Performance Measures in Snow and Ice Control Operations (2019) / Chapter Skim
Currently Skimming:
Pages 7-82
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 7... ...
P A R T I Research Overview
|
From page 9... ...
9 1.1 Background Monitoring the performance of snow and ice control operations has increasingly become an important task for highway agencies and contractors because of increased and changing stakeholder expectations. Different indicators have been used to assess performance in the United States and abroad, with varying degrees of success.
|
From page 10... ...
10 Performance Measures in Snow and Ice Control Operations Fay et al.
|
From page 11... ...
Introduction 11 in snow and ice control" (Welch and McConkie 1976)
|
From page 12... ...
12 Performance Measures in Snow and Ice Control Operations as a top priority (Scott 2007) , and "establishing consistent national LOS and performance measures for winter maintenance" was identified as a priority for research by Nixon (2010)
|
From page 13... ...
13 The study methodology included the following steps: • Step 1: Conduct literature review, • Step 2: Evaluate performance measures, • Step 3: Identify core performance measures, • Step 4: Develop guide, and • Step 5: Develop support tools and materials. 2.1 Literature Review The research team conducted a literature review and documented current practices reported in the United States and internationally for snow and ice control performance measures, focusing on the following questions: • What are the new performance measures beyond those identified in NCHRP Project 6-17, especially for the core categories of bare pavement, traffic speeds, and crash risk?
|
From page 14... ...
14 Performance Measures in Snow and Ice Control Operations • Increased sophistication and improvements in winter maintenance responses at agencies. These include better training of staff in effective winter maintenance and proactive approaches to management, which are improving agencies' abilities to manage adverse weather and achieve better outcomes.
|
From page 15... ...
Research Approach 15 • Reflect current issues; • Allow for comparison of products, equipment, and so forth; • Allow for prediction of future trends in planning and budgets; and • Allow for comparison of performance across states (Adams et al.
|
From page 16... ...
16 Performance Measures in Snow and Ice Control Operations Criteria Rating Guide High Medium Low Measurable Measurement is straightforward and objective. Measurement is relatively straightforward but subject to some interpretation or assumptions.
|
From page 17... ...
Research Approach 17 • Resource usage measures that document material, fuel, and labor use are formed frequently in agency performance reports. In best cases, they are reported along with an indication of the severity of the season (which may be a calculated index or a measure of weather incidence such as weather hours)
|
From page 18... ...
18 Performance Measures in Snow and Ice Control Operations the event. Mobility and customer satisfaction measures are primarily collected during the same time frame.
|
From page 19... ...
Research Approach 19 While the guide mainly focuses on roadways, it is a flexible and inclusive document. Many of the concepts described in the guide are capable of being adapted to measure the performance of winter maintenance operations that focus on other infrastructure (such as bike paths and sidewalks)
|
From page 20... ...
20 Performance Measures in Snow and Ice Control Operations systematic process that allows agencies to define, implement, use, and evaluate performance measures that satisfy their needs. The content and structure of the guide were created with the following principles in mind: 1.
|
From page 21... ...
21 3.1 Current Practices for Snow and Ice Control Performance Measurement Adams et al. described principles to guide the selection of performance measures.
|
From page 22... ...
22 Performance Measures in Snow and Ice Control Operations Other research activities in snow and ice performance are discussed in the following: • In a pilot study in Michigan, Bandara (2015) developed a relationship between visually observed pavement conditions and measured friction.
|
From page 23... ...
Findings and Applications 23 – Laser guides, and – Tailgate versus hopper spreaders.
|
From page 24... ...
24 Performance Measures in Snow and Ice Control Operations Snow and ice performance measures can also help inform a number of planning, management, and operations decisions related to winter maintenance, including those related to: • Material management. Understanding how operations activities (e.g., plowing and applying chemicals)
|
From page 25... ...
Findings and Applications 25 3.3 International Practices Significant knowledge can be gained by examining how transportation agencies in other snow-affected countries measure performance with respect to snow and ice control. A key component of NCHRP Project 6-17 and several other research efforts was to determine how transportation agencies in other countries have managed the challenge of removing snow and ice to minimize negative effects on the transportation system, businesses, and the traveling public.
|
From page 26... ...
26 Performance Measures in Snow and Ice Control Operations Country Framework Measures Used Technologies Used Other Notable Points Canada Quebec – 2006 Sustainable Development Act has management framework. 59 service centers in Quebec – contract with companies and municipalities to provide services.
|
From page 27... ...
Findings and Applications 27 Country Framework Measures Used Technologies Used Other Notable Points South Korea Road authorities must meet required standards for maintenance – road levels are responsibilities of different authorities (national down to county level)
|
From page 28... ...
28 Performance Measures in Snow and Ice Control Operations 3.4 Challenges and Constraints to Performance Measurement The challenges to effective performance measurement in snow and ice control operations involve defining successful practices and the effectiveness of the actions performed. Mewes et al.
|
From page 29... ...
Findings and Applications 29 response. For example, a light winter in a heavily urban area might necessitate a higher level of response over a season than that of a rural region with a high WSI.
|
From page 30... ...
30 Performance Measures in Snow and Ice Control Operations systems is the RCRS. The RCRS is often a focal point; it is populated by manual and automated data and information feeds, and it supplies information to various information dissemination mechanisms.
|
From page 31... ...
Findings and Applications 31 material in the right place at the right time. Technologies discussed in the report included AVL, surface temperature measuring devices, freezing point and ice-presence detection sensors, salinity measuring devices, visual and multi-spectral sensors, and millimeter wavelength radar sensors.
|
From page 32... ...
32 Performance Measures in Snow and Ice Control Operations change, the greater emphasis on life-cycle costs and clear identification of assets will have an impact on snow and ice performance measurement. 3.5.5 Increased Importance of Transportation Resilience Transportation resilience is a critical part of providing a safe, reliable transportation system.
|
From page 33... ...
Findings and Applications 33 measurement programs are expected to be identical. Nevertheless, some best practices have been developed for establishing performance measurement programs (Grant et al.
|
From page 34... ...
34 Performance Measures in Snow and Ice Control Operations precipitation might have stopped (for example, blowing snow) , or continuing response activities.
|
From page 35... ...
Findings and Applications 35 often submitted by radio or onboard device. In addition, several agencies have implemented citizen reporting programs, thereby increasing the number of quality reports received.
|
From page 36... ...
36 Performance Measures in Snow and Ice Control Operations operations use severity to classify individual winter events and the entire winter season based on event and overall characteristics, such as (total) precipitation and wind speed.
|
From page 37... ...
Findings and Applications 37 describing the appropriate storm event elements to be analyzed and used for the development of the SSI. Table 4 provides a summary of elements found in the literature.
|
From page 38... ...
38 Performance Measures in Snow and Ice Control Operations 2. Decide the storm elements' measure units and categories.
|
From page 39... ...
Findings and Applications 39 and total storm duration. Indiana DOT's WSI is similar, using these same factors, plus number of incidents, snow depth, storm intensity, and average temperature.
|
From page 40... ...
40 Performance Measures in Snow and Ice Control Operations b. Consensus through survey assigns initial or final weights to each element.
|
From page 41... ...
Findings and Applications 41 Ongoing Data Collection Throughout the Winter Season Injury Crash Records Definition: Documentation of crashes where at least one individual was injured as a result of adverse weather conditions; typically scaled for severity of injuries; finalized 30 days after the crash to remove fatalities occurring during that period. Data source: Crash records maintained by state transportation agency safety management group or law enforcement agencies; TMC incident records.
|
From page 42... ...
42 Performance Measures in Snow and Ice Control Operations Data Collected Once or at Beginning of Winter Season Customer Satisfaction Levels Definition: Assessment of traveler satisfaction with snow and ice response. Data source: Periodic surveys of travelers either conducted seasonally or after selected events.
|
From page 43... ...
43 The following sections describe how agency missions and goals drive performance measurement through the identification of operational objectives. Seven operational objectives were identified and, correspondingly, seven performance measures are described in detail.
|
From page 44... ...
44 Performance Measures in Snow and Ice Control Operations Question Options Impact on Performance Expectations and Measurement How important is snow and ice control to the agency's mission? Agencies are likely to have a dedicated winter maintenance program.
|
From page 45... ...
Development of Performance Measures 45 For snow and ice control, outcome-related operational objectives are ideally defined within the seven categories identified in Figure 6. Each of the seven objectives sets a performance standard that can be measured and reported.
|
From page 46... ...
46 Performance Measures in Snow and Ice Control Operations Ways to Define LOS During an Event Approach Comments Maximum accumulation during the course of the event (Measured)
|
From page 47... ...
Development of Performance Measures 47 are not likely to have the same recovery targets. Objectively defining what constitutes "recovery" or is a return to normal is the primary challenge in measuring this objective.
|
From page 48... ...
48 Performance Measures in Snow and Ice Control Operations over the event horizon should be computed from the NPMRDS aggregated to the same analysis period (5 to 15 min) as the base travel time data.
|
From page 49... ...
Development of Performance Measures 49 4.2.4 Safety-Related Objectives Important objectives of winter maintenance activities are to improve safety and reduce the risk of fatal crashes for all transportation system users in the midst of adverse winter weather. Crash data can provide valuable insight into the success of snow and ice control operations.
|
From page 50... ...
50 Performance Measures in Snow and Ice Control Operations of around $11.7 million per 8-h closure for the freight industry. Road closures, however, can help agencies avoid elevated incident costs and the costs associated with rescuing injured and stranded motorists.
|
From page 51... ...
Development of Performance Measures 51 4.3 Linking Performance Measures to Operational Objectives Seven performance measures were identified to support monitoring the seven objectives. Each performance measure includes many variations that are related to agencies' capabilities.
|
From page 52... ...
52 Performance Measures in Snow and Ice Control Operations Objective measures of service quality during an event, such as measured accumulation amounts or measured grip factors, are preferred. Service-level thresholds can be stated in one of the following forms: • Road condition–related.
|
From page 53... ...
Development of Performance Measures 53 The selected service-level threshold is defined by the agency and will depend on one or more of the following functions: • Roadway functional class. Higher levels of service may be expected for higher-priority roadways (e.g., Interstates)
|
From page 54... ...
54 Performance Measures in Snow and Ice Control Operations could also encourage higher speeds when they are not warranted, particularly where variable speed limit systems are in place. – Access-related threshold.
|
From page 55... ...
Development of Performance Measures 55 Translating time-stamped surface conditions to the winter weather event status allows an agency to determine how quickly the segment recovered from the event. 4.3.2.1 Measure Definition This performance measure assesses the amount of time that passes from the end of a winter event until an acceptable surface condition once again exists (e.g., bare pavement)
|
From page 56... ...
56 Performance Measures in Snow and Ice Control Operations • A variation of this measure substitutes a time to return to normal speed or free-flow speed in lieu of bare pavement. While the variation may benefit from less subjectivity and, potentially, more abundant and precise time stamps offered by speed data, this measure's variation could encourage unsafe driving speeds instead of improved performance of snow maintenance activities.
|
From page 57... ...
Development of Performance Measures 57 Implied in the Definition • Event duration. Agencies should select a period that consistently encompasses most winter weather events.
|
From page 58... ...
58 Performance Measures in Snow and Ice Control Operations • Weather information. Data from RWIS regarding rate or total precipitation or grip will be needed to determine storm severity, an accumulation-related threshold, or a friction-related threshold.
|
From page 59... ...
Development of Performance Measures 59 4.3.4.2 Weaknesses and Limitations of the Measure • Availability of crash data is often delayed due to processing. In part, this is because some crashes cannot be immediately categorized since generally any injury that results in a death within 30 days is listed as a fatality.
|
From page 60... ...
60 Performance Measures in Snow and Ice Control Operations • If reliably documented causal factors are available in detailed crash records, these may be examined to identify specific areas to improve winter maintenance operations. However, inconsistencies and subjectivity with reporting causal factors make this less conducive for calculating a performance measure.
|
From page 61... ...
Development of Performance Measures 61 performance. Collecting information about demographics enables agencies to consider whether satisfaction varies based on socioeconomic status.
|
From page 62... ...
62 Performance Measures in Snow and Ice Control Operations 4.3.6 Cost of Snow and Ice Control to Meet Established Performance Criteria for a Given Winter Severity Agencies attempt to correctly translate their usage of different resources into the cost of winter maintenance operations and use this information to assess the efficiency of their spending. "Cost" here refers to a standardized cost, which can be the cost per number of lane miles under the agency's jurisdiction, for instance.
|
From page 63... ...
Development of Performance Measures 63 – Miles covered, – More detailed geographical areas, such as census tracks, – Cost per type of activity (e.g., anti-icing and deicing) , and – Traffic level [winter average daily traffic (WADT)
|
From page 64... ...
64 Performance Measures in Snow and Ice Control Operations Included in the Definition • Season duration. Agencies should select a period that consistently encompasses most winter weather events.
|
From page 65... ...
Development of Performance Measures 65 4.4 Target Setting 4.4.1 Background on Target Setting This section summarizes available guidance on target setting for performance measurement. Performance target setting is an important and complex process through which agencies analyze expected performance and account for factors that will affect performance in the future, including levels of available funding and the relative emphasis placed on achieving different targets for the transportation system.
|
From page 66... ...
66 Performance Measures in Snow and Ice Control Operations Step 1 – Define Purpose Agencies should be able to link their targets directly to their goals and need to clearly state their goals so that they can be converted into measurable objectives. Therefore, agencies need to: • Assess why they are setting the snow and ice control operation targets; • Link performance to the agency's overall and winter maintenance objectives, resources, and requirements; and • Use the agency's overall and winter maintenance purposes to inform target parameters and guide target establishment.
|
From page 67... ...
Development of Performance Measures 67 • Budget and resource constraints, • Senior management directives, • Agency jurisdiction, • Agency goals and priorities, and • Planned operational activities. Other considerations that agencies need to take into account are: • Fiscal limitations and trade-offs, • Constraints and existing commitments, both within agency and to stakeholders, • How factors will change over the time span of a target, • Risk associated with each of the factors, including magnitude and likelihood of risk, and • Documented assumptions involved with building each factor into the target-setting process.
|
From page 68... ...
68 Performance Measures in Snow and Ice Control Operations 4.4.2 Evaluating Winter Maintenance Through Performance Curves Winter maintenance performance curves are graphical representations of how an agency operates under various winter conditions. They illustrate the correlation between selected performance measures and indicators of severity.
|
From page 69... ...
Development of Performance Measures 69 The return to bare pavement measure is based on the following definition: "all driving lanes are 95% free of snow and ice between the outer edges of the wheel paths and have less than one inch of accumulation on the center of the roadway" (Minnesota DOT 2017) Plow operators report on bare pavement based on their visual observations, which are used to calculate a measure of time to return to bare pavement following a winter weather event.
|
From page 70... ...
70 Performance Measures in Snow and Ice Control Operations The targets for return to bare pavement vary by road classification: • Super commuter: 0–3 hours. • Urban commuter: 2–5 hours.
|
From page 71... ...
Development of Performance Measures 71 this guide for mobility and sustainability measures. Specifically, MnDOT reports the frequency of meeting regain time targets for agency-defined segments over the winter season.
|
From page 72... ...
72 Performance Measures in Snow and Ice Control Operations water supply wells with hard or very hard water. A Winter Maintenance Assessment tool has also been developed by the Minnesota Pollution Control Agency for use by winter maintenance professionals across the state to understand current practices, identify areas of improvement, and track progress.
|
From page 73... ...
Development of Performance Measures 73 In 2007, ITD deployed a network of RWIS sites statewide to monitor atmospheric and pavement conditions. These RWIS sites included nonintrusive pavement sensors that remotely measure temperature and surface conditions (e.g., dry, wet, snow, and ice)
|
From page 74... ...
74 Performance Measures in Snow and Ice Control Operations 4.5.2.1 Winter Mobility Index ITD developed a second performance measure, the winter mobility index, to assess how well road treatments perform when temperatures are below freezing. This performance measure can guide both the timing of treatment application and the selection of road treatment material.
|
From page 75... ...
75 5.1 Conclusions Snow and ice performance measurement does not occur in a vacuum, and it is influenced by trends and crosscutting issues that occur elsewhere in the transportation field. These trends can provide new ways to define and measure performance for snow and ice control.
|
From page 76... ...
76 Performance Measures in Snow and Ice Control Operations snow and ice control activity performed to the measure may be indistinct, but overall trends may still be valuable for the agency to support investments in snow and ice management. • Starting the process of performance measurement is the first and perhaps the most important step.
|
From page 77... ...
Conclusions 77 5.2.1 Define and Use a Weather Event as the Starting Point for Performance Measurement Transitioning from a seasonal approach to management to an event-based, data collection approach allows for greater flexibility in the definition of performance measures. There are many ways of defining an event, but consistency across an agency's jurisdiction is more important than the selection of a specific approach.
|
From page 78... ...
78 Adams, T., Danijarsa, M., Martinelli, T., Stanuch, G., and Vonderohe, A
|
From page 79... ...
References 79 Conger, S
|
From page 80... ...
80 Performance Measures in Snow and Ice Control Operations Iowa DOT.
|
From page 81... ...
References 81 Mirtorabi, R
|
From page 82... ...
82 Performance Measures in Snow and Ice Control Operations http://www.ukroadsliaisongroup.org/en/utilities/document-summary.cfm? docid=C7214A5B-66E1-4994AA7FBAC360DC5CC7.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.