Ramp Metering:

A Proven Effective Strategy

WHAT IS RAMP METERING?

Ramp metering is a strategy used to regulate 

the volume of vehicles entering a freeway 

at a given time thereby seeking optimal 

freeway operations. Access to the freeway 

is controlled using a traffic signal that is 

powered by an algorithm that uses real-time 

system traffic data to determine the rate at 

which vehicles should enter the freeway. This 

breaks up the platoons of vehicles attempting 

to merge onto the mainline. Vehicles already 

on the mainline will not need to reduce their 

speed as much due to the spacing of the 

entering vehicles. 

Rather than acting in isolation, ramp 

metering is an integral part of an agency’s 

overall corridor management and operations 

program. Agencies can align ramp metering 

programs with programs or efforts, such as 

arterial management, incident management, 

work zone management, integrated corridor 

management or with others, to optimize the 

combined effect of their tools and strategies. 

Coordinating these programs and deploying 

ramp metering will likely depend on the 

capabilities of the agencies involved.

San Diego

Seattle

Los Angeles

Sacramento

New York Chicago

Dallas–Ft. Worth

Philadelphia

Washington, D.C.

Houston

Miami

Atlanta

Boston

San Francisco

Bay Area

Detroit

Grand

Rapids

Riverside–

San Bernardino

Phoenix

Minneapolis–

St. Paul

St. Louis

Tampa

Baltimore Pittsburgh 

Portland

Charlotte

Austin

Orlando

Jacksonville

Cincinnati

Cleveland

Las Vegas

Columbus

Virginia Beach

Nashville

Memphis

Providence

Oklahoma City

Louisville Richmond

New Orleans

Raleigh

Salt Lake City

Rochester Buffalo

Denver

Milwaukee

Indianapolis

San Antonio

Birmingham

Hartford

Kansas City

More than 300 ramp meters

101–300 ramp meters

1–100 ramp meters

No ramp metering

Ramp Meter Penetration Ramp Meter Control

Local or Fixed-Time Control: Meters are either 

fixed/pre-timed to meet historical trends or are 

responsive/actuated to meet local, real-time conditions 

in the vicinity of the ramp. 

System Control: Meters are responsive/actuated to 

system-wide conditions (i.e., optimizing flow along an 

entire facility, corridor, or system wide). 

Note: 1. According to the 2010 United States Census, metro areas have a population greater than one million people. 

 2. Ramp metering information is current as of 2014.

RAMP METERING IN THE TOP U.S. METROPOLITAN AREAS1, 2

Traffic Speed Increase

Travel Time Reduction

Collision Reduction

Emission Reduction

LEGEND

0%

20%

40%

60%

80%

100%

Long Island

0%

20%

40%

60%

80%

100%

Minneapolis/ St. Paul

0%

20%

40%

60%

80%

100%

Seattle

0%

20%

40%

60%

80%

100%

Denver

0%

20%

40%

60%

80%

100%

120%

140%

160%

180%

200%

Portland

SEPTEMBER 2014

BENEFITS OF 

RAMP METERING

Ramp metering is a widely 

proven, cost-effective strategy 

to increase the efficiency 

of a freeway system. Metro 

areas that deployed ramp 

meters touted benefits such as 

increases in freeway mainline 

throughput, decreases in overall 

travel delays, increases in 

travel time reliability, reductions 

in freeway crashes and their 

severity, and even benefits 

to the environment through 

reductions in fuel consumption 

and emissions.

BENEFITS IN SELECTED CITIES

FHWA-HOP-14-021
KEYS FOR SUCCESSFUL DEPLOYMENT, 

OPERATION, AND EXPANSION 

Whether an agency is expanding their already robust system, or 

deploying ramp meters for the first time, there are key components 

at each of the planning, implementation, and operations stages that 

agencies should keep in mind.

Ramp Metering: A Proven Effective Strategy

GETTING READY FOR RAMP METERING

After affirming the feasibility of ramp metering, agencies should 

plan for implementation based on regional policy and recommended 

outcomes from feasibility studies. This also includes assessing 

staffing needs, organizational capabilities, and agency readiness 

as well as planning for data collection, funding procurement, and 

equipment testing.

IS RAMP METERING RIGHT FOR YOU?

Ramp metering should be deployed with the purpose of addressing 

existing operational issues. The primary issue mitigated by ramp 

metering is recurring mainline congestion, however agencies 

may also want to increase safety and control mainline access, 

especially during construction activities, special events, or traffic 

incidents. All of these issues have the potential to be aided through 

ramp metering, but if they are not present in the region or corridor, 

ramp metering is likely not an applicable strategy and should not 

be pursued.

CASE STUDY

The Twin Cities evaluated the costs and benefits of their ramp metering system, which 

provided the agency with empirical basis for the expenses associated with ramp metering. 

The evaluation yielded a benefit/cost ratio of 15 to 1, thus the benefits of ramp metering 

dramatically outweighed its costs.

BENEFIT/COST ANALYSIS TOOLS

U.S. Department of Transportation Research & Innovative Technology 

Administration ITS Joint Programs Office Knowledge Resources: Users can 

browse benefits and costs of various projects.

FHWA Tool for Operations Benefit Cost Analysis (TOPS-BC): Users can select 

different project aspects and parameters to test the affect on total cost. 

GENERAL TIMELINE FOR PUBLIC OUTREACH PRIOR TO INITIAL DEPLOYMENT

For the initial implementation of ramp metering in a region, the public involvement plan 

should start three to five years prior to ramp meter activation and continues through one 

year after turn-on, with multiple objectives like increasing driver education and acceptance, 

addressing enforcement issues, and allowing for design changes prior to construction per 

public feedback. In the six months prior to metering, the agency should keep communities 

and agencies informed by holding public meetings and distributing flyers.

GAIN PUBLIC/AGENCY SUPPORT

Agencies should devote substantial effort to outreach and collaboration. First, 

the agency should partner with other relevant agencies to gain concurrence and 

support. For both agencies and the public, one of the best ways to encourage 

support is by proactively disseminating information and clearly communicating 

the benefits of ramp metering. This may include gathering public feedback, 

conducting open houses, and issuing statements to local media. In order 

to reach a broader local population, the agency should maintain important 

information on a web site and distribute it via brochure or flyer. Providing 

clear information and addressing questions adds transparency to the planning 

process, which the public will generally favor.

IDENTIFY COST & SECURE FUNDING SOURCES

Agencies can utilize FHWA resources and tools to identify capital and operating 

costs related to the installation of new systems. Agencies can strengthen their 

case for deploying ramp metering by itemizing specific costs, thus increasing 

transparency. Providing benefit/cost information can help strengthen the 

case for ramp meter expansion by showcasing the benefits and providing 

leverage for requesting funds. In order to secure funding, agencies must also 

communicate the high priority of ramp metering to authorities.

CASE STUDIES

Miami faced public opposition during their efforts to deploy ramp metering. Through 

outreach and educational efforts, the agency was able to shift public opinion and raise the 

support required to start metering.

New York City ran a public relations campaign to re-brand ramp meters as “merge lights” as 

a means of circumventing pre-existing negative perceptions about ramp metering.

Are you experiencing these challenges?

- Mainline congestion - Safety issues at merge points

- Safey issues on the mainline - Construction impacts

- Special event impacts

Ramp meter 

may not be 

a suitable 

option

Needs can be addressed by ramp metering

Is ramp metering feasible?

- Conduct feasibility studies - Conduct benefit/cost analysis

- Evaluate feasibility outcomes 

- Assess agency capability and maturity

NO

YES

Ramp meter 

may not be 

a suitable 

option

NO

YES

Knowledge of agency and regional policies and priorities

Q1

Q2

Prepare for ramp meter deployment

- Plans should align with regional goals & objectives

- Conduct systems engineering

COMMON CHALLENGES

These challenges were gathered from a 2014 survey of agencies in the top 

metropolitan areas in the United States. The percentages refer to the share 

of survey respondents who faced a particular challenge during attempts to 

deploy ramp meters.

FEASIBILITY STUDIES & BENEFIT/COST ANALYSIS

Agencies should conduct feasibility studies and benefit/cost analysis on 

proposed ramp metering locations. Benefit/cost analysis monetizes the 

estimated benefits of ramp metering associated with travel time, crash 

reduction, and emissions reduction savings and compare against estimated 

capital and operations and maintenance costs.

SEPTEMBER 2014
“ Our region first installed ramp metering in our 

state’s largest urban area in the 1980’s and we have 

steadily expanded the system since then. Other, 

smaller cities in our state have seen the benefits 

and are planning ramp meter systems.”

– Pete Briglia, former WSDOT and TRB Freeway 

Operations Committee Chair

OPERATING RAMP METERS EFFECTIVELY

After turning on the ramp meters, agencies should determine their 

impact on operations, identify areas of improvement, and continue 

building inter-agency and public support. By building a robust 

performance assessment process, agencies can learn about their 

current system and whether it should be expanded.

PERFORMANCE MEASUREMENT & REPORTING

Agencies should establish which performance metrics to measure, 

appropriate benchmarks for those measures, monitoring procedures, and 

reporting procedures. Dimensions of performance metrics to measure can 

include safety, mobility, public acceptance, travel time reliability, facility 

throughput, and environmental impacts.

Measuring the costs and benefits of a proposed ramp metering system is 

a practiced strategy for accelerating ramp metering deployment. Agencies 

could face scrutiny regarding the proposed benefits of ramp metering in their 

regions. As discussed, a cost/benefit analysis can make the case for ramp 

metering more convincing. 

Agencies should give particular attention to the length and behavior of the 

ramp queues and establish policies and methods for regularly monitoring 

the ramp queues, as traffic conditions can change overtime and throughout 

the day.

THINKING ABOUT EXPANSION?

Agencies considering expansion or further development of their ramp 

metering program should first assess the current state of the program. In 

particular, the agencies should evaluate current performance metrics in 

order to target areas of opportunity and set expectations for improvement. 

The impact of the proposed expansion should be reported and shared with 

relevant stakeholders.

In a 2014 FHWA survey of the top metro areas, there was a high level of 

interest in expansion amongst areas that had already deployed ramp meters.

Maybe

21%

Yes

68%

No

11%

Question: Are there 

plans to expand your 

ramp meter system in 

the next 1 to 5 years?

MAINLINE

ARTERIAL

ON-RAMP

ON-RAMP

CASE STUDY

San Diego had insufficient storage on 

many of its ramps, but the local agency 

collaborated with agencies responsible 

for arterial signals to reduce the impact of 

long queues on arterial traffic.

UNDERSTAND TRAFFIC CONDITIONS 

The agency should study pre-metering traffic conditions of the corridor. The 

current and anticipated mainline volumes, ramp volumes, and surrounding 

arterial volumes should be evaluated in regards to how they will be impacted by 

ramp metering. The capacity of the ramps will likely influence the other aspects 

of the ramp meter operations.

MANAGE QUEUES & DELAYS

Queue management is crucial for optimizing freeway operations, and long 

queues generally contribute to negative public perception. Queue management 

is closely related to the geometric limitations of the existing ramps, so both 

could be considered when exploring options.

Ramp metering technology has developed various methods of queue detection 

and corresponding solutions, such as being hard-wired into the controller or 

with the software as a function of the control algorithm. If adding storage 

capacity at a ramp is not feasible, an agency could consider adjusting the 

metering control scheme to increase ramp metering capacity. 

Agencies should create policies on maximum queue wait time, and be able to 

communicate and justify these policies publicly.

Dual lane metering © Robert Couse Baker via Flickr

58% Existing Ramp Geometry

42% Cost/Funding

33% Public Opposition

25% Heavy Ramp Volume

17% Local Agency Opposition

17% Lack of Agency Resources

Two cars per green

MNDOT POLICY

“...onto adjacent arterials by keeping 

local ramp wait times to under 4 minutes. 

Freeway-to-freeway ramp wait times are 

kept under 2 minutes.”

SOURCE: MnDOT
Ramp Metering: A Proven Effective Strategy

RESOURCES FOR MORE INFORMATION

FHWA Ramp Management web site 

http://www.ops.fhwa.dot.gov/freewaymgmt/ramp_mgmnt.htm 

FHWA Office of Operations web site 

http://www.ops.fhwa.dot.gov/ 

FHWA Operations Benefit/Cost Analysis Desk Reference web site 

http://ops.fhwa.dot.gov/publications/fhwahop13004/

U.S. Department of Transportation Research & Innovative Technology 

Administration ITS Joint Programs Office Knowledge Resources 

web site (including benefit and cost databases) 

http://www.itsknowledgeresources.its.dot.gov/

FHWA Ramp Management and Control Handbook 

http://ops.fhwa.dot.gov/publications/ramp_mgmt_handbook/manual/manual/pdf/

rm_handbook.pdf

Ramp Metering Public Outreach videos

Maximizing the Flow (Source: Kansas City Scout)

http://www.kcscout.net/RMWatchTheVideo.aspx

Ramp Metering: Signal for Success (Source: FHWA)

https://www.youtube.com/watch?v=rsvaGXW6moA

Ramp Meters: How-to (Source: RTC of Southern Nevada)

https://www.youtube.com/watch?v=Lv3CHhsPN-Y) 

To obtain more information on ramp metering, 

please contact:

FHWA Office of Operations

operationsfeedback@dot.gov

© Thomanication via Flickr

“ Ramp meters are the most

effective traffic management 

strategy available. They 

have consistently shown 

high levels of benefits 

across numerous 

deployments throughout 

the U.S.”

– Brian Kary

Freeway Operations Engineer, 

Minnesota DOT

SEPTEMBER 2014

GOING ABOVE AND BEYOND

One of the key attitudes that agencies with successful ramp 

metering programs embrace is the desire for continued 

improvement in ramp metering operations. Through ongoing 

performance monitoring and internal agency assessment, 

enhanced ramp metering strategies can be identified and 

planned for in future regional planning efforts. Even agencies 

that already have ramp meters should assess both suitability and 

feasibility prior to expanding and improving their program. These 

approaches tend to require high organizational capability and are 

not necessarily suitable for all ramp metering locations.

Operational enhancements can include: 

• Extended Hours of Operation

Policies that extend ramp meter operations outside the peak 

hours and for special events and construction activities offer 

further flexibility and control. 

• Special Ramp Treatments

This encompasses strategies that can improve traffic 

conditions, improve safety at the merge point, and provide 

driver incentives for specific modes of travel. For instance, an 

agency could designate a bypass lane accessible only to HOVs 

or transit vehicles. 

• Adaptive Ramp Metering

Adaptive ramp metering utilizes algorithms that can optimize 

either local or system-wide conditions. Adaptive ramp 

metering can also utilize advanced metering technologies 

such as dynamic bottleneck identification, automated incident 

detection, and integration with adjacent arterial traffic signal 

operations. This technique is effective for recurring and nonrecurring congestion.

• Integrated Freeway and Arterial Corridor

When operating independently of the ramp meter signals, 

the arterial signals may release too many cars onto the ramp, 

causing backup onto the arterial. If the two systems are 

integrated, backup could be reduced leading to safer and more 

efficient conditions.