Chapter 7 – Ramp Management
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7.3 IMPLEMENTATION AND OPERATIONAL CONSIDERATIONS
Ramp management strategy implementation is a delicate process that begins well before strategies are physically deployed, and concludes only when deployed strategies have been successfully tested and initially operated. Before ramp management strategy implementation is seriously considered and systems or equipment are purchased, practitioners must coordinate internally with upper management to determine the feasibility of and support for ramp management strategy implementation. This includes close examination of the minimum requirements to successfully deploy and operate ramp management strategies, such as staffing levels and needs, hardware and software needs, budgetary constraints and resources, and policy directives.
7.3.1 Intra-Agency Readiness
Agencies preparing to implement ramp management strategies should take steps to ensure that strategies can be implemented successfully. Ramp management strategies should not be implemented until agencies are ready to implement, operate, and maintain selected strategies. Implementing the selected strategies requires planning to ensure that the needs of the agency and the public will be met. Keys aspects of this effort include:
- Systems Implementation – Ramp meter instrumentation (loops, signals, signs, controllers, etc.) need to be installed well in advance of when ramp metering is slated to begin.
- Software Implementation - Software that is used to establish communications in the field and that allow operators to monitor and control systems need to be developed or procured and tested before implementation can take place.
- Data Collection – Before ramp management strategies are implemented data need to be collected to evaluate the performance of ramp management strategies in delivering pre-determined goals and objectives. Traffic volumes, travel times, and other appropriate performance measures should be collected, modeled, and analyzed to estimate the benefits of implementing the ramp management strategy. Improvements to travel time and travel speeds in a specific corridor, as well as changes in congestion on the mainline and ramps, may be measures of effectiveness that can be used to prioritize locations where equipment will be installed. Depending on the scope of ramp management deployment, this action may need to be completed as much as one year in advance of when the strategy is slated to begin.
- Testing - It is critical to make sure all detection, communication, field controller firmware, and central system software is well tested before ramp meters are turned on. Ramp meters and associated equipment need to be installed well in advance of when strategies are slated to take effect. This gives parties responsible for ramp meter implementation time after meters are deployed but before meters are turned on to test each meter to confirm they are working properly.
- Staffing - New staff may need to be hired, or existing staff may need to be trained, when ramp management and control activities are added to a traffic management program. Staff may be needed to plan, design, operate or maintain strategies. Practitioners must determine the impacts that ramp management activities have on existing staff levels, and must assess how staffing needs will be filled. Practitioners must also assess the effect that changes to staffing have on current funding allocations. This is often overlooked during the planning stage, yet can be costly if training new staff is required or inadequate training is provided. Contractors may be hired on a full-time or part-time basis to satisfy or supplement staffing needs ( 1 ).
- Training - Systems and devices that support ramp management strategies can only be used to their furthest extent if staff are properly trained on how to operate and maintain them. All operators or maintenance staff responsible, whether existing or newly hired, will need to be trained on the procedures specific to individual systems and devices, operational policies, and testing and calibration methods. This includes typical and disaster specific emergency procedures.
7.3.2 Public Information and Outreach
Public information and outreach is needed to build consensus and understanding of the ramp management program and its associated activities. Public information and outreach is also critical from the stand point of acquiring public input so that strategies adequately address needs. Without a public information and outreach campaign motorists may not understand the ramp management strategies that have been implemented, and may not know how to properly respond to them. This may result in confusion or even contempt for ramp management strategies.
The size and scope of the public outreach effort should be commensurate with the size and scope of the ramp management strategy being implemented. Information released to the public, local agencies, and the media should be fair and accurate, to reduce the chance that the reliability of released information will be called into question at a later date. Information can be disseminated to the public, neighborhood groups and local agencies through brochures like the one shown in Figure 7-7, public information meetings, handouts, and/or print and electronic media.
- Local Leaders - Local leaders can be valuable advocates of or powerful opponents to ramp management strategies. Practitioners responsible for ramp management should determine whether local leaders are predisposed to either advocacy or opposition to the proposed strategies, and to develop an outreach program that targets both the advocates and the opponents.
- Motorists - Motorists’ initial impressions of ramp management strategies may be negative because negative aspects associated with these strategies are more easily observed than their benefits. For example, motorists may tend to focus on the fact that ramps that were once unrestricted, now have meters installed that delay their trips. Motorists often fail to understand that the negative aspects are usually more than completely offset by the improvements to mainline speed, delay, and safety. Therefore, public information campaigns should emphasize how strategies work, the reasons why strategies are being considered, and the benefits likely to be observed. By doing so, motorists’ negative perceptions of ramp management strategies may be mitigated to a greater extent.
7.3.3 Agency Agreements, Policies and Procedures
Intra- and inter-agency agreements, policies and procedures either need to be created or reviewed to determine if the ramp management strategies are supported, and if they are supported to dictate how strategies can then be implemented. An assessment of local, county, state and federal laws, regulations, and policies should be reviewed to determine if additional policies are needed and to assure that the planned strategies fit within the existing legal and policy framework for the local area. Agency agreements, policies and procedures may be needed to capture support for ramp management strategies as well as to define agency expectations for how strategies will be designed, implemented, operated, and maintained. Depending on the importance of issues identified, agreements between agencies can be formal memoranda of understanding, less formal letter agreements, or informal handshake agreements. In any case, it is critical that personnel from different agencies as well as personnel from different departments within the agency responsible for ramp strategy implementation coordinate to thoroughly flesh out the details pertaining to proposed ramp management strategy deployments.
Figure 7-7: Brochure Cover (Reference 2) D
The following sub-sections identify several key policies and procedures necessary to design, implement, operate, maintain, and enforce ramp management strategies. Both intra- and inter-agency policies and procedures are described, as well as the policies and procedures that span the two.
220.127.116.11 Intra-Agency Agreements, Policies and Procedures
Ramp management strategies require approval and support from upper management and other department managers before implementation can be seriously considered. Support is needed from upper management to secure the resources needed for implementation (e.g., personnel, contracts to procure and install communications, field equipment, workstations, and servers as well as any construction needed), operation, and maintenance of strategies. In addition, upper management support is needed to ensure that implemented ramp management strategies will remain an integral aspect of regional transportation directives and that ramp management investments can be expanded to other areas of need, if appropriate. Input from managers of other departments is needed to verify that ramp management strategies fit into current operations and can be seamlessly integrated. Managers of other departments may also identify implementation challenges associated with selected strategies, which can be resolved before strategies are implemented.
18.104.22.168 Inter-Agency Agreements, Policies, and Procedures
Ramp management strategies also require coordination among partner agencies to establish region-wide policies that guide how strategies are implemented and how associated issues are resolved. Coordination needs to continue beyond the planning stages and into the operations stages of ramp management. Several types of agencies with differing agendas will likely be involved with or affected by the operation of ramp management strategies, therefore, policies should be drafted to ensure equity among motorists and agencies across jurisdictional borders. The impacts of ramp management strategies, such as ramp metering, may expand beyond the freeway to local arterials, increasing the traffic demand on the arterial as well as introducing other unwanted impacts (e.g., reduced safety, increased emissions, increased fuel consumption). Without local agency support, continued operation of ramp management strategies may be problematic. It is important to continue the coordination that was established during the planning stages throughout the life cycle of ramp management strategies. Policies and operational procedures should be revisited and modified if needed to make sure that agency needs continue to be met.
Systems, software, and other equipment that support ramp management strategies must be routinely maintained to ensure adequate performance and operational stability. Frequently maintaining systems, software and equipment, helps agencies maximize returns on their investments by offering the best chance for systems to be operated up to and possibly beyond their design life span. This saves the time, effort, and funding needed to purchase new systems before deployed systems reach their designed life span. Failure to maintain ramp management equipment results in disruptions or failure of the strategies or systems that the equipment supports, and makes it difficult to achieve the goals set out for these strategies. Systems that are maintained according to vendor requirements will be useable for longer periods than those that are minimally maintained or not maintained at all.
Maintenance activities associated with ramp management strategies, and most particularly with regard to ramp metering include:
- Replacing defective or broken components.
- Updating software and system inventories.
- Logging repairs.
- Testing equipment.
- Cleaning system components.
When systems or devices fail, staff must be available to fix problems in a timely manner to reduce the impact on and exposure to the public. This is particularly important for systems that support emergency operations, such as automated gates. If ramp management strategies cannot be adequately maintained due to lack of funding or available staff or for other reasons, they should not be implemented. Additionally, if strategies are implemented and they are not routinely maintained, the potential for equipment malfunction will increase. This in turn will result in greater public skepticism of the effectiveness of ramp management strategies, and may in time erode public support for ramp management.
7.3.5 Performance Monitoring, Evaluation and Reporting
Ramp management strategies should be monitored and evaluated to determine if they are achieving their intended objectives, and to make necessary improvements so that optimal system performance can be achieved. Selected strategies should be observed in the field and if possible confirmed in the TMC. If problems are observed or reported, adjustments to the strategies, maintenance, or another responsive action should be performed.
Evaluating the effectiveness of ramp management strategies should not be considered a one-time activity, but should be part of a periodic review of the effectiveness of the component and of the overall system. Ramp management strategies should be analyzed on a continual basis and more formal evaluations should be conducted several times within the first year of deployment and then annually thereafter. Evaluations at two weeks, six months, and one year after initial operation often meet the needs to report how the system is doing in the first year of operation.
The results of performance monitoring and evaluation should be reported to the public, partner agencies and the media. This helps communicate the effectiveness of ramp management projects to these groups, builds a general understanding of the benefits of the ramp management strategy, and builds support for ramp management activities. Reporting formats should be tailored to the specific needs of the audience in which they will be reported.
This section provides two examples where ramp management strategies have been used and have provided benefits.
7.4.1 Ramp Metering (Twin Cities, Minnesota) (3,12 )
The Minnesota Department of Transportation (Mn/DOT) owns and operates an extensive ramp metering system in the Minneapolis/St. Paul metropolitan area (also referred to as the Twin Cities). The ramp metering system has over 430 ramp meters and is one of the most extensive ramp metering applications in the nation. The Twin Cities ramp metering program is used for corridor and regional traffic control and has historically employed some of the most restrictive metering algorithms in the nation. Characteristics of the Twin Cities metering program are captured in Table 7‑3.
Table 7-3: Twin Cities, Minnesota Ramp Metering System Summary
Number of Meters
210 in Twin Cities metropolitan area.
Types of Metering Control Applied
Mix of pre-timed, traffic responsive, and system wide ramp metering.
Time of Day Operations
Both AM and PM peak periods.
Planned Expansion of the System
350 by 2008
Special/Unique Application or Capabilities
Represents one of the most comprehensive ramp metering systems in the United States. Includes some metering of freeway-to-freeway ramps.
The Twin Cities ramp metering system was subject to an extensive and well publicized evaluation in 2000 when the meters were turned off for a six-week period for evaluation of the impacts of the application. An extensive planning and policy review effort followed to modify the region’s metering system to better balance the needs of system operators and regional travelers. Many useful lessons learned resulted from this effort involving the evaluation and performance monitoring of mature metering systems. The lessons learned in this effort illustrate the need for system evaluations, both as a tool for further improving the system and measuring the benefits of the system.
The evaluation of the ramp metering system was mandated by the State legislature. This mandate was prompted by a small, but vocal, group of citizens who were opposed to ramp metering. The legislature directed Mn/DOT to suspend the operation of the metering system for a six-week period and provided funding for a comprehensive independent evaluation of the impacts observed during the shutdown period to identify the overall impacts of the system. Throughout the shutdown experiment, the evaluation was extensively covered in the local media and followed by the public.
System performance data was collected during two six-week periods, both preceding and during the ramp metering shutdown. Data collected prior to the shutdown was used to represent travel conditions “with” the ramp metering system. Data collected during the shutdown period was used to reflect “without” the ramp metering system.
Several performance measures were used to evaluate the ramp metering system. These included traffic volumes and throughput, travel times, reliability of travel time, safety, emissions, fuel consumption, and public perception. The highlights are bulleted below.
- Throughput: Traffic volumes on the freeway mainline were observed to decrease by nine percent when the meters were shut down. There was no appreciable change in the volumes on the parallel arterials observed when the meters were shut down.
- Travel Time: Freeway speeds were reduced by 14 percent, or 11.9 km/h (7.4 mi/h), when the meters were shut down, resulting in greater travel times that more than offset the elimination of ramp queue delays. There was no appreciable change in the travel times on the parallel arterials observed when the meters were shut down.
- Travel Time Reliability: Travel times were nearly twice as unpredictable when the meters were shut down.
- Safety: Crashes on freeways and ramp segments increased by 26 percent when the meters were shut down.
- Benefit/Cost Analysis: The ramp metering system was estimated to produce approximately $40 million in benefits to the Twin Cities region. These benefits outweighed the costs of the ramp metering system by a ratio of 15 to 1.
- Market Research: Survey and focus group efforts were used to gather perceptions and opinions on the metering system. This research revealed that the majority of Twin Cities’ residents supported the use of ramp metering and felt that the system provided them with a benefit. However, many residents also supported modifications to the system to decrease time spent waiting in the ramp queues. The market research findings generally supported the observed impacts of increased safety, improved travel time, and more reliable travel times resulting from ramp meter operation. One noted discrepancy involved the time spent waiting in the ramp queues reported by travelers. Travelers perceived their wait times to generally be twice as great as the observed wait times.
7.4.2 Permanent Ramp Closure (Honolulu, Hawaii)( 13 )
This case study explores the simulated and real-world results of the H-1 freeway entrance ramp closure. The H-1 freeway (eastbound and westbound) qualifies as a severely congested facility because central portions of the H-1 operate below 50 km/h (31.1 mi/h) for at least one hour during the AM peak period.
Project staff started the simulated H-1 freeway ramp closure by analyzing and selecting the appropriate ramp. Using over 30 simulated alternatives, discussions with HDOT Traffic staff, helicopter surveillance, and driver experience, it was determined that the Lunalilo Street entrance ramp was the source of a major bottleneck. The Hawaii Department of Transportation (HDOT) then conducted a two-week ramp closure experiment on the Lunalilo Street entrance ramp in Fall 1997. Ramp metering was considered for the H-1 corridor. However, since both the mainline and entrance ramp traffic volumes were very high, the metering rate would need to have a long cycle, which effectively means closing the ramp since less than 30 percent of the ramp volume would be allowed access. This helped to show that ramp metering would not have been the appropriate solution. In addition, ramp metering would not have been effective given the close proximity of many of the entrance ramps.
Though this ramp closure experiment was just two weeks long, there were some notable lessons learned. First, it is possible to conduct a ramp closure experiment on a major interstate freeway. Not only is it doable and safe, but it is also an affordable option to a ramp metering solution which would require considerable alignment changes in this case. Second, while experimentation is a wonderful method to determine the actual results, a short-term project is not able to attain simulated results because equilibrium and normal driving conditions can not be realized in two weeks time. Third, detailed simulations can be an effective representation of existing traffic conditions and future traffic conditions. Lastly, this experiment demonstrated a successful and cooperative multi-agency effort. Both HDOT and the City and County of Honolulu worked well together to meet the extraordinary demands of this short-term project.
Specifically, the positive impacts of the ramp closure included:
- Though ramp metering would be a less disruptive alternative, it would have required extensive alignment modifications to meet the storage and acceleration requirements. Therefore, using the entrance ramp closure was a much more economical solution.
- The geometry of the Lunalilo Street entrance ramp was particularly favorable for a ramp closure. This entrance ramp extends to become the right lane of the two-lane Vineyard Boulevard exit ramp. This closure re-routes the traffic to a high-design arterial street (Vineyard Boulevard) which reconnects to the freeway further downstream. And the remaining left lane at the Vineyard Boulevard exit ramp was sufficient to allow mainline motorists off the freeway.
The negative impacts of the ramp closure included:
- Since the experiment was only two weeks in length, the results were not comprehensive enough.
- Ten percent of freeway motorists rated the experiment bad or very bad. This mostly applied to the drivers who exited early and did not experience the experiment site and therefore perceived longer travel times.
- Fifty-two percent of the Lunalilo Street entrance ramp users found the experiment to be bad or very bad.
Motorists who exited at or past the experiment site gave consistently higher ratings than those who exited earlier. It is clear that the motorists who exited early and did not experience the experiment site perceived longer travel times.
A majority of the freeway motorists (51 percent) found the experiment to be good or very good. Of the motorists who use the Lunalilo Street entrance ramp, 25 percent found the experiment to be good or very good, and 23 percent found it neutral.
The two-week ramp closure experiment lead to a formal pilot project aimed at easing congestion on the H-1 freeway. The pilot project, which began in August 2004, closed the Lunalilo Street entrance ramp to morning weekday commuters from 6:00 to 9:30 AM. This was an attempt to eliminate a dangerous, traffic-slowing weave on the freeway. The State’s preliminary data showed the change was working and has had little effect on area residents. The results were as follows:
- Travel time savings on the H-1 freeway after the project started was 10 minutes.
- The time it took to get from Piikoi Street to the freeway’s Queen Emma Overpass via the Lunalilo Street entrance ramp was an average of 9.2 minutes before the demonstration. With the rerouting, the same distance was covered in 4.5 minutes.
- There was no difference in the amount of traffic on the Punahou Street H-1 entrance ramp before and during the ramp closure project.
- There was a small increase of traffic on the School Street entrance ramp, but the increase was not enough to create congestion around the ramp.
In October 2004, the State decided to extend the Lunalilo Street entrance ramp closure project so more data could be collected and community concerns answered.
Surveys handed out to motorists since the change show that 70 percent of the drivers near ‘Ainakoa Avenue in Kahala rated the project very good or good. However, 39 percent of the drivers on Vineyard Boulevard, where the Lunalilo Street traffic has been diverted, said the project was bad or very bad.
Closing the Lunalilo Street entrance ramp in the morning rush hour has helped thousands of East Honolulu commuters on H-1 freeway get to work faster, but Makiki residents say they have paid the price for the convenience of others. The State Transportation Director said that the demonstration project closing the entrance ramp has been a success, but that a final look at the Makiki concerns must be done before making the ramp closure change permanent.
In Fall 2004, the Lunalilo Street entrance ramp closure project was made permanent. Since this time HDOT staff have been working with a local engineering firm to implement ways to automate the closure with devices such as a retractable/collapsible curtain of delineators and a zipmobile for relocating New Jersey style barriers (14 ).
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12. Mn/DOT Ramp Meter Evaluation -- Phase II Evaluation Report. Prepared for Minnesota Department of Transportation. Cambridge Systematics, Inc. May 2002.
13. Leidemann, Mike. “State holds off on-ramp action until Makiki poll.” The Honolulu Advertiser, March 17, 2005. Available: http://the.honoluluadvertiser.com/article/2005/Mar/17/ln/ln36p.html
14. Prevedouros, Panos. E-mail. February 13, 2006. firstname.lastname@example.org