/j.trc.2021.103282.
Jacobson,
L., Stribiak, J., Nelson, L., Sallman, D., 2006. Ramp Management and Control
Handbook. FHWA-HOP-06-001. U.S. Department of Transportation, Washington, D.C.
Kotsialos,
A., 2021. A Varying Parameter Multi-Class Second-Order Macroscopic Traffic Flow
Model for Coordinated Ramp Metering with Global and Local Environmental
Objectives. Transportation Research Part C: Emerging Technologies 128, 103106.
https://doi.org/10.1016/j.trc.2021.103106.
Laval,
J., Xu, T., 2020. Implementation of a Variable Speed Limit/Ramp Metering
Strategy to Increase Freeway Capacity at Metered On-Ramps. Report Number
FHWA-GA-20-1826. Georgia Department of Transportation, Atlanta, Georgia.
Ma, M., Liang, S., Zhang, H., 2020. A Dynamic Competition
Control Strategy for Freeway Merging Region Balancing Individual Behaviour and
Traffic Efficiency. Promet – Traffic & Transportation 32 (5), 595-609.
https://doi.org/10.7307/ptt.v32i5.3367.
Mauch,
M., Skabardonis, A., 2021. Evaluation of Coordinated Ramp Metering (CRM)
Systems in California. University of California (UC) Berkeley California
Partners for Advanced Transportation Technology (PATH) Report
UCB-ITS-RR-2020-02. UC Berkeley, Berkeley, California.
Mizuta,
A., Roberts, K., Jacobsen, L., Thompson, N., 2014. Ramp Metering: A Proven,
Cost-Effective Operational Strategy – A Primer. FHWA-HOP-14-020. U.S.
Department of Transportation, Washington, D.C.
Pang, M.,
Yang, M., 2020. Coordinated Control of Urban Expressway Integrating Adjacent
Signalized Intersections Based on Pinning Synchronization of Complex Networks.
Transportation Research Part C: Emerging Technologies 116, 102645.
https://doi.org/10.1016/j.trc.2020.102645.
Reinolsmann,
N., Alhajyaseen, W., Bris, T., Pirdavani, A., Hussain, Q., Bris, K., 2021.
Investigating the Impact of a Novel Active Gap Metering Signalization Strategy
on Driver Behavior at Highway Merging Sections. Transportation Research Part F:
Traffic Psychology and Behaviour 78, 42-57.
https://doi.org/10.1016/j.trf.2021.01.017.
Wang, Y.,
2021. Freeway Traffic Control in Presence of Capacity Drop. Institute of
Electrical and Electronics Engineers Transactions on Intelligent Transportation
Systems 22 (3), 1497-1516. https://doi.org/10.1109/TITS.2020.2971663.
Xu, Z., Zou, X., Oh, T., Vu, H., 2021. Studying Freeway
Merging Conflicts Using Virtual Reality Technology. Journal of Safety Research
76, 16-29. https://doi.org/10.1016/j.jsr.2020.11.002.
Yang, G.,
Wang, Z., Tian, Z., Zhao, L., Xu, H., 2020. Geometric Design of Metered
On-Ramps: State-of-the-Practice and Remaining Challenges. Transportation
Letters 12 (9), 649-658. https://doi.org/10.1080/19427867.2019.1677067.
Zhou, Y.,
Ozbay, K., Kachroo, P., Zuo, F., 2020. Ramp Metering for a Distant Downstream
Bottleneck Using Reinforcement Learning with Value Function Approximation.
Journal of Advanced Transportation. https://doi.org/10.1155/2020/8813467.
Research Objective
There is
a pressing requirement to integrate ramp metering effects into the HCM's
methodologies pertaining to freeway segments and freeway facilities and
reliability methodologies. With ramp metering systems' operational and safety
benefits, traffic flow performance measures, including the user delay costs and
travel time reliability, are expected to be improved. In summary, the main
objectives of this Research Needs Statement (RNS) are:
• Enable a traffic responsive method to
evaluate the impact of ramp meters to demonstrate better its influence in
improving the travel time reliability and user delay cost.
• With the addition of methods to
measure the impact of on-ramp queue (as a result of metering) backing into an
upstream intersection, we can better estimate the value of ramp meters
• The safety benefits of ramp meters
will enable agencies to better decide on moving ahead with their ramp meter
implementation projects
• By measuring the mobility and safety
benefits of ramp meters, HCM can provide a solid foundation to estimate the
benefit to cost (B/C) analysis for decision-makers.
The
following tasks are proposed to accomplish the objective:
Task 1:
Literature Review
Conduct
an exhaustive literature review on the operational and safety benefits of the
various types of ramp metering systems. This includes the various ramp metering
algorithms impacts on the performance measures and how those impacts may be
incorporated into the HCM's chapters (i.e., freeway facilities, reliability,
merge and weaving segments, and Active Traffic and Demand Management (ATDM)
chapters). Moreover, this task will document different use cases of ramp
metering analyses at the planning and operation levels.
Task 2:
Draft Methodology and Data Collection Plan
Identify
the required data to be collected to assess the impacts of ramp metering
algorithms on traffic flow parameters. Also, elaborate on the data sources and
method of assessing such impacts, whether analytically or via traffic
microsimulation models. The data to be collected should include traffic
conditions on the freeway merge point, ramp roadway, and upstream intersection.
The plan should also propose ways to collect data in the absence of access to
the field (e.g., simulation)
Task 3:
Methodology Development
Propose a
set of methods to:
• Enable planning level analysis of
ramp meters. This includes a set of capacity (and speed) adjustment factors
that can be inputted into a single segment (e.g., merger and weave) and freeway
facilities analyses. These default capacity adjustment values can also be used
to plan for future facilities or long-term improvement projects.
• Enable an operational level analysis
to assist agencies in modeling their traffic responsive ramp meters and tune
their parameters to achieve optimal operations. This operational level
methodology should be incorporated into the oversaturated freeway facilities
methodology to enable its use in the travel time reliability analysis.
Task 4:
Data Collection and Model Validation
Collect
the relevant data identified in Task 2. Evaluate the effects of ramp meters on
operations via the approaches selected in Task 2. Validate the developed
methodologies using field data.
Task 5:
Update the HCM
Update
all relevant HCM chapters and provide computational engines that perform the
proposed methodologies' tasks.
Urgency and Potential Benefits
Substantial.
This research effort will give rise to state-of-the-practice procedural
methodologies for the HCM. It will overcome the shortcomings of the current
HCM, which does not incorporate ramp metering effects into the freeway
facilities, reliability, merge segments, and weaving segments' methodologies.
Failure to fund this problem statement will result in the cost-prohibitive use
of microsimulation methods.
Implementation Considerations
Since
this effort will culminate in updated HCM methodologies, the target audience
includes transportation engineering professionals and academic instructors.
Recommended Research Funding and Research
Period
Research
Funding: $500,000
Research
Period: 36 months
Problem Statement Author(S): For each author,
provide their name, affiliation, email address and phone.
Ahmed
Farid, Ph.D., California Polytechnic State University, (407) 530-9360, farid@calpoly.edu
Shams
Tanvir, Ph.D., California Polytechnic State University, (805) 756-2947,
stanvir@calpoly.edu
Alexandra
Kondyli, Ph.D., University of Kansas, (785) 864-6521, akondyli@ku.edu
Behzad
Aghdashi, Ph.D., McTrans Center @ University of Florida, (352) 294 3095,
saghdashi@ufl.edu
Potential Panel Members: For each panel
member, provide their name, affiliation, email address and phone.
Person Submitting The Problem Statement: Name, affiliation,
email address and phone.
Brian G.
Dunn, PE Oregon DOT, brian..dunn@odot.state.or.us, 503-507-8013
Brenton
Bogard, P.E., Ohio DOT, 614-752-5575 (supporting this RNS)