Developing a Resilient Life Cycle Strategy for Pavements

Maine DOT

Maine is a cold-weather state with soils that are susceptible to severe frost conditions during winter months. In cooperation with FWHA and its Transportation Engineering Approaches to Climate Resiliency (TEACR) effort, Maine DOT undertook a project to assess the impacts of changing climate on the performance of pavements and develop strategies to offset those changes. The study looked at anticipated changes in both temperature and precipitation over the course of the 21st century. The study followed the ADAP process as shown in figure 4.6. The study indicated that anticipated climatic changes will lead to moderate changes in pavement performance. The study identified both engineering and operational adjustments Maine DOT can adopt to address these changes. The full report can be found on FHWA’s website at: https://www.fhwa.dot.gov/environment/sustainability/resilience/ongoing_and_current_research/teacr/me_freeze_thaw/

Read more in the chapter: 4.1.3 Developing Life Cycle Strategies

Overhead Sign Structures – Condition-Based Management

Indiana DOT

Overhead sign structures are critical to safe and effective highway performance since they support signs, cameras, sensors and other equipment in support of routine and emergency operations. These structures typically have long service lives, but failure risk exists if they are not maintained. Indiana DOT found that failure to their overhead sign structures could be effectively mitigated through routine, real time condition monitoring and condition forecasting for predicting failure. Therefore, the Indiana DOT uses a condition-based approach for maintaining its overhead sign structures.

Indiana DOT’s condition-based maintenance approach involves the steps listed below to ensure the overhead sign is installed corrected, material specifications are met, and the connection to the ground is secure:

• Professional engineers perform inspections
• An asset inspection report is developed
• The asset inspection reports are submitted to the districts
• The districts review the reports and prioritize work activities
• Work orders are developed to address the highest-priority needs
• In-house crews or local contractors perform the work

As a result of the DOT’s condition-based maintenance approach, the department realized an increase in the amount of collaboration between districts and an improvement in how overhead sign structure repairs and replacements are monitored and prioritized.

Source: FHWA (2019). Handbook for Including Ancillary Asses in Transportation Asset Management Programs (pending publication in 2019).

Read more in the chapter: 4.2.1 Life Cycle Management Approaches

Using Computerized Management Systems to Optimize Life Cycle Management

Minnesota DOT

In its 2019 Transportation Asset Management Plan (TAMP), MnDOT went beyond the scope of pavements and bridges as mandated by 23 CFR Part 515, addressing a comprehensive range of assets, including culverts, deep stormwater tunnels, overhead sign structures, high-mast light tower structures, noise walls, traffic signals, lighting, pedestrian infrastructure, buildings, and intelligent transportation system (ITS) components. MnDOT established expert work groups for each asset class to assess data availability, risks, mitigation strategies, measures, targets, and investment strategies. The Transportation Asset Management System (TAMS) was developed to manage asset inventory, condition data, and capture maintenance resources. TAMS integrates asset data, historical expenditures, and decision trees for culvert maintenance, facilitating life-cycle analysis, maintenance demand estimates, and performance evaluation. While traffic signals and ITS assets are being analyzed within TAMS, building management and sidewalk data are stored in separate databases.

Read more in the chapter:

Use of a Pavement Management System to Establish a Life Cycle Strategies

Ohio DOT

As required under MAP-21, Ohio DOT conducted a risk assessment to identify the most significant threats and opportunities to its pavements and bridges. The analysis revealed that anticipated flat revenues, combined with the annual increases in cost to pave roads and replace bridges, would lead to significant reduction in conditions without changes to existing practice. The potential deterioration in pavement and bridge conditions were expected to significantly increase future investment needs due to the increase in substantial repairs that would be required.

Following the risk assessment, a life cycle analysis was conducted. The analysis found that by focusing on the increased use of chip seals and other preventive maintenance treatments on portions of the pavement network, the annual cost of maintaining the network could be reduced. A life cycle analysis for bridges showed similar results. The bridge analysis found that with just 5 percent of the NHS bridges receiving a preservation treatment annually, the DOT could reallocate $50 million each year to other priorities. The investment strategies outlined in the TAMP and the changes made to the DOT’s existing business processes enabled the agency to offset the potential negative impact of the anticipated flattened revenue projections.

The differences in the adopted life cycle strategies are compared to the past strategies in the Figure. Although the total number of treatments applied over the analysis period increases, the annual life cycle cost decreases because of the reduction in the number of rehabilitation strategies needed.

Ohio DOT’s Pavement Preservation Strategy Comparisons

Source: Ohio DOT Transportation Asset Management Plan. 2018. http://www.dot.state.oh.us/AssetManagement/Documents/ODOT_TAMP.pdf

Read more in the chapter: 4.3.1 Managing Assets Using Condition Based Management

Deterministic Modeling of Culvert Condition

Halifax Regional Water Commission

Halifax Regional Water Commission (Halifax Water) has employed a deterministic modelling approach to create a plan for their storm water assets. The management system was used for long-term planning their culvert portfolio (approximately 1744 cross culverts on 3700 lane km of regional roads). The software uses deterioration curves, a temporal model periodic simulation model and has integrated Geographic Information System (GIS) capabilities.

Initially the analytical objective of the model was to maximize the average condition of all the culverts and minimize the investment. Several constraints were embedded within the initial model analysis including:

• Non-Increasing percentage of culverts in critical condition
• Replace all culverts that exceed expected useful life
• Budget not to exceed scenario

The scenario analysis allowed Halifax Water to establish a minimum investment level required to bring the portfolio to an acceptable average condition state, have a reliable forecast of future condition trends, and quantify an estimate of accepted risk of failures. The figure below shows the agency’s forecasted risk of failure over time based on the selected strategy and projected funding.

Read more in the chapter: 4.3.1 Managing Assets Using Condition Based Management

Interval-Based Approach to Managing ITS Assets

Nevada DOT

Nevada DOT recognized that the level of investment in ITS equipment (e.g., closed-circuit cameras, dynamic message signs, flow detectors, highway advisory radios, environmental sensor stations, and ramp meters) was increasing significantly and the importance of this equipment to network operations was growing. As a result, the DOT chose to establish a method of managing its ITS assets that would minimize the risk of failure and provide information to support budgeting activities. However, since the DOT had limited data on its ITS components, a process was developed that relied on the following factors to establish maintenance cycles:

• Historical performance
• The typical timeframe before the software became outdated
• Manufacturer recommended service life
• To determine the condition of ITS traffic cameras, Nevada DOT developed a transition probability matrix with four condition criteria based on the device manufacturers’ recommended service life as follows:
  • Good – device age is less than 80 percent of the manufacturer’s recommended service life
  • Low risk – device age is between 80 to 100 percent of the manufacturer’s recommended service life
  • Medium risk – device age is between 100 to 125 percent of the manufacturer’s recommended service life
  • High risk – device age is greater than 125 percent of the manufacturer’s recommended service life

The transition probability matrix was used to model ITS asset deterioration and program maintenance actions over a 10-year analysis period via the use of a simple spreadsheet tool. The results of this analysis showed an interval-based approach to managing ITS assets would result in an estimated savings of $1.1 million over a 20-year period.

Source: Nevada DOT TAMP (2018)

Read more in the chapter: 4.3.2 Applying Other Life Cycle Management Approaches

Risk-Based Rock-Fall Management Program

Colorado DOT

Colorado DOT responds to between 50 and 70 geotechnical emergencies a year. The traditional approach to managing rockfalls was based on the size and frequency of rockfalls. This approach did not consider the criticality of the facilities that could be impacted by a geohazard event. Since 2013, the Colorado DOT has used a risk-based approach to evaluate and prioritize geohazard mitigation activities based on the size of the geohazard areas and the frequency of falls. Colorado DOT’s approach includes a measure of Risk Exposure (RE), which is based on three components:

• Average Annual Daily Traffic (AADT).
• Likelihood of a Vehicle Being Affected by a Geohazard Event. This metric considers site-distance, the number of previous rock-fall accidents, and a measure of how frequently a vehicle is below the hazard on a daily basis.
• Reduction Factor. This considers the effectiveness of prior mitigation actions, to reduce the RE score.

Colorado DOT’s geohazards program uses the RE to allocate an annual budget of about $10 million to manage geohazards. Due to the inherent uncertainty of geohazard management, in addition to the geohazard management program, maintenance staff regularly patrol highways known to have geohazards. If a hazard requiring immediate action is identified, maintenance crews respond promptly. Using the RE for prioritization allows Colorado DOT to focus its efforts on reducing the impact of geohazards on users of the highway system.

Read more in the chapter: 4.3.2 Applying Other Life Cycle Management Approaches

Linking Maintenance Strategies and TAM Policies

AASHTO

The following hypothetical examples show how policy and management strategy work together to deliver transportation services and manage risks.

Reactive Strategy Example – Agency A has determined its guardrail inventory is generally in good condition and typically replaced as part of pavement rehabilitation projects. On average, replacements occur at least every 30 years, which is more frequent than the expected service life ranging from 40 years for cable to 75 years for concrete barrier. As a result, the agency can accept a life cycle strategy of maintaining a complete inventory and annual inspection of a random two-percent sample.

This life cycle strategy introduces the risk of a rail being damaged by collisions or other events and left in service, presenting a danger to highway users. To manage this risk, the agency implements a policy of repairing all damaged guardrail within 3 weeks of becoming aware of damage. Additionally, internal procedures are put in place to notify area maintenance managers of incidents reported through the state police accident reporting system, and standby maintenance contracts are established for guardrail repair to ensure adequate resources are available in compliance with the new policy.

Condition-Based Maintenance Example – Agency B has determined it can provide significant, long-term performance improvement in average bridge condition and service life if it can increase its investments in bridge maintenance activities like sealing concrete, repairing joints and spot painting steel. To fund this initiative, however, the agency must replace three fewer bridges on average each year. The short-term impact of this new life cycle strategy is an increase in the risk of unsafe conditions occurring on bridges that would have been replaced under the previous strategy. To overcome this risk, the agency increases the frequency of inspections on bridges exceeding the level of acceptable risk according to analysis from its bridge management system, and a series of standby contracts are established to provide rapid response of specific structural repairs to extend the service lives of poor bridges by addressing only critical structural deficiencies or risks.

Read more in the chapter: 4.3.3 Implementing Life Cycle Management

Life Cycle Management Across a Diverse Portfolio

Fredericton Transit (Canada)

The City of Fredericton has, over the last 15 years, implemented several life cycle management strategies that have significantly changed how they deliver municipal services with their infrastructure. Three examples are briefly summarized below:

• Long term life cycle planning: Infrastructure accounting policy changes led to the city establishing long term replacement forecasts for each asset class to estimate the sustainable level of funding required for investment for capital budgeting. This required a complete inventory of their assets, changes in how future replacement costs were estimated, as well as changes to the analysis period used for long term planning. At least one life cycle for all assets had to be captured in the forecast horizon.
• The City implemented a Lean Six Sigma strategy to assess processes and how services were delivered. This methodology helped identify efficiency opportunities, but also identified intervention strategies that previously were not considered in project scoping previously.
• The City evaluated its labor and outsourcing policies as a consequence of the lean approach, and in some circumstances, shifted resources to have dual roles for service delivery, or used external service providers to be responsible for infrastructure, or service delivery.

Read more in the chapter: 4.3.3 Implementing Life Cycle Management

Resource Allocation Policy

Washington State DOT

Washington State DOT has worked closely with its legislature to adopt asset management based resource allocation policies.

The following is an excerpt from state legislation that was last updated in 2002:

”deficiencies on the state highway system shall be based on a policy of priority programming having as it’s basis the rational selection of projects and services according to factual need and an evaluation of life cycle costs...”

– RCW 47.05.010

This legislation along with good business practices has made Washington State DOT have one of the most mature asset management practices and an integrated set of tools, business processes, and organizational culture to support good asset management.

Source: http://apps.leg.wa.gov/RCW/default.aspx?cite=47.05

Read more in the chapter: 5.1.2 Transportation Agency Context

Michigan's Resource Allocation Process

Michigan DOT

Michigan DOT recently introduced principles of performance-based contracting to their routine highway maintenance delivery. The focus of this initiative was on developing a better understanding of performance, providing more consistency of service, encouraging innovation adoption and identifying efficiency opportunities.

To achieve this MDOT developed performance measures for 23 non-winter maintenance activities. They then examined how these activities contributed to the objectives and community outcomes MDOT wanted to achieve (e.g. safety, reliability, economic benefit, and quality of life) and used that analysis to select six initial key measures for which targets were set to focus the effort. The performance monitoring system helped one MDOT region identify unsealed shoulders (ensuring they are even and traversable) as an area requiring improvement. They invested in additional shoulder maintenance in 2015 and from this realized a performance increase of more than 30%.

MDOT is using this performance monitoring approach to better understand the cost of improving its maintenance level of service. The agency is also identifying specific resources to focus in areas where it can achieve a more consistent and safer outcome.

Read more in the chapter: 5.1.3 Prototypical Resource Allocation Process

New Zealand's Resource Allocation Process

Southland District Council (New Zealand)

Southland District Council (SDC) manages one of the largest road networks in New Zealand. Dairy farming is critical to the economy of the local area and more broadly to the Country (SDC generates 10% of New Zealand’s dairy exports). In the period 2000-2010 there had been significant expansion of the dairy farming industry and further expansion was likely. Maintenance and renewal costs were estimated to increase significantly and SDC’s road rates were already among the highest in the country. SDC recognized that a new approach was necessary and they could not keep doing things the same way.

SDC developed the Economic Network Plan as an asset management approach that allowed SDC to determine where investment in the network would provide the greatest financial return to the community. The Economic Network Plan considered the following services provided by the network:

• Safety
• Road Condition (Levels of Service)
• Enable Exports
• Service Delivery
• Customer Quality

Consideration of the resources required to maintain the network led SDC to the decision that its highest volume roads would be maintained to its then-current LOS standard. These roads represented 20% of the road network but carried nearly 70% of the traffic. The remaining 80% of the network would have a reduction in standard over time. The Economic Network Plan provided the basis for this change.

Like many agencies, the SDC was forced to take a different approach when financial constraints required change. It enabled all parties to focus on:

• Shifting from ‘Engineering’ to ‘Customer Service Network Management’ (why the service is provided)
• Managing customer expectations proactively rather than reacting to them
• Making safety a priority
• Investing in technology and information to understand, manage and integrate with HCV operators

Source: https://www.nzta.govt.nz/assets/Road-Efficiency-Group-2/docs/southlandnetworkplan.pdf

Read more in the chapter: 5.1.3 Prototypical Resource Allocation Process