U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
Measuring the impact of specific roadway safety countermeasures has historically been a challenge. This challenge is exponentially increased when attempting to measure the impact of a suite of countermeasures in a region or corridor. Expansion of predictive modeling and analysis actively support the evaluation and updating of Strategic Highway Safety Plans (SHSP) that establish statewide goals, objectives, and key emphasis areas and integrates the four Es - engineering, education, enforcement, and emergency medical services. This section focuses on those tools and processes commonly used by states and MPOs to improve safety outcomes.
A number of nationally available safety analysis tools were identified that can be utilized to support roadway safety performance planning. A full listing of tools reviewed is presented in Appendix B: Tools Supporting Safety Impact Prediction and described in more detail in the Final Synthesis of Available Predictive Tools and Processes, prepared as an earlier deliverable for this project. In the context of this report, tools include technical assistance materials on websites, computer-based spreadsheets and models, or geo-locating systems. The majority of these tools have been directly supported by FHWA, whether through research, funding, development, training, dissemination, or promotion. Although these tools serve different purposes, each provides transportation planners and engineers with data and information that can be used to enhance safety considerations during the transportation planning process. Table 1 presents a listing of the tools used most frequently by states and MPOs. The table provides a synopsis of each tool's primary purpose and a brief overview of where/how these tools are being applied. Although these are the most popular tools, they still have challenges associated with them and those challenges may also indicate why other tools are not as commonly used.
Table 1: Summary of Commonly Used Tools
|Tool||Primary Purpose||Application Overview|
|Crash Modification Factors (CMF) Clearinghouse||This web-based repository provides information on all documented CMFs and Crash Reduction Factors (CRFs) in a central location to help transportation professionals properly estimate the crash reduction of selected countermeasures when applied to projects.||The CMF Clearinghouse is easy to use and provides guidance as to what CMFs have been successful in other places. Additionally, it highlights those factors that have considerable supporting research regarding their successful implementation.|
|FHWA Geographic Information System (GIS) Tools||This GIS software links safety event data such as crashes and geographic data such as roads and roadway features to allow for advanced spatial analysis and mapping.||The FHWA GIS Safety Analysis Tools are a suite of tools developed on the ESRI ArcGIS platform to allow for advanced safety analyses along specific roadways or road networks. This is done by linking various data elements that may impact safety performance through a common geographic reference system.|
The HSM provides a framework for safety that aids practitioners in performing data analysis, selecting countermeasures, prioritizing projects, comparing alternatives, and quantifying and predicting the safety performance of roadway elements during the planning, design, construction, and operation phases of project development.
The HSM provides a method to integrate quantitative estimates of crash frequency and severity into planning, project alternatives analysis, and program development and evaluation. This ability to connect quantifiable data with safety outcomes allows safety to become a meaningful project performance measure. The HSM assists states and MPOs in creating and achieving goals, objectives, measures, and activities, as well as determining the proper tools for data collection and analysis. It allows for full adoption or adoption of one or more parts based on the capabilities and needs of state or MPO.
|SafetyAnalyst is a set of computerized analytical tools to identify safety improvement needs and supports use of cost-effectiveness analysis to develop a system-wide program of site-specific improvement projects.||SafetyAnalyst offers among the most advanced analysis capabilities and can be used to improve programming of site-specific roadway safety improvements. The tools integrate with the HSM and other performance analysis processes. It follows the full cycle of the roadway safety management process, starting at the ground level and moving all the way through to evaluation.|
Beyond the tools described in Table 1, more states are moving toward using a systemic approach to roadway safety. This approach involves implementing low-cost, proven improvements based on high-risk roadway features correlated with specific severe crash types (e.g., installing shoulder rumble strips to keep vehicles from encroaching on the roadside or designing safer slopes and ditches to prevent rollovers if a vehicle travels off the shoulder). The systemic approach is particularly valuable on local or rural roadways where the traditional site analysis approach is difficult due to limited crash data or dispersed crash locations. This approach looks at crash history on an aggregate basis to identify high-risk roadway characteristics, which can then be used to determine different strategies that might be implemented in a widespread manner to reduce the potential for severe crashes over large sections of roadways.
FHWA is preparing to release guidance in August 2013 on using the new Systemic Safety Project Selection Tool1. Guidance will include a step-by-step process for conducting systemic safety analysis, analytical techniques for determining a reasonable balance between the implementation of spot safety improvements and systemic safety improvements, and a mechanism for quantifying the benefits of safety improvements implemented through a systemic approach.
While each tool is useful in its own right, not all of the tools can be used by all states or localities due to innumerable differences between the states and localities. Differences impacting use of the tools can be categorized as either organizational or geographical in nature. Organizational differences are largely affected by an organization's maturity in collecting/managing data and cultural acceptance of working within a performance management framework when making transportation planning decisions. The geographical differences are primarily impacted by population density, traffic volume, and road type. Again, it is important to note that across these two categories, even those tools that are used most commonly have a diverse set of challenges associated with implementing them, often unique to a particular state or MPO.
An organization's capacity to adopt safety analysis tools and/or performance measures and performance management techniques should be assessed to identify potential issues. Implementation of tools and processes can be inhibited if an organization cannot support the development of metrics, secure stakeholder and staff support, or facilitate analysis and reporting. Some of the organizational capacities required for successful integration of safety analysis tools and performance management practices are described below:
Organizations must first collect good data before they can fully utilize safety analysis tools or performance measures. When using safety analysis tools, it can be a challenge to obtain genuinely useful data. A transportation department cannot realize a tool's full worth without first confirming that all necessary data to use as inputs to the tool are available in the required format.
In support of safety planning, states have been collecting and analyzing crash data for years. However, some states are less advanced when it comes to the collection and analysis of roadway and traffic data to support safety planning. Several resources that can be used to assist states with expanding their data collection processes are discussed in FHWA's Background Report: Guidance for Roadway Safety Data to Support the Highway Safety Improvement Program.
Data availability and collection protocols should be regularly assessed during the early stages of collection. Ongoing assessments help to ensure that all required data is obtainable and accurate. This "data baseline" can fuel an analysis of any data gaps and helps mitigate decision making reliant on poor, misleading, or non-existent data.
The reporting process should clarify the frequency of reporting, roles and responsibilities for report generation, and the intended audience. This ensures that safety, roadway, and traffic data are reported in a manner that supports use of safety analysis tools and processes. The appropriate reporting structure for performance measures should be documented as the performance
measures are being developed or revised by safety planning experts. Using process maps, schedules, or drafting a reporting plan prior to implementation clarifies how the performance measures will be used and enhances reporting processes. Furthermore, efficiencies can be gained by leveraging existing reporting requirements as a platform to share findings and progress. For example, states are already required to provide the National Highway Traffic Safety Administration (NHTSA) with annual reports for 11 core outcome and behavior measures. Reports on goals and progress are included in state Highway Safety Plans and Annual Reports. Some states, such as Washington and Connecticut, provide online quarterly performance reports through their state Department of Transportation (DOT) websites. Other states may choose to provide internal performance reports to transportation executives or lawmakers. However, given the emphasis on increasing transparency in government, states should consider proactively making at least annual performance reports available to the public like NHTSA does with the Highway Safety Plan reports.2
Assessing the characteristics of an organization with regard to its skill level and experience in data collection and analysis is essential to the successful application of most of the tools. It was reported that representatives from states and MPOs feel that staff are not being appropriately trained to use new tools upon their release. In cases where staff and key stakeholders do not have adequate knowledge or experience analyzing or reporting performance data, extensive training should be conducted prior to implementation of any safety planning tool. Furthermore, without proper training, it is difficult to differentiate between what is potentially the most useful tool, or set of tools, and what may otherwise be less effective. This leads to stagnation and prevents innovative processes and practices from taking hold as some states and MPOs feel as if they are being over inundated. Constraints on staff's time are often so burdensome due to various daily demands of the job that unless immediate potential benefits from investing time/resources in researching and learning a new tool are readily available, that tool is often overlooked as an asset to the safety planning process. That is, generally, safety planners are so busy that they do not have the time to take on a new tool and are not properly incentivized to do so.
Organizational willingness is a key variable in planning processes. Counteracting low organizational willingness requires strong leadership; clear mission, vision, and goals; and a well-defined organizational structure. In the absence of these attributes, the adoption of these tools may not be readily accepted by an organization. Impediments to an organization's willingness to embrace new tools include:
Leadership support and ongoing communication activities are critical to overcoming the potential pitfalls outlined above. An organization's senior leadership should approve the final set of tools and communicate to staff their importance. Engagement at all levels of an organization improves the likelihood of adoption and use of the most effective tools in future planning and decision making.
Population density, be it urban versus rural areas, different concentrations of pedestrian/bicycle traffic, or different road types all impact the applicability of each tool. Large urban areas with higher concentrations of bicycles and pedestrians may face a greater number of fatalities within these roadway user groups. These areas are more likely to use the pedestrians and bicycle safety tools than a rural area.
Traffic volume also impacts tool utilization. For example, the Interactive Highway Safety Design Model (IHSDM) was initially designed for rural roads and has only recently expanded to include multilane roadways and suburban/urban arterials. IHSDM's initial focus on rural roads inhibited its early adoption by states that place a greater emphasis on urban roadway data collection and analysis. Similar to the initial release of IHSDM, the U.S. Road Assessment Program (usRAP) may work better for certain types of roads than others. The usRAP Road Protection Score (RPS) protocol that generates risk ratings based on roadway design features is typically documented with video logs. This time intensive method of collecting one-time data is most applicable to county and local road authorities that often do not have sufficient crash data to perform risk analyses.
Although high level performance measures (e.g., fatality rate) are not likely to vary by geographic difference, differences arise when states use varying definitions for crashes involving serious injuries or use unique methods to normalize data (rates per vehicle miles traveled [VMT], per population, per registered driver; proportions of crashes, injuries, or fatalities with some characteristic, such as the proportion of fatalities that are pedestrians). The number of performance measures used also varies widely from state to state. Some states report on as few as 14 measures while other states may report on over 100 measures.3
Variation in the numbers of and types of performance measures are due to any number of considerations. States are better positioned to track and report a mix of performance measures if they have a longer history of collecting safety data and have developed a strong organizational culture. Other states may be in the early stages of refining data collection methodologies or expanding performance measures. Despite different starting points, all states benefit from learning more about available safety analysis tools that can be used in conjunction with a performance management framework to improve safety outcomes. A move toward standardization, either by adoption of similar tools or performance measure best practices, may improve the culture of performance management among state and
local government regardless of demographic differences.
Transportation safety funding comes in two forms: funds specifically designated for safety improvement projects and money designated for other purposes that has a related safety impact. These different funding channels have disparate impacts on how funds are used. Direct safety funding, like Highway Safety Improvement Program (HSIP) funds, usually has specific requirements recipients must fulfill in order to be granted funds. Money not designated explicitly for safety usually does not carry such specific safety requirements.
State DOTs are the recipients of federal safety funds and, for the most part, by means of their own choosing, distribute money to local groups. When funding is not specifically designated for safety, transportation groups may seek alternate methods to maximize safety gains. Although not a tool per se, alternate methods of funding safety projects offer opportunities to advance safety outcomes outside traditional funding channels. This section offers examples of strategies that transportation organizations have taken to fill funding gaps and insert safety considerations into broader transportation projects that are not typically considered safety projects.
Funding opportunities may exist outside of the traditional appropriations or funds distribution process. The Orange County Transportation Authority (OCTA) successfully used the political process to fund transportation projects through a dedicated sales tax approved by the voters of Orange County. Involving transportation users (citizens) in the decision- making process may improve acceptance of new projects paid for through dedicated tax dollars.
Michigan's Department of Transportation (MDOT) set-aside funds have been valuable for the implementation of projects outside of the ascribed equity-based structure. Set-aside funding provides for greater flexibility in implementing projects that correct known problems. When using set-aside funding, organizations must clearly define the project selection criteria. Once defined, this process may work well for funding multiple low-cost, high-priority projects or a few high-cost projects with a higher expected safety impact.
Colorado's Department of Transportation (CDOT) has shown that safety can be implemented in non-safety projects. During the project design phase, CDOT identifies ways to maximize safety on projects not traditionally considered standalone safety projects.
Developing and maintaining databases to house safety, roadway, and traffic data takes time and money. Given that federal and state funding may be limited by economy, and not all transportation project funding includes a safety component, funding innovations and alternate sources of funding may help state and local transportation organizations maximize safety gains. Exploring alternate funding sources and alternatives to incorporate safety in infrastructure projects is especially important when transportation appropriations slow or decrease.
As state DOTs and MPOs enhance their performance management processes, they are better positioned to demonstrate the success of their projects using available analysis tools to link data and results. By showing a clear link between robust data, predictive tools, project selection, and safety outcomes, these transportation organizations may be better positioned to compete for limited funds.
Outside of specific roadway safety projects funded through HSIP, states and MPOs often report difficulties directly addressing roadway safety. A state or MPO may not directly target safety when faced with other pressing priorities, such as roads and bridges in disrepair. In these instances, states and MPOs may be able to integrate safety in construction and maintenance projects not typically considered safety projects. As states seek to achieve their safety goals, safety improvements should be considered as a core element in roadway project planning.
1 Information at: http://safety.fhwa.dot.gov/systemic/
2 NHTSA posts State Highway Safety Plans, State Annual Reports, and Management Reviews/Special Management Information at: http://www.nhtsa.gov/nhtsa/whatsup/SAFETEAweb/
3 NHTSA requires states to set goals and report progress annually on 10 core outcome measures, one core behavior measure, and three activity measures.