Applying Transportation Asset Management to Intelligent Transportation Systems Assets: A Primer
Chapter 5. Performance Measures and Targets
Identifying objectives is a key element of effective asset management. TAM objectives should align with the vision and mission of the agency. To achieve these objectives, performance measures should then be identified and tracked.
FHWA TAMP Elements: Asset Management Objectives, Measures and Targets, Risk Management
(23 CFR 515.9(d)(1)-(2), (d)(6))
This theme is extrapolated from three TAMP elements: asset management objectives, performance measures and targets, and risk management analysis. Once an agency has developed its asset management objectives, it can move forward in setting performance measures and targets to achieve those objectives. This emerging theme addresses common performance measures for traffic signals asset management that should then ultimately be linked to the agency’s objectives around these assets. Performance measures can provide excellent insights on assets condition and operational status, helping the agency make better data-driven decisions and better assess, manage and mitigate related risks.
Establishing performance targets allows agencies to track progress towards their goals and guide the allocation of resources to projects and programs with significant impacts on performance. Performance targets should be based on projected available transportation funds and aligned with applicable Federal requirements and State goals and objectives. For ITS assets, and most asset classes in general, agencies have found it critically important to track multiple performance measures, aside from age and/or just condition.
Many international transportation agencies and an increasing number of U.S. agencies have noted the importance of tracking asset availability, or the “calculated percentage of time the asset is in a nonfailed state over a period of time. The asset is categorized to be in a failed state if it is in a degraded state or unavailable, or both” (Luk et al. 2013). This definition was created by Austroads, an association of transportation agencies in Australia and New Zealand that creates guidelines, codes of practice, and research reports to promote best practice for road management. Austroads describes asset availability as the result of the combined effect of asset reliability/condition and asset maintainability/serviceability, more specifically:
- Asset Reliability/Condition—Continuous performance of an asset to its design/intended function without failure under normal conditions during a period of time. It can be calculated as failure frequency or mean time between failure as well as defined by the age and visual condition.
- Asset Maintainability/Serviceability—The time it takes to restore the asset when it fails. It can be calculated as the mean down time (i.e., covering fault identification, response and repair time) or assessed by the type and frequency of maintenance performed on the asset (e.g., preventive versus reactive maintenance, maintenance response time).
Austroads explains that asset availability can be enhanced by either improving reliability (i.e., reducing faults) and/or improving maintainability (i.e., quickly identifying and rectifying faults). These two performance measures are further explained and illustrated below.
With the expansion of centralized systems with communication to each ITS device, it is more feasible to monitor the devices for downtime due to power outages, light failures, and other electronically trackable issues than it was years ago, when the few ITS devices were operated in isolation with no communications or tracking ability. Agencies can now quickly assess the risk of device failure/downtime and target fixes (i.e., if an ITS device has an inordinate number of power outages, it may be justifiable to install a battery backup system to keep the asset operational).
Also, as more agencies quantify their actions (asset deployment or maintenance for example) through a benefit/cost approach, risk for ITS asset failures can be measured more effectively to prioritize proactive maintenance/risk mitigation.
Asset Reliability/Condition
Asset condition is the foundational measure for the health and physical integrity of an asset and the reliability of the asset. In many cases, agencies measure condition based on age or remaining useful life. This is a valid approach, especially when just getting started in asset management for the respective asset class, in this case ITS assets. Agencies are starting to adopt more robust approaches for ITS asset condition, however, including visual condition scores based on visual inspection, age, and component assessments, rather than purely age or overall asset assessments.
Setting Performance Measures—Utah DOT
As part of a strategic goal of preserving infrastructure, Utah DOT sets performance measures and targets for signal systems, such as the percent of signals that are in good or fair condition, based on an annual inspection of all electronics and the physical infrastructure associated with signal systems. Utah DOT collects and posts its data and performance measures publicly, which contributes to its long-term planning success. Further, the agency has benefited from experienced senior leaders overseeing and championing the planning process. The agency lists key measures and targets for traffic signals in its dashboard and provides a visual representation to help convey outcomes to the public. Table 4 illustrates some of Utah DOT’s traffic signal performance measures.
Table 4. Intelligent transportation system and traffic signals performance measures for Utah Department of Transportation.
| Measure |
Target |
| Number of traffic signals |
– |
| Maintenance funding/traffic signal |
$3,400/year |
| Connected signals that are communicating |
97.5% |
| Average time to close signal maintenance work order |
5 days or less |
| Signals with preventative maintenance performed |
100% |
| Traffic signals/signal technician |
50 maximum |
| Traffic signals/signal engineer |
100 maximum |
| Construction projects reporting lane closures |
90% key routes reporting |
| Lane closures activated changed or canceled |
85% by June 2018 |
| Planned events managed |
90% Level 1 events by June 2018 |
| Road weather information system devices operational |
95% |
Condition Ratings—Nevada DOT
Nevada DOT maintains and manages several types of ITS assets to address its highway safety and mobility needs. As part of its 2019 TAMP, the following ITS assets were included: CCTV camera devices, DMS, flow detectors, highway activity radios, ramp meters, and RWIS. For 2019 TAMP submittal, since Nevada DOT did not yet have a formally established performance metric for ITS condition, the agency used a simplified subjective performance metric based on the manufacturers’ recommended service for each device was established. As such, Nevada DOT followed the condition categories laid out in table 5, taken directly from its 2019 TAMP.
Table 5. Intelligent transportation systems condition categories for Nevada Department of Transportation.
| Measure |
Target |
| Good |
Age of the device is less than 80 percent of the manufacturer’s recommended service life. |
| Low Risk |
Age of the device is between 80 and 100 percent of the manufacturer’s recommended service life. |
| Medium Risk |
Age of the device is between 100 and 125 percent of the manufacturer’s recommended service life. |
| High Risk |
Age of the device is greater than 125 percent of the manufacturer’s recommended service life. |
The investment strategy for ITS assets focused on maintaining the current levels of service over the next 10 years. Nevada DOT calculated that this would require an average annual investment of approximately $3.6 million without accounting for new ITS assets that are added to the system, as shown in figure 4 from the Nevada DOT TAMP.
Figure 4. Pie charts. Current intelligent transportation systems asset conditions for Nevada Department of Transportation.
(Source: Nevada Department of Transportation 2019.)
For Nevada DOT, the ITS asset maintenance and management strategies discussed in its TAMP cover only the devices and not the supporting structures and other secondary devices that make up the ITS equipment.
Asset Maintainability/Serviceability
Asset maintainability (or sometimes referred to as asset serviceability) is the measurement of the type and frequency of maintenance performed on the asset. Although this may not translate directly to the asset’s reliability or condition, it can provide a good indication of the potential for assets to deteriorate more quickly than planned.
Common maintenance performance metrics may include but are not limited to percent of preventive maintenance versus reactive maintenance, time between initial service request and resolution, and maintenance funding per ITS device.
Asset Performance Measures—Seattle DOT
Seattle DOT started implementing asset management in 2007 and adopted a process of continuous improvement and expanded its asset management planning over time. ITS was added as a new asset class to its 2015 Status and Condition Report. Seattle DOT includes beacons, Bluetooth/Wi-Fi readers, camera assemblies, the communication network, counters, dynamic message signs, network hubs, radar speed signs, the transportation operations center (TOC), and traffic signal assemblies under its ITS category.
Seattle DOT provides descriptions of good, fair, and poor rating standards for all devices, including physical condition and operational condition categories. Performance measures for ITS are included as part of Seattle DOT’s Bridging the Gap (BTG) program. BTG was conceived as a nine-year levy program (mainly from a parking tax) in response to 35 years of deferred maintenance due to shrinking transportation revenues. Seattle DOT gained BTG revenue of more than $40 million per year from 2007 through 2015 (the year the report was published). This revenue also allowed it to further leverage grant funding for infrastructure replacements.
Table 6 shows some of the ITS performance measures used for the BTG program. Additional measures are included in the 2015 Status and Conditions report for each device type.
Table 6. Seattle Department of Transportation asset measures and results.
| Policy Goal/Performance Measure |
2014 Planned |
2014 Results |
2015 Planned |
Goal Met |
| % of Transportation Operations Center downtime due to planned maintenance |
0.01% |
N/A |
0.01% |
Yes |
| Traffic Signal Assemblies—% of downtime due to planned maintenance |
0.01% |
N/A |
0.01% |
No |
| Traffic signal assembly maintenance events |
779 |
779 |
770 |
Yes |
Seattle DOT’s program is an example of good asset management planning for ITS assets and traffic signals for two key reasons: (1) it includes a mature, regularly monitored, and reported set of performance measures for ITS assets and signals; and (2) it relies on performance measures to demonstrate progress to a public audience and make the case for funding, or at least make a clear link between investment in various assets and the performance outcomes.
Asset Maintainability Metrics—Highways England
In 2017, Highways England, a Government-owned company responsible for operating, maintaining, and improving England’s highways and major roads, developed a guide to introduce performance requirements for its technology-related assets. To address asset failures, the agency introduced performance categories to group failures. Highways England requires that all major asset failures that interrupt operations are raised in its Fault Management System within the first hour of notification. For maintenance of traffic technology assets, Highways England defined three levels: first line (onsite repair), second line (at a technology depot or local office), and third line (at a repair facility or returned to the manufacturer, essentially needing to be shipped to a different location).
Highways England uses performance metrics (table 7) to track the maintenance cycles of assets and prevent recurrent maintenance needs due to temporary fixes. It also tracks downtime for technology devices (including both ITS and traffics signals) across three performance categories (urgent resolution faults, service affecting faults, and other faults). The agency only permits “clock stopping” when a third party or situation prevents prompt maintenance.
Table 7. Highways England maintainability metrics (selected items).
| No. |
Metric Description |
Performance Category 1 |
Performance Category 2 |
Performance Category 3 |
| 1 |
Percentage of faults restored within 56 days. |
100% |
100% |
100% |
| 2 |
Percentage of faults restored within 168 hours. |
100% |
100% |
– |
| 3 |
Percentage of faults restored within 48 hours. |
100% |
100% |
– |
| 4 |
Percentage of faults restored within 24 hours. |
100% |
80% |
– |
| 5 |
Percentage of faults restored within 12 hours. |
100% |
60% |
– |
| 8 |
Number of Assessment Periods where no more than 4 faults can occur against any individual asset. |
1 Assessment Period |
1 Assessment Period |
2 Assessment Periods |
| 10 |
Average availability for all assets in the Performance Category within an Assessment Period. |
99.99% |
99.9% |
97.5% |
Reporting Framework for Performance Measures
Conveying performance results is just as important as collecting actual data. Utah DOT populates a shareable and transparent dashboard based on both ITS assets and traffic signal performance metrics and targets. The dashboards are published to Utah DOT’s website (Utah DOT 2019). Table 4 highlighted earlier in this chapter provided some data from Utah DOT’s dashboard.
Agencies should also look at using their management systems to create internal dashboards for varying levels of the organizations, from technicians to supervisors and managers (e.g., displaying maintainability metrics for supervisors, such as average time taken to address work orders, percent reactive versus preventive). Further, several agencies noted that using these measures can help make the business case for investment to leadership and stakeholders, as well as improve internal processes and decisionmaking.
Key Actions
Key actions agencies can adopt or improve upon when implementing performance measures and target settings for ITS assets are listed below.
Develop and Set Asset Management Performance Measures/Targets
Identifying the right set of performance metrics for ITS assets is a critical, early-stage step. It helps drive the data collecting and ensures the agency is meeting its strategic and asset management objectives.
Key Steps:
- Review potential performance categories identified in this section (asset availability, asset reliability, and asset maintainability) and examples from other agencies.
- Determine which performance categories and specific metrics are most applicable to the agency, based on current needs, future demand, similar metrics captured for other asset classes, and current strategic and asset management objectives. Implementing performance measures should be a phased approach starting with basic measures such as age and then visual condition. This phased approach is one way to ease into ITS asset performance management.
- Define the performance measures and set achievable targets based on operational and maintenance plans and available funding.
Develop Reporting Framework and Processes
The agency should develop a dashboard template and produce a high-level quarterly or annual asset management report with executive-level metrics and reporting on key benefits, outcomes, and impacts along with a summary of key initiatives and status.
Key Steps:
- Identify what data needs to be collected to adequately track the performance measures and targets selected (as discussed in chapter 3, Asset Identification, in this primer). This may include but is not limited to the age of the asset, a visual condition score (such as 1 to 5) captured regularly, or the amount of time it takes to address a failed asset.
- Start tracking data over time using the management system or tool. Once initial/sufficient data have been captured, identify which metrics are meaningful to various individuals (executive leadership, senior management, and supervisors) and how those data are best communicated to those types of individuals (e.g., a supervisor might like to see a dashboard in their management system with maintainability metrics, where a visual dashboard illustrating asset availability across the network may be more appropriate for executive leadership).
- Seek feedback from those reviewing reports (or dashboards) to determine if this is the right information and level of details for those individuals; adjust accordingly.
