Module 1: Fundamentals of Safety
This module describes safety as a discipline within the transportation industry. It is designed to inform transportation planners and practitioners with adequate knowledge of safety and opportunities for incorporating a consideration of safety in all phases of the transportation planning process. The module includes a discussion of identifying the safety stakeholders, legislation, plans and processes, data and analysis methods, and funding.
The goal of safety planning is to reduce fatalities and serious injuries on all public roads. Safety planning is a collaborative and integrated approach that brings together safety partners to leverage resources for a common safety goal. A data-driven safety planning process can identify opportunities to address the safety performance of a roadway.
Transportation safety is a required factor in the planning process and transportation planners are key partners ensuring that safety is an integral component of all planning processes. With knowledge and understanding of safety and safety planning, transportation planners can enhance collaboration, communication, and coordination with their safety specialist partners to achieve the goal of reducing serious injuries and fatalities.
Transportation safety performance is linked to a variety of elements, including roadway design, traffic law enforcement, road user behavior, and emergency response time. Therefore, effective transportation safety warrants a multidisciplinary approach. Over the past 15 to 20 years, safety practitioners have found value in partnering with a variety of other disciplines, such as public health, advocacy groups, universities, and others to more fully engage the community and the public in safety enhancements. The key players differ from State to State and community to community. Safety stakeholders are becoming increasingly adept in recognizing opportunities for partnerships to help attain safety goals and objectives. This section identifies major safety stakeholders and their roles in the safety planning process.
The 4 Es of Safety
To plan for and shape a safer transportation system, agencies typically consider strategies from engineering, education, enforcement, and emergency medical services (EMS) to improve safety outcomes.
Engineering: Engineers play a critical role in identifying and recommending solutions to address safety performance of the transportation infrastructure. Some of their responsibilities may include managing and participating in the development and implementation of a Statewide or regional road safety plan; collecting and managing crash data; analyzing crash data to identify safety issues and projects; utilizing analysis methods, such as network screening, and sharing the results; identifying safety projects and countermeasures; designing improvements; conducting before and after studies; managing roadway improvements; and coordinating safety issues with other Statewide, regional, and local engineers.
Enforcement: Law enforcement personnel generally are responsible for collecting crash data, traffic law enforcement, behavioral safety campaigns, and sharing information with transportation professionals. In the event crashes do occur, law enforcement collect data for crash reports, which provide details on the crash itself, such as the people and vehicles involved and the environmental circumstances. This information is critical to planners and engineers who use it to identify and address safety issues.
Emergency Medical Services: This group includes first responders and paramedics, fire and rescue personnel, law enforcement, Department of Transportation (DOT) personnel, and tow truck operators. Crash survival and injury severity are integrally linked to response time and the medical care received after a crash. EMS personnel understanding of impediments to effect response and recovery can be critical. Emergency responders can provide insights into health and trauma data recorded at the crash scene and updated at the hospital to more accurately report fatalities and serious injuries; advise on emergency responder safety as they work a crash scene; discuss how to collect better data (i.e., blood draws) at the crash scene to understand all the factors involved; and share knowledge on roadway connectivity or other issues, which may hinder rapid emergency response and transport.
Education: Transportation systems users are not always aware of the risks associated with their behaviors. This community may include school teachers and administrators, hospital and emergency medical services personnel, driver education instructors, health educators, advocacy groups, DOTs, Metropolitan Planning Organizations (MPO), State Highway Safety Offices (SHSO), and others. Specific roles differ by agency or group, but the main purpose is to administer, advocate for, and implement safety education programs for all road users.
Key Safety Partner
SHSO: Every State has an SHSO, which is led by a Governor’s highway safety representative (also referred to as SHSO directors and highway safety or 402 coordinators). SHSO staff is responsible for planning and implementing programs to address behavioral traffic safety issues, such as impaired driving, distracted driving, speeding, occupant protection, etc. While engineers typically are focused on infrastructure safety, the SHSO staff address behavioral safety issues, such as impaired driving, occupant protection, speeding, and the safety of vulnerable road users. The combination of roadway and driving behavior represent nearly all of the crash causation factors and demonstrate the importance of a strong connection between the engineering and behavioral areas.
Other Safety Stakeholders
Health Department Personnel: Many State and local health departments have injury prevention programs, which often include efforts to prevent motor vehicle crashes and resulting injuries and fatalities. This stakeholder group can be particularly effective in providing safety data and analysis skills and insights, lessons learned from other public health efforts, public health approaches to transportation concerns, and advice on topics, such as transportation access, walking, biking, and active lifestyles in general.
Safety Advocates: Many States have locally based groups of safety advocates committed to addressing transportation safety concerns and can be effective in driving awareness and change. The groups typically consist of citizens, law enforcement, public health, medical, diverse groups, government, business, civic and service groups, and the general public. Where available and effective, they serve as a useful resource for advocacy, community education, and fund raising.
Tribal Governments: Tribal governments are responsible for the transportation issues and needs of their citizens. Tribal areas usually experience disproportionately high rates of transportation-related fatalities based on population, so it is critical to engage them in the safety planning process.
Planners: State DOT, MPO, local jurisdiction, and Tribal transportation planners have multiple job functions, which may include duties related to safety. Safety responsibilities vary, but general tasks might include participating in safety plan development and implementation; cooperating on Statewide or regional safety-related committees such as emphasis area teams, to discuss and collaborate on safety issues, crash data collection and management, and data analysis tools, such as geographic information system (GIS) crash mapping. Transportation planners may specialize in a specific transportation mode, such as transit, freight, bicycle, or pedestrian. Planners identify existing and future short- and long-range needs, identify projects and programs, help in establishing priorities, and evaluate outcomes. Experience from each of these areas may provide insight on current safety issues and needs, as well as effective methods for addressing them.
Elected Officials: Decisionmakers sometimes serve as powerful advocates for road safety. They may champion safety needs and direct resources towards the most pressing safety issues; attend ceremonies to publicize newly constructed safety projects; and vocalize support for safety efforts, such as a Vision Zero or Towards Zero Deaths campaigns. Some agencies successfully recruit elected officials to participate in safety plan development and implementation as executive committee members.
Reviewing the major pieces of legislation affecting transportation safety provides a historical perspective and a better understanding of current practice in road safety management practices. This action also assists with detecting future trends and needs.
History and Background
Federal transportation highway safety funding eligibility and use requirements are documented in United States Code (U.S.C.), title 23, Highways. Information on Federal Highway Administration (FHWA) programs and plans relevant to safety planning is addressed in chapter 1—Federal-Aid Highways (§101-§181). Chapter 4—Highway Safety (§401-§412) addresses National Highway Traffic Safety Administration (NHTSA) programs and plans. Specific sections are described below.
Early legislation includes The National Traffic and Motor Vehicle Safety Act of 1966 which established the Federal Motor Vehicle Safety Standards (FMVSS) and regulations motor vehicle manufacturers are required to follow, authorized research and development, and expanded the National Driver Register to track individuals whose licenses have been denied, terminated, or withdrawn. The Highway Safety Act of 1966 created a highway safety grant program requiring States to develop and maintain a highway safety program in accordance with uniform standards established by the Secretary of Transportation. The standards have since been replaced by priority program areas. Section 402 of the Act provided funding specifically for the purpose of improving road user behavior and reducing crashes. It became the basic building block for State highway safety programs.
The Acts passed in 1966 established the basis for vehicle and road user behavioral safety programs, but it wasn’t until the Highway Safety Act of 1973 that a Federal mandate for roadway safety was introduced. The 1973 Act established a specific methodology for improving roadway safety from an engineering perspective and required the States to conduct a survey of all hazardous locations; study the contributing crash factors at those locations; conduct a benefit-cost analysis of proposed mitigation strategies; and prioritize improvements based on the results of the benefit-cost ratio analysis.
The Highway Safety Acts of 1966 and 1973 established the foundation for roadway safety management by focusing efforts on the vehicle, the driver, and the roadway. This legislation also further clarified the relationship between the Federal Government and the States—an important component in road safety. The Federal Government establishes program guidelines for investments but States choose projects and priorities within broad program direction; a Federally assisted State delivered program.
During the 1970s and 1980s, Congress established the Motor Carrier Safety Assistance Program (MCSAP) which provides financial assistance to States to reduce the number and severity of crashes and hazardous materials incidents involving commercial motor vehicles (CMV) through inspections of trucks and carriers, and driver regulations. The Federal Motor Carrier Safety Administration (FMCSA) is responsible for providing oversight for the MCSAP programs.
The 1990s brought further changes, the first of which was The Intermodal Surface Transportation Equity Act (ISTEA). ISTEA required States to develop and implement a series of managements systems, including a safety management system (SMS), but the management system provision was made optional in 1995.
In 1998 Transportation Equity Act for the 21st Century (TEA-21) reduced the number of transportation planning priorities to seven, one of which is "safety and security." TEA-21 represents the first time safety was mentioned as a priority transportation planning factor. Prior to TEA-21, safety may have been incorporated into the vision or goals of a State or MPO long-range transportation plan (LRTP), but specific strategies to increase safety were seldom included in Statewide and metropolitan planning processes or documents.
The importance of safety was further heightened by the Safe, Accountable, Flexible, Transportation Equity Act—A Legacy for Users (SAFETEA-LU), which established the Highway Safety Improvement Program (HSIP) as a new "core" funding program. The amended 23 U.S.C. §148, nearly doubled the funds for infrastructure safety, allowed increased flexibility in program funding, and required a focus on results. This program grew out of the former Hazard Elimination Safety (HES) program that focused on addressing safety issues on the highway system and highway-rail grade crossings.
Program requirements included the development of Strategic Highway Safety Plans (SHSP) in consultation with other key State, Tribal, and local highway safety stakeholders and established a number of reporting requirements. A key element of the SHSP is the direct link to the HSIP. Additionally, to ensure the HSIP is implemented in an organized, systematic manner to achieve the greatest benefits, a formalized HSIP process has been established consisting of three components: planning, implementation, and evaluation. Additional detailed information on the SHSP and HSIP is presented later in this module.
Other programs started under SAFETEA-LU include Safe Routes to School, data improvement programs, traffic records systems improvements (23 U.S.C. §408), and increased funding for 23 U.S.C. §402 (highway safety grants) and several other behavior-oriented grant programs. The legislation also included incentive grants and transfer programs, some of which were carried over from TEA-21. Transfer programs move funds from construction funding categories to safety programs when States fail to pass certain laws or implement specific programs. As in the past, road user behavior programs focus for the most part on occupant protection and impaired driving programs.
Current Legislation and Federal Rules
SAFETEA-LU was replaced by Moving Ahead for Progress in the 21st Century (MAP-21), with MAP-21 being followed by the most recent legislation of the Fixing America’s Surface Transportation (FAST) Act. These Acts and the implementing rules require a performance and outcome-based Federal-Aid Highway Program. Transportation performance management helps agencies prioritize needs and align resources for optimizing system performance in a collaborative manner. The specific requirements are outlined below.
Federal Highway Administration Highway Safety Improvement Program
23 U.S.C. §148—Highway Safety Improvement Program (HSIP) describes the requirements for the HSIP and SHSP. The purpose of the HSIP is to achieve a significant reduction in traffic fatalities and serious injuries on all public roads. The Safety Performance Management (PM) Final Rule adds Part 490 to title 23 of the Code of Federal Regulations (CFR) to implement the performance management requirements under 23 U.S.C. §150, including the specific safety performance measure requirements for the purpose of carrying out the HSIP to reduce serious injuries and fatalities on all public roads. The Safety PM Final Rule establishes five performance measures as the five-year rolling averages for: 1) Number of Fatalities; 2) Rate of Fatalities per 100 million vehicle miles traveled (VMT); 3) Number of Serious Injuries; 4) Rate of Serious Injuries per 100 million VMT; and 5) Number of Nonmotorized Fatalities and Nonmotorized Serious Injuries. The Safety PM Final Rule also establishes the process for State DOTs and MPOs to establish and report their safety targets, and the process that FHWA will use to assess whether State DOTs have met or made significant progress toward meeting their safety targets. There are prescribed financial penalties associated with not meeting the safety targets. The Safety PM Final Rule also establishes a common national definition for serious injuries.
Together, these regulations will improve data; foster transparency and accountability; and allow safety progress to be tracked at the national level. They will inform State DOT and MPO planning, programming, and decisionmaking for the greatest possible reduction in fatalities and serious injuries.
The main HSIP components are a SHSP, a Railway-Highway Crossing Program, and a program of safety improvement projects. To obligate HSIP funds, a State must develop, update, and implement an SHSP that identifies and analyzes safety issues and structure a program of projects to correct or improve hazardous road segments, locations, or features. Eligible projects are enumerated in 23 U.S.C. §148(a). Specific requirements for the HSIP include the following:
- A comprehensive, data-driven SHSP with performance-based safety goals and a program of strategies to improve safety.
- A safety data system to perform problem identification and countermeasure analysis on all public roads; adopt strategic and performance-based goals; advance data collection, analysis, and integration capabilities; determine priorities for the correcting safety issues; and establish evaluation procedures.
- HSIP and railway-highway crossing program annual reports describing progress made towards achieving long-term safety outcomes and safety performance targets.
- A subset of Model Inventory Roadway Elements (MIRE) on all public roads to support enhanced safety analysis and project investments. MIRE is a recommended listing of roadway inventory and traffic elements critical to safety management.
23 U.S.C. §402 is known as the State and Community Highway Safety Grant Program. It provides grants to States to improve driver behavior and reduce fatalities and serious injury crashes. 23 U.S.C. §402 supports programs focused on impaired driving, speeding, and other unsafe driving behaviors; school bus deaths and injuries; occupant protection; motorcycle, pedestrian, and bicycle safety; traffic law enforcement; driver performance; traffic records; emergency services; and teen driver programs. The projects and activities are documented in the annual Highway Safety Plan (HSP). Additional detailed information on the HSP is presented later in this module.
The National Safety Priority Programs (23 U.S.C. §405) supports additional programs focused on occupant protection, traffic safety information system improvements, impaired driving, distracted driving, motorcycle safety, graduated driver licensing laws, and nonmotorized safety. States may be eligible for grant funding in each of these program areas. See the
MAP-21 specifies a single application deadline for all highway safety grants and emphasizes the requirement that all States have a performance-based highway safety program designed to reduce traffic crashes and the resulting deaths, injuries, and property damage. The Final Rule for Safety Performance Management requires the State DOTs to report identical targets for the common measures annually, which ensures coordination between the State DOT and SHSO. The HSP and HSIP share four common performance measures, which are the five-year rolling averages for: 1) Number of Fatalities; 2) Rate of Fatalities per 100 million Vehicle Miles Traveled (VMT); 3) Number of Serious Injuries; and 4) Rate of Serious Injuries per 100 million VMT.
States are required to submit their Section 402 and Section 405 consolidated grant application by July 1 of each fiscal year. NHTSA has 60 days to review and approve the consolidated grant application. Once approved, funds are apportioned to the States under the same formula as SAFETEA-LU: 75 percent population and 25 percent road-miles. At least 40 percent of Section 402 funds must be spent by local governments or be used for the benefit of local governments.
More information on the NHTSA programs is available.
U.S.C., title 23-Highways outlines the Federal transportation safety requirements. This section addresses SHSPs, HSIPs, HSPs, Commercial Vehicle Safety Plans (CVSP), and regional/local safety plans. Particular attention is focused on the SHSP because it is designed to serve as the "umbrella" safety plan for all other State, regional, and local safety plans. The process follows basic strategic planning guidelines, which all safety plans are expected to address.
Strategic Highway Safety Plans
A SHSP is a major component and requirement of the HSIP (23 U.S.C. §148). It is a data-driven Statewide-coordinated safety plan that provides a comprehensive framework for reducing highway fatalities and serious injuries on all public roads. An SHSP identifies a State’s key safety needs and guides investment decisions towards strategies and countermeasure with the most potential to save lives and prevent injuries. SHSPs were first required under SAFETEA-LU, which established the HSIP as a core Federal program. The FAST Act continues the HSIP as a core Federal-aid program and the requirement for States to develop, implement, evaluate and update an SHSP that identifies and analyzes highway safety problems and opportunities on all public roads.
An SHSP is developed by the State DOT in a cooperative process with Local, State, Federal, Tribal, and other public and private sector safety stakeholders. It is a data-driven, multi-year comprehensive plan that establishes Statewide goals, objectives, and key emphasis areas and integrates the 4 Es of highway safety—engineering, education, enforcement and emergency medical services. The SHSP allows highway safety programs and partners in the State to work together in an effort to align goals, leverage resources and collectively address the State’s safety challenges.
The Federal SHSP requirements are documented in 23 U.S.C. §148, and additional information is available on SHSP development, implementation, and evaluation practices in the SHSP Final Guidance, The Champion’s Guide to Saving Lives, the Implementation Process Model (IPM), the Evaluation Process Model (EPM), and other relevant supplementary guidance documents and tools. See State SHSPs and noteworthy practices at the Strategic Highway Safety Plan Community of Practice.
Strategic Highway Safety Plan Requirements
DOTs work closely with FHWA division offices to ensure the requirements are adequately met. The Division Offices are responsible for approving the SHSP development process. A selection of SHSP requirements are summarized below:
- Evaluate and update at least once every five years.
- Consult with stakeholders, specifically the State governor’s highway safety representative and highway-rail grade crossing representatives; regional transportation planning organizations and metropolitan planning organizations (MPO), representatives of major modes of transportation, State and local traffic enforcement officials, motor carrier safety program representatives, motor vehicle administration agencies, county transportation officials, State representatives of nonmotorized users, and other major Federal, State, Tribal, and local safety stakeholders.
- Analyze and make effective use of safety data to address safety problem improvement opportunities on all public roads. Include the findings of road safety audits; location of fatalities and serious injuries, locations without an empirical history of fatalities and serious injuries but contain risk factors, rural roads, pedestrian and bicycle fatalities and serious injuries, cost effectiveness, and rail-highway grade crossings.
- Adopt performance-based goals consistent with FHWA safety performance measures and coordinate the goals with other State highway safety (e.g., HSIP, HSP, CVSP, and local road safety plans) and transportation plans and programs.
- Consider the 4 Es of safety (engineering, education, enforcement, and emergency medical services) to determine effective strategies.
- Identify emphasis areas and strategies with the greatest potential to reduce highway fatalities and serious injuries, and focus resources on areas of greatest need.
- Describe the process and potential resources for implementing the strategies in the emphasis areas.
- For more information, refer to the SHSP Final Guidance and the HSIP Final Rule HSIP Final Rule.
The basic approach used to develop a safety plan involves multidisciplinary engagement to develop vision and mission statements; collect, manage, and analyze safety data; identify goals and objectives (performance measures and targets); develop emphasis areas, strategies, and action plans. Steps for implementing and evaluating the plan often are identified during and after the development process. This planning approach is highly transferable and generally followed for the development of most safety plans (e.g., SHSP, HSP, regional, local, and Tribal safety plans). Using SHSP as a model, the basic steps are further described below.
SHSPs generally begin with vision and mission statements. The vision statement provides the overall direction for a SHSP and drives subsequent discussions and decisions related to planning, prioritizing, and programming safety projects. The mission statement provides a general description of how the safety planning process will accomplish the mission.
SHSPs must be developed in consultation with stakeholders. Participants generally include engineers, enforcement agencies, educators, and emergency responders, and outreach to other agencies listed in the Federal requirements. While not required, DOTs often involve the public during SHSP development. To obtain input throughout the planning process, approaches include hosting Statewide and/or regional safety summits, one-on-one meetings with the stakeholders required by Federal legislation, forming a steering committee to oversee the SHSP, online surveys, and committees or working groups for each of the emphasis areas.
SHSPs are required to be data driven and identify safety issues on all public roads, select emphasis areas (i.e., areas where the potential for safety improvement is greatest), develop strategies for affecting the emphasis areas, create action plans for implementing strategies, monitor progress toward goals, measure effectiveness of programs and projects, and direct resources to the areas of greatest need. The Safety Data and Analysis Methods section that follows provides an overview of the types of safety data used for SHSP development. However, the crash data, which are stored in a State database and often maintained by the State DOT, serve as the primary data source used to inform SHSPs. Crash data are made available to State DOT personnel and other agencies through a variety of methods (i.e., specific request, online portal, searchable database, etc.). States continually strive to improve safety data and do so through the Federally required Traffic Records Coordinating Committee (TRCC), the Crash Data Improvement Program (CDIP), the Roadway Data Improvement Program (RDIP), or NHTSA’s Traffic Records Assessments. Once data are collected and analyzed, analysis outputs are used to identify emphasis areas, strategies, and actions, and performance measures and targets.
National Strategy Emphasis Areas
- Safer Drivers and Passengers.
- Safer Vulnerable Users.
- Safer Vehicles.
- Safer Infrastructure.
- Enhanced Emergency Medical Services.
- Improved Safety Management and Data Processes.
Emphasis areas represent the key factors contributing to crashes, which helps stakeholders focus resources on the top priorities. Once emphasis areas are identified, strategies describe general approaches or methods for lowering fatalities and serious injuries, while action steps detail actions for program and countermeasure implementation. To select emphasis areas, some States start with a list of emphasis areas, such as those identified in the Towards Zero Deaths: A National Strategy for Highway Safety and then look at the number of traffic-related fatalities and serious injuries and select those areas with the greatest number. After SHSP completion, stakeholders begin to implement the strategies and actions described in the plan. States approach implementation differently, but a common method is to retain the SHSP steering committee and/or emphasis area teams as implementing structures. The stakeholders meet regularly to provide updates and discuss challenges.
- Towards Zero Deaths.
- A 3 percent per year reduction for the number and rate of fatalities.
- A 1.5 percent per year reduction for the number and rate of severe injuries.
Safety-related performance management helps a State measure and monitor progress on fatalities and serious injuries. The SHSP can support performance management by adopting performance-based goals consistent with the safety measures FHWA established in accordance with 23 U.S.C. §150. In addition to these performance measures, SHSPs may also set performance-based goals and objectives for each emphasis area.
Evaluation is another required SHSP component, and it is an ongoing process beginning when the SHSP is developed and continuing throughout the life of the plan. Evaluation assesses progress toward strategy implementation and meeting SHSP goals and objectives. Most States have mechanisms in place for regularly tracking SHSP implementation and monitoring progress.
Highway Safety Improvement Program
The HSIP is a core Federal-aid program which allocates funds to highway safety improvement projects to reduce the number and severity of crashes. HSIPs must describe the progress being made to implement highway safety improvement projects, assesses the effectiveness of those improvements, and describe the extent to which the improvements have contributed to reducing fatalities and serious injuries on all public roads. Eligible HSIP projects are primarily infrastructure improvements such as intersection safety Improvements, pavement and shoulder widening, geometric improvements, and can include transportation safety planning, data collection, analysis, and improvement, and Road Safety Audits (RSA), for safety purposes. See 23 U.S.C. §142(a) for the complete list. According to 23 CFR 924.15, the HSIP report shall be submitted annually and address all projects implemented with HSIP funds, including local projects and noninfrastructure projects. The HSIP report consists of four parts: program structure, progress in implementing HSIP projects, progress in achieving safety performance targets, and assessment of the effectiveness of the improvements.
Highway Safety Plans
As administered by NHTSA, the HSP is an annual work program that outlines programs and projects, which primarily address behavioral safety issues, such as speeding, impaired and distracted driving, failure to use required safety equipment, motorcyclist safety, and pedestrian/bicycle safety.
The HSP must be data driven, set performance targets for 15 performance measures, include strategies describing how the State will meet its targets, and share successes on how targets from the previous year were met. NHTSA requires States to develop and submit a State Highway Safety Annual Report and coordinate the HSP with the SHSP. Details for the HSP requirements are contained in 23 U.S.C. §1200.10 to §1200.15.
Commercial Vehicle Safety Plan
FMCSA requires States to develop a CVSP as an annual work program. CVSP identifies a State’s commercial motor vehicle safety objectives, strategies, activities, and performance measures. A CVSP must reflect a performance-based program and include 18 items. The planning details are described in 49 U.S.C. §350.105.
Public Transportation Agency Safety Plan
The Federal Transit Administration (FTA) requires Public Transportation Agency Safety Plans, which means public transportation systems operators must develop a safety plan based on the safety management system approach. The planning details are described in 49 CFR §659.19.
Memphis Metropolitan Planning Organization Regional Bicycle and Pedestrian Plan
The Memphis MPO developed a Bicycle and Pedestrian Plan to identify opportunities for enhancing bicycle and pedestrian travel in the region. During the planning process the MPO conducted a crash analysis to ensure current and future bicycle and pedestrian infrastructure becomes safer.
Regional and Local Safety Plans
At the State level, the SHSP is considered the primary safety document; however, MPOs, Tribes, or local jurisdictions may choose to develop safety plans to identify safety issues, needs, programs, and projects for their specific planning areas. These plans should be consistent with the direction and goals of the State SHSP but can elements that are significant to the localized area. The results of crash analysis in these plans can be used to inform and prioritize the selection of transportation projects.
All elements of the SHSP process, from development to evaluation, require States to analyze and make effective use of State, regional, local, and Tribal safety data. Data enable managers to identify safety problems, select appropriate strategies and countermeasures, monitor progress toward achieving goals and objectives, measure strategy effectiveness, identify needed improvements, and direct limited resources to the highest potential for reducing fatalities and serious injuries. Some States identify the need to upgrade, improve, and standardize the traffic records information system as an SHSP emphasis area.
NHTSA requires all States to develop and maintain a TRCC empowered to improve traffic safety data collection, management, and analysis by coordinating the activities of safety data stakeholders and facilitating information sharing across stakeholders. To accomplish the purpose, the States maintain and regularly update a TRCC Strategic Plan, which includes strategies to improve traffic records accessibility and accuracy. TRCCs are responsible for implementing the Model Minimum Uniform Crash Criteria (MMUCC). The committee also reviews and manages revisions to its State Crash Report Form. Contact the State’s TRCC Chair or Coordinator for more information.
States strive to improve the safety data needed to identify priorities for Federal, State, regional, Tribal, and local highway and traffic safety programs. To effectively advance data gathering capabilities, safety stakeholders develop active partnerships with the TRCCs, which are responsible for identifying data system enhancement strategies affecting access to data, as well as its accuracy, reliability, and timeliness. Both FHWA and NHTSA sponsor data improvement programs designed to assess the strengths and weaknesses of State safety data systems and offer expert consultation and recommendations for corrections and other improvements. (FHWA. (October 2012). A Champion’s Guidebook to Saving Lives, 2nd Edition, FHWA-SA-12-034, Washington, DC.)
Types of Safety Data
The primary types of data used to conduct safety analyses include data on crashes, roadway characteristics, and traffic volumes or exposure. Additional data sets often are used to provide information on drivers, passengers, and vehicles; hospital data; injury control (e.g., EMS response time); and citations and adjudications (e.g., driver citation and arrest records). The following section describes common data sources.
Crash data are used to identify the location and characteristics of crashes. A large set of information is collected by law enforcement at the scene of any crash that meets a minimum injury or property damage reporting threshold. Officers use a crash report form to transcribe information about the crash and the vehicles and people involved. Crash report forms vary by State, but generally, information is collected on specific crash data elements outlined in the MMUCC Guideline, which has more than 70 data elements, such as crash date and time, direction of travel before crash, whether occupants were ejected, contributing circumstances, and more. One of the data fields notes the injury level of the persons involved in the crash, which is coded according to the KABCO scale. Table 1 shows the KABCO injury severity scale. Some States use other scales to rate injuries (e.g., the Manual on Classification of Motor Vehicle Traffic Accidents or American National Standards Institute (ANSI) D.16). FHWA and NHTSA have developed a conversion table to convert serious injuries from other scales to KABCO. Crash data are stored in a database, which is managed by the State DOT or a sister agency.
|Suspected serious injury
|Suspected minor injury
|No apparent injury
In addition to State databases, NHTSA maintains the Fatality Analysis Reporting System (FARS), which provides a Nationwide census on all reported fatal crashes and fatalities involving a motor vehicle operating on a roadway when a person involved in the crash dies within 30 days. FARS provides publicly accessible data regarding fatal injuries suffered in motor vehicle crashes. Fatality data are available from 1975 to present. Queries can be conducted for individual States and at the local/Tribal level. FARS data are obtained from various State documents and reports from law enforcement, death certificates, State vehicle registration files, coroners and medical examiners, driver licensing files, hospitals, highway departments, EMS, vital statistics, and others.
The FHWA Roadway Safety Data Program includes tools to build or enhance safety data.
Roadway characteristics refer to the information that describes the physical attributes and conditions of the street network. All States have a roadway inventory database managed and maintained by the State DOT. This information is useful to transportation planners and safety practitioners because crashes can be associated with road attributes, such as functional class, number of traffic lanes, speed limits, and average daily traffic. Safety specialists may collaborate with transportation planners to understand the uses of roadway data, brainstorm opportunities to pair the data with other data sets, and determine specific plans and corridor studies where roadway data are needed. When roadway data are linked with crashes, planners are able to characterize crashes by roadway features (i.e., number of crashes per year by roadway functional class, number of traffic lanes, speed limit). The HSIP Final Rule (23 CFR 924) requires States to collect and use MIRE Fundamental Data Elements (FDE) on all public roads to support enhanced safety analysis and safety investment decisionmaking. The HSIP Final Rule establishes three categories of MIRE FDEs based on functional classification and surface type. States must incorporate specific quantifiable and measureable anticipated improvements for the collection of MIRE FDEs into their Traffic Records Strategic Plan by July 1, 2017 and have access to the complete collection by September 20, 2026.
State DOTs are required to collect and submit traffic counts data on public roads classified as National Highway System (NHS) routes and all other roads, excluding those functionally classified as minor collectors in rural areas and local roads in any area through FHWA’s Highway Performance Monitoring System (HPMS). Understanding the correlation between crashes and traffic volumes helps planners develop methods to calculate crash rates for segments or intersections and prioritize locations for improvement. The HPMS provides a source of information for VMT and can be utilized to calculate the required fatality and serious injury rates.
Additional data sets used to understand safety issues and needs include data on citations and adjudications, hospitals and traumas, vehicles, and driver/passenger information. Citation and adjudication data refer to driver arrest and conviction records for traffic offenses; injury data includes prehospitalization and hospital information regarding injuries, which may differ from the crash report; vehicle data provides information on vehicle safety technologies, as well as vehicle type (i.e., passenger vehicles, commercial motor vehicles); and driver and passenger data reflect human behaviors contributing to a crash.
Safety Analysis Methods and Tools
A number of approaches and tools are used to analyze safety data. Quantitative safety analysis assists with integrating safety performance into highway investment decisions. This section summarizes the common factors and methods used to analyze safety data, and introduces quantitative safety analysis tools. It provides an understanding of safety analysis applications in the safety management process.
An examination of nominal safety versus substantive safety is key to understanding the importance of safety analysis. Nominal safety refers to the design elements meeting all of the design criteria or standards for a roadway. Substantive safety refers to the safety performance (i.e., crash history relative to crash expectations) for a roadway. It is important to understand that substantive safety (safety performance) of a roadway does not always correlate to the nominal safety (design standards) of the roadway. It is not uncommon for a roadway to meet design criteria but at the same time demonstrate poor safety performance. Safety analysis moves beyond the concept of nominal safety to the advantage of examining safety performance.
Most agencies with safety responsibility commonly conduct basic analyses to determine crash frequency, severity, rates, contributing factors, and types to determine priority projects and programs associated with the greatest potential for reducing fatalities and serious injuries. Frequency is the number of crashes occurring within a specific jurisdiction on a roadway segment, or at an intersection while severity describes the extent to which persons are injured or killed in the incident. This is useful to safety practitioners because locations with more severe crashes are typically prioritized; however, this approach only takes into account injury severity without attention to the roadway, vehicles, human factors, etc.
Rate compares crash frequency with traffic volume or exposure data. Safety practitioners use crash rates to assess safety of roadways, segments, and intersections compared to other similar facilities. Locations with crash rates higher than the Statewide average are prioritized as resources become available. However, careful examination of crash rate is required as an increase in traffic volume without a decrease in crash can produce misleading results of safety improvement. Contributing factors include attributes, such as driver behaviors, events, and roadway infrastructure characteristics. Most crashes have more than one contributing factor. Crash type describes the manner of collision, such as rear-end, sideswipe, head-on, fixed object, pedestrian, overturned, run off the road, etc. Safety practitioners usually assess and prioritize overrepresented crash types.
The Highway Safety Manual (HSM) presents an overarching science-based approach to safety management and a variety of predictive analysis tools for quantitatively estimating crash frequency or severity at a variety of locations. This approach provides for a quantitative information-based decisionmaking process. The HSM is divided into four parts: Part A provides an introduction to the HSM, knowledge about human factors, and the fundamentals of highway safety; Part B covers the roadway safety management process; Part C introduces predictive methods for different facility types; and Part D provides information on the development and use of crash modification factors (CMF). The effects of implementing countermeasures, geometric or operational changes to the roadway can be quantified as a CMF.
The HSM methodologies advance beyond the limitations of the basic safety analysis approach of assessing frequency, severity, and rate. Instead, the HSM provides a substantive safety approach referring to the actual or expected safety performance of a roadway based on its characteristics. Examples of the HSM methods include predictive analysis, systemic analysis, and network screening.
Predictive analysis uses safety performance equations known as safety performance functions (SPF) to estimate predicted average crash frequency as a function of traffic volume and roadway characteristics. This information can be used to compare and predict safety performance, and quantify the safety impacts of transportation decisions.
Systemic analysis examines crash history on an aggregate basis to identify high-risk roadway characteristics, such as sharp curves combined with high traffic volumes, sharp curves and narrow shoulders, etc. Subsequently, low-cost solutions and countermeasures are implemented on a systemwide basis. Systemic improvement examples include installing cable median barriers, rumble strips and stripes, guardrail, the safety edge, and shoulders on narrow two-lane roads; rehabilitating and/or upgrading traffic control devices, pavement marking, surface friction, and lighting; widening lanes and shoulders. FHWA provides a number of resources relevant to systemic analysis on the Systemic Approach to Safety Web site.
Network screening analysis pinpoints roadway segments and intersections experiencing more crashes than would be expected for comparable sites. From this analysis, safety practitioners identify specific locations that may benefit from safety improvements and, with more detailed analysis, the specific modifications for any given site. Information in the Improving Safety on Rural Local and Tribal Roads Safety Toolkit provides additional information on network screening.
All States must have a highway safety improvement program which uses a roadway safety management process; the HSM Part B contains a process for conducting network screening which could serve as a model. Safety practitioners often utilize Part C, Predictive Methods, because it helps evaluate the expected crash frequency for design alternatives associated with corridor or intersection planning projects.
The FHWA Every Day Counts (EDC) effort provides resources to practitioners on a variety of innovative tools and processes. As an example, the Data-Driven Safety Analysis (DDSA) initiative builds on decades of work and collaboration among the various entities in the transportation community to promote the broader implementation of quantitative safety analysis. It has become an integral component of safety management and project development decisionmaking. The effort has inventoried tools agencies can use for safety analysis. The following paragraphs summarize some examples of those tools.
The EDC-3 Data-Driven Safety Analysis Web site provides a list of analysis tools practitioners can use to inform decisionmaking and optimize investments. These tools include:
- AASHTOWare Safety Analyst—a set of software tools used by State and local highway agencies for network screening and countermeasure identification.
- FHWA Interactive Highway Safety Design Model (IHSDM)—a suite of software analysis tools for evaluating safety and operational effects of geometric design decisions on highways.
- CMF Clearinghouse—a regularly updated online repository of the CMFs used to forecast the impact of a countermeasure on crash frequency and severity.
- FHWA Systemic Safety Project Selection Tool—tools for selecting locations and countermeasures, achieving the correct balance between systemic and traditional safety investments, and evaluating effectiveness.
- Roadway Safety Data Program Toolbox—online tool used to identify data collection analysis and management resources.
The HSIP, NHTSA grant funding, and FMCSA safety grants are the primary Federal-aid safety funding sources available for infrastructure and behavioral safety improvements. However, funding from other Federal, State, and local programs is used to implement safety projects and programs.
The HSIP is a core Federal-aid program managed by FHWA. Its purpose is to reduce the number of fatalities and serious injuries on all public roads. The HSIP includes three components: the SHSP, a Railway-Highway Crossing Program, and a program of safety improvement projects. To identify and prioritize eligible projects, States are required to utilize a safety data system with the ability to perform safety problem identification and countermeasure analysis.
NHTSA manages the primary funding for HSP projects and programs. The funding comes from 23 U.S.C. §402 (State and Community Highway Safety Program) and 23 U.S.C. §405 (National Priority Safety Programs) grant programs. The programs provide grants to States to improve driver behavior and reduce fatalities and serious injury crashes. 23 U.S.C. §402 funds can be used on a wide array of countermeasures identified in the HSP, including programs that reduce impaired driving or speeding, encourage the use of seat belts, improve motorcycle safety, improve pedestrian and bicycle safety, reduce school bus deaths and injuries, reduce crashes from unsafe driving behavior, improve enforcement of traffic safety laws, improve driver performance, improve traffic records, to implement teen driver programs, and enhance emergency services.
23 U.S.C. §405 grants support specific behavioral programs: §405(b) addresses occupant protection, §405(c) is for improving traffic safety information and data systems, §405(d) is for impaired driving and ignition interlock laws, §405(e) is for distracted driving, §405(f) is for motorcycle safety, §405(g) is to encourage graduated drivers licensing programs, and §405(h) is for nonmotorized roadway user programs.
FMCSA offers a number of safety grants for commercial motor vehicle activities. The grants are available for border enhancements, commercial driver license program implementation, CMV operator safety training, commercial vehicle information systems and networks, motor carrier safety assistance program (basic and high-priority grants), new entrant safety audits, performance and registration information systems management, and safety data improvements.
Additional funding sources include 23 U.S.C. §1106 National Highway Performance Program (NHPP) projects, which must be on an eligible facility and support progress toward achievement of national performance goals for improving infrastructure condition, safety, mobility, or freight movement on the National Highway System (NHS) and be consistent with metropolitan and Statewide planning requirements.
The Surface Transportation Block Grant Program (STBG), administered by FHWA (23 U.S.C. §133), lists eligible projects, such as "highway and transit safety infrastructure improvements and programs, installation of safety barriers and nets on bridges, hazard eliminations, projects to mitigate hazards caused by wildlife, and railway-highway grade crossings." STBG has the most flexible eligibility requirements among all Federal-aid highway programs.
Transportation Alternatives, administered by FHWA (23 U.S.C. §133(h), eliminated the Transportation Alternatives Program (TAP) and replaced it with a set aside of STBG funding. These grants support a variety of smaller-scale transportation projects, such as pedestrian and bicycle facilities, recreational trails, safe routes to school projects, community improvements such as historic preservation and vegetation management, and environmental mitigation related to storm water and habitat connectivity.
State funding from taxes, or other funding sources, sometimes are leveraged to support transportation improvements. For examples, in Iowa, the Traffic Safety Improvement Program provides State safety funds to Iowa cities, counties, and the Iowa DOT for site-specific countermeasures, traffic control devices, and research.
Safety practitioners analyze data, assess countermeasures, estimate cost benefit, and select and prioritize projects with respect to both safety and general transportation projects with safety components. Meaningful improvements to safety performance on the transportation network warrant collaboration, coordination, and communication among many disciplines. The safety planning process includes the development of the SHSP, HSP, HSIP, CVSP, and the integration of safety into transportation plans. The goal is to identify a combination of behavioral and infrastructure approaches to most efficiently and effectively reduce fatalities and serious injuries. Safety practitioners from the 4 Es are active participants in the safety planning process, but transportation planners also can become engaged to shape safety considerations for transportation infrastructure. The following module focuses on the transportation planners; roles, responsibilities, and opportunities for improving the safety of the nation’s roadways.
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