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With almost 20,000 lane miles on the Oregon highway system, the Oregon Department of Transportation (ODOT) is responsible for managing and maintaining its roadway assets. Managed assets include barriers, traffic signals, lighting, pavement markings, and signs. ODOT has developed an inventory of its assets and evaluates asset condition in order to efficiently manage maintenance efforts. Over several years, ODOT implemented two new programs to manage their roadway assets, TransInfo and the Features, Attributes, and Conditions—Statewide Transportation Improvement Program (FACS-STIP) Tool. TransInfo is a statewide asset management system. It provides ODOT asset management staff with the most up-to-date statistics on assets and other features on the State highway system. The FACS-STIP Tool is a web-based program that provides information on an asset’s location, attributes, and condition to all users with internet access.
While many states have made significant strides towards the inclusion of all public roadways in their Highway Safety Improvement Program (HSIP) efforts, an evident disconnect often exists between the quality of safety data used for state-owned and local roadways. Whether due to budget restraints or a lack of proper channels to share information, state-level HSIP decision-makers are frequently forced to make programming decisions for local roads based on incomplete or inadequate data. Where local safety data is available, local roadways are still at a disadvantage due to the additional effort required to procure and process data outside of the statewide system.
The Rhode Island Department of Transportation (RIDOT) recently identified some of these issues within their own HSIP processes. They recognized that they needed to take a planned, stepwise approach to address these challenges, one that began with better location data for local roads. Specifically, only a portion of their local roadways were included in the same Linear Reference System as their state-owned roadways. This includes local roadways that were absent in the referencing system in the HSIP process and that required a time-consuming manual review that was subject to human error and interpretation. Although they were able to accommodate all roadways the State's HSIP, significant RIDOT staff efforts were required.
RIDOT is making a concerted effort to include all public roads in the State's Linear Referencing System to respond to this challenge and build a more comprehensive database for safety analysis. In addition, work is being done to collect data for every roadway in the State using the Model Inventory of Roadway Elements (MIRE). Not only will this enhance RIDOT's ability to accurately conduct advanced safety analysis, but it will also expand their data support to local governments. Together, these improvements to the statewide and local databases will ultimately result in more informed and effective decision-making.
To complement this analytic capability, RIDOT is also expanding their HSIP program to increase local government participation. Specifically, they are developing a local safety program that will provide training and resources to municipalities for making data-driven decisions. In addition, the State is establishing a dedicated fund for local projects/programs and providing municipalities with templates for proposing low-cost improvements for HSIP funding.
Key Accomplishments
RIDOT is implementing a long-term plan to help local governments understand the importance of good data in improving safety.
RIDOT has started collecting data for all public roads in the state to enable both the State and locals to use advanced safety analysis methods in the future.
To support local priorities, RIDOT is also developing training and technical resources to assist municipalities in making data-driven decisions.
Results
RIDOT is making a long-term investment in improving data for all public roads in the State and, in so doing, build a much stronger foundation for analytic safety decision-making. As a first step, RIDOT is including all roads in the State's Linear Referencing System and is collecting MIRE data for those roads, helping level the playing field for local governments and providing them with a pathway to compete for HSIP funding. This stepwise approach also ensures that the RIDOT can direct HSIP funds where it can contribute the most to reducing fatal and serious injury crashes, regardless of who owns and operates that part of the State's roadways system.
Contacts
Sean Raymond, P.E.
HSIP Program Manager
Rhode Island Department of Transportation
Two Capitol Hill
Providence, RI, 02903
(401) 222-2694 ext. 4204
Fax: (401) 222-3006
Robert Rocchio, P.E.
Managing Engineer
Traffic Management
Rhode Island Department of Transportation
Two Capitol Hill
Providence, RI 02903
(401) 222-2694 ext. 4206
Fax: (401) 222-3006
Crash data remains a fundamental component of virtually any safety analysis. States use it to identify spot safety improvements, screen for systemic safety improvements, diagnose specific safety concerns, select countermeasures, and justify HSIP investments. But which crash data should States use? And how should they consider the severity of a crash when making safety decisions?
Since the passage of Moving Ahead for Progress in the 21st Century Act (MAP-21), States have placed greater focus on measuring safety performance, particularly in reducing the number and rate of traffic fatalities and serious injuries. This increases the focus on crashes most severely impacting society and human life while reducing the significance given to crashes resulting only in property damage or minor injury. States have worked to accommodate these changes in their Strategic Highway Safety Plans (SHSP) and are also finding ways to place greater emphasis on fatal and serious injury crashes throughout their HSIP processes.
States most commonly use the “KABCO” severity scale, developed by the National Safety Council to measure the observed injury severity for any person at the scene of a crash, to classify the severity of roadway injuries. The Fourth Edition of the Model Minimum Uniform Crash Criteria codes crashes as Fatal Injury (K), Suspected Serious Injury (A), Suspected Minor Injury (B), Possible Injury (C), and No Apparent Injury (O). Many States have interpreted “fatal and serious injuries” as including just “KA” or “KAB” injuries, and the most aggressive States only use data for these crashes in all aspects of their safety analysis.
As an example, the Virginia Department of Transportation (VDOT) gives highest improvement considerations to locations that have experienced “K” and “A” injuries. They develop statewide listings and maps of high crash routes and intersections following the SHSP Emphasis Areas. VDOT's central office provides these to district staff to identify candidate locations for project development, including intersections ranked by Deaths (type “K”) plus Severe Injuries (type “A”) in the most recent three years within each jurisdiction. Those locations in the top 5% are first priority. Those between the top 5% and 15% are second priority, and the remainders are lower priority.
Other States primarily use fatal and serious injury crash data, but also apply broader ranges of crash data and different screening criteria for certain crash types. For example, the Illinois DOT uses “all crashes” in their identification of high-risk horizontal curves, one of their SHSP priority emphasis areas. However, they use “all crashes” as part of the Highway Safety Manual (HSM) methodologies to identify curves where the observed crash frequency exceeds the expected frequency (calculated using the State's safety performance functions [SPFs]), or where there exists an excess proportion of specific crash types.
A third approach used by many states utilizes a weighted severity index or Equivalent Property Damage Only (EPDO) methodology, in which crashes are given different, pre-determined values depending on their severity. For example, a property damage only (PDO) crash may only have a value of one, but an incapacitating injury crash may have a value of 10. This would effectively give a crash with a category “A-injury” ten times the weight of a crash with no injury. In the Maryland DOT, this kind of weighting system is used to identify Critical Safety Improvement Locations (CSILs) and prioritize them for review and improvement. Figure 2 provides the weights Maryland uses when calculating their CSIL list. Although the system does not dismiss less severe crashes, it gives much higher weight to intersections and segments that have more serious injury crashes.
Finally, States also place greater weight on fatal and serious injury crashes in their analysis by either using dollar amounts to document the costs and benefits or limiting their analysis to only fatal and serious injury crashes. In addition, some states focus on countermeasures that have a particular effectiveness in preventing some of the most serious crashes (e.g., cable medial barrier to prevent cross-over head-on collisions).
Key Accomplishments
Safety issues posing the greatest risk of fatal and serious injury crashes receive higher priority
States place greater emphasis on investments to reduce the most serious crashes
Results
States are shifting away from simply focusing on reducing crashes and toward identifying the best opportunities and countermeasures for reducing crashes resulting in fatalities and serious injuries. This contributes to HSIP funding decisions that move states closer to achieving the national goal in MAP-21 “to achieve a significant reduction in traffic fatalities and serious injuries on all public roads.”
Contacts
Tracy L. Turpin
Highway Safety Improvement Programs Manager
1401 E. Broad St., Room 207
Richmond, VA 23219
(804) 786-6610 Tracy.Turpin@VDOT.Virginia.gov
William (Bill) Macleod
Maryland State Highway Administration
707 North Calvert Street
Baltimore, Maryland 21202-3601 WMacleod@sha.state.md.us
One of the key challenges every state faces in addressing its safety issues is the availability of timely and accurate crash data. The Moving Ahead for Progress in the 21st Century Act (MAP-21) made this even more apparent by requiring states to establish safety performance targets for reducing fatalities and serious injuries on all public roads. In Florida, the Strategic Highway Safety Plan (SHSP) provides the roadmap for achieving those targets and integrating safety initiatives in all emphasis areas. The SHSP also makes it very clear that achieving these targets will require actions on both the state highway system and on roadways owned and operated by local governments and agencies. Over 25% of the State's roadway fatalities occur on local roads, and this number points to the tremendous challenge of addressing roadway safety issues on Florida's local roads.
To address safety challenges on local roads, the Florida Department of Transportation (FDOT) is working via their Traffic Records Coordinating Committee (TRCC) to interact with over 300 local agencies throughout the State, including law enforcement, health care, and emergency medical service agencies. The key goals of the TRCC are to integrate data systems across agencies, and promote the timeliness, accuracy, completeness, and uniformity of data collected. In recent years the TRCC funded local agencies to improve their ability to collect and store enforcement actions and crash data. Specifically, local agencies used the funding to purchase hardware to support their reporting capabilities.
eCitation and eCrash are electronic citation software that allow law enforcement officers, at the scene of a crash, to use laptops in their police vehicles to input data and information from a traffic incident directly into a computerized database. These systems also have scanners, which transfer driver's license information directly to forms, reducing errors.
In addition, Florida recognizes that in order to move beyond using historical crash data alone to make countermeasure choices, certain core roadway data elements will be required for all roads in the State. This has been a challenge for many local jurisdictions. The FDOT is working with localities to develop databases that can be merged with crash data to better prioritize safety needs on local roads.
Overall, locals are seeing the benefits that come from having better data. In 2013, nearly $38 million in Highway Safety Improvement Program (HSIP) funds went to local safety projects (only $9.2 million was obligated for local safety projects in the previous year). In addition, the State has made a considerable commitment to assisting locals in planning, evaluating, and preparing justifications for such projects.
Key Accomplishments
Through their Traffic Records Coordinating Committee, the Florida DOT provides assistance to over 300 local agencies in improving their data systems.
The State's new eCitation and eCrash systems ensure timely and accurate data collection from law enforcement and first responders.
Local agencies received funding to purchase hardware to optimize application of these new data systems.
Results
Data is the foundation of sound safety decision-making, and the FDOT recognizes the importance of having that data for all roads in the State. By engaging and providing resources to local governments, the FDOT is better able to support and target their safety initiatives, and integrate their efforts into achieving the State's overall safety goals.
Contact
Ms. Danielle King
TRCC Coordinator
Florida Department of Transportation
Traffic Safety Management Office
605 Suwannee Street, MS 53
Tallahassee, FL 32399
(850) 414-4226 Danielle.King@dot.state.fl.us
Describe the roadway safety situation or state before the new practice was implemented. What was the safety issue, problem, or gap?
For years, Illinois county engineers wanted access to crash reports for their studies. State legislation was changed to include local governmental agencies, but they still had to sign an inter-governmental agreement with the Illinois Department of Transportation (IDOT) to receive the reports.
What were the key challenges that needed to be addressed before the new practice could be implemented?
The existing legislation 625 ILCS 5/11-408 of the Illinois Vehicle Code states:
“Upon request, the Department (IDOT) shall furnish copies of its written accident reports to Federal, State, and local agencies that are engaged in highway safety research and studies. The reports shall be for the privileged use of the Federal, State, and local agencies receiving the reports and shall be held confidential.”
As a result, the inter-governmental agreement was required to access the data.
Describe the new practice.
The Safety Portal was developed and launched in August 2014 to allow Illinois local government entities to view their crash reports. This project includes various tools that provide crash report(s) search capabilities, Geographic Information Systems (GIS) mapping for identified crash reports, on-line training materials for law enforcement agencies, and predefined crash data summary reports. The target end users for the Safety Portal include IDOT staff; National Highway Traffic Safety Administration (NHTSA) representatives; Federal Highway Administration (FHWA) representatives; Federal Motor Carrier Safety Administration (FMCSA) representatives; Illinois County Engineers and staff; Metropolitan Planning Organizations in Illinois; and state, county, and local law enforcement agencies.
The Safety Portal is one place all these entities can now view Illinois crash reports and data summaries without signing agreements with IDOT. End users do, however, have to agree to comply with a Confidentiality Statement before they can gain access to the Safety Portal. For end users to gain access to the Safety Portal, they must be approved by a “Vetter.” Vetters are people who have the authority to approve individuals from their respective agencies/jurisdictions for access into the Safety Portal.
List the key accomplishments that resulted from the new practice. Include the roadway safety improvements.
As of the beginning of calendar year 2015, IDOT had received 599 Vetter Registration forms from law enforcement agencies, county highway departments, IDOT, FHWA, and FMCSA.
A total of 520 users were registered and approved for access to the Safety Portal. Of those, 85 are with IDOT, 351 are with law enforcement agencies, 81 are with county engineers, 2 are from the FHWA, and 1 is from the FMCSA.
As of April 3, 2015, there are 869 registered end users. This number continues to climb each week.
What technical and/or institutional changes resulted from the new practice?
The Safety Portal allows users to obtain important crash information. The tool eliminated the need for agencies to sign inter-governmental agreements.
What benefits were realized as a result of the practice?
The former Chairman of the County Engineers Safety Committee indicated their membership feels the Safety Portal is an excellent tool that advances their ability to access critical data and crash reports for their counties. They are excited to have all 102 of their Association members registered, along with their respective staff.
IDOT has also received feedback from local Chiefs of Police indicating this tool will be invaluable for their search of historical records. One Chief commented that now he will not have to dig through old filing cabinets to find crash reports from three to five years ago, instead he has simple access to them through the Safety Portal.
Summary from Crash Modification Factors in Practice: Using CMFs to Quantify Safety in the Value Engineering Process
(The Missouri case study begins on Page 22 of the full report, after background information about the use of crash modification to quantify safety in the value engineering process.)
Background
The following case study illustrates how the Predicted Crash Frequency with CMF Adjustment method has been used to explicitly consider the safety impacts of opportunities during the Value Engineering (VE) process. Specifically, it focuses on the quantification of safety in the evaluation phase when safety is a project factor and crash frequency is the related performance measure. Information for the case study was provided by the Missouri Department of Transportation (MoDOT).
MoDOT integrates data-driven decision-making in many of their planning and design practices, including the VE process. While not part of their VE policy, MoDOT encourages the use of the AASHTO Highway Safety Manual to better understand the safety implications of design-related decisions.
Project Description
MoDOT Southeast District proposed a roadway improvement project on a rural, two-lane section of Route 34 in Bollinger County, MO. The existing 2.8-mile study section is characterized by a narrow cross-section with several horizontal curves and relatively unforgiving roadside. The proposed project involved resurfacing, lane and shoulder widening, horizontal realignment, installation of centerline rumble strips, and roadside improvements. The project was also listed on the district's VE work plan, which is created by the District Value Engineering Coordinator (DVEC) to identify priority projects for VE study. Suggested selection criteria are provided at the following link to aid the DVEC in selecting projects for the VE work plan: http://epg.modot.org/files/c/c0/130_VE_Project_Selection_Criteria.doc.
Findings
Safety Performance Function (SPFs) can be used to predict crashes for baseline conditions and CMFs can be applied to adjust the baseline estimate to reflect specific conditions of interest. This is useful for quantifying and comparing the safety performance of scenarios with different design features and can aid in the decision-making process. Specifically, this approach can help an agency to better understand the potential safety impacts of individual design elements and changes proposed as part of a VE study when safety is a project factor and crash frequency and/or severity is the performance measure. In this case, Southeast District of MoDOT used the Predicted Crash Frequency with CMF Adjustment in order to quantify the safety impacts of road widening in conjunction with horizontal realignment, centerline rumble strips, and roadside improvements. Two alternative alignments (original proposed design and VE proposed design) were compared to the existing conditions. While the two alternative designs provide nearly identical levels of safety based on total predicted crashes, the VE proposed design would reduce project costs. The use of the Predicted Crash Frequency with CMF Adjustment demonstrated that the proposed improvements could result in a substantial reduction in crashes compared to existing conditions. It also showed that the VE proposed design would provide a similar level of safety to the original proposed design while providing additional benefits. Recall that non-calibrated SPFs may overestimate or underestimate the predicted crash frequency, but provide a reasonable estimate of the percent difference in crashes among alternatives. As such, it is desirable to use a calibrated SPF if it is necessary to estimate the change in predicted crash frequency or conduct a formal economic analysis.
(The case studies begins on Page 18 of the full report, after background information about the use of crash modification to quantify the safety performance of design decisions and exceptions.)
Background
Crash Modification Factors (CMFs) can be applied in the development and analysis of alternatives to estimate the safety performance when the advantages and disadvantages of each alternative are considered. The following case studies illustrate how CMFs have been applied by the California Department of Transportation (Caltrans) and the Missouri Department of Transportation (MoDOT) in the development and analysis of alternatives.
Case Study #1: California
The following case study illustrates how the Observed Crash Frequency with CMF Adjustment method has been used to assess the safety impact of individual design elements and evaluate the overall impact of design exceptions on the safety performance of a facility. Information for the case study was provided by Caltrans.
Project Description
In response to 24 collisions that occurred in a three-year period within a section of US 199 in Northern California, District 1 of Caltrans proposed a series of engineering improvements to address potential safety issues. The project limits are within United States Forest Service Lands in Del Norte County, approximately two miles north of Hiouchi. The limits extend from 0.9 to 1.1 miles north of South Fork Road. The existing alignment consists of two curves with a short tangent transition, forming a reverse curve. Curve 2 was the primary focus of the engineering improvements as all 24 crashes occurred along this curve during the three-year period.
Findings
CMFs can be applied to quantify the safety impacts of design elements and estimate the effects of mitigation measures. Combined, these results can be used to evaluate the overall impacts of design exceptions on the estimated safety performance of a facility. In this case, District 1 of Caltrans used CMFs in order to quantify the safety impacts of increasing the radius of a curve, increasing the superelevation, increasing the width of the travel lane, and increasing the shoulder width. Even though some of the proposed changes did not meet the design standard based on California's design documents, the use of CMFs demonstrated that the proposed improvements could result in a substantial reduction in crashes compared to the existing conditions. Further analysis could compare the estimated safety impact of proposed design exceptions with respect to design standards. The results of the safety analysis could also be considered in conjunction with other factors such as project cost, operational performance, and environmental impacts.
Case Study #2: Missouri
The following case study illustrates how the Predicted Crash Frequency with CMF Adjustment method has been used to assess the safety impact of individual design elements and evaluate the overall impact of design exceptions on the safety performance of a facility. Information for the case study was provided by the Missouri Department of Transportation (MoDOT).
Project Description
MoDOT Central District proposed a project on a rural, two-lane section of Route 42 in Kaiser, MO. The existing conditions included a narrow cross-section with lane widths of 10.5 feet and unpaved shoulders. The proposed conditions included paved shoulders (2 feet in both directions) and shoulder and centerline rumble stripes. The design guidelines for minor roads in Missouri identify minimum expectations for several design features, including a consistent shoulder width of 2 to 4 feet. In this case, the District conducted an analysis, using Part C Predictive Methods of the HSM, to document the potential safety benefits of the proposed conditions compared to the existing conditions. A separate analysis is also provided to compare the safety performance of different shoulder widths (2 feet versus 4 feet).
Findings
SPFs can be used to predict crashes for baseline conditions and CMFs can be applied to adjust the baseline estimate to reflect specific conditions of interest. This is useful for quantifying and comparing the safety performance of scenarios with different design features and can aid in the decision-making process. Specifically, this approach can help an agency to better understand the potential safety impacts of individual design elements and design exceptions. MoDOT conducts similar safety analyses as part of the evaluation of design exceptions that involve safety related features. In this case, Central District of MoDOT used the Predicted Crash Frequency with CMF Adjustment method in order to quantify the safety impacts of installing a paved shoulder with shoulder and centerline rumble stripes. Two different scenarios are compared to the existing conditions. The proposed condition included a paved shoulder width of two feet, while the alternative condition based on design guidelines is a paved shoulder width of four feet. The use of this quantitative method demonstrated that the proposed improvements could result in a substantial reduction in crashes compared to existing conditions. Recall that non-calibrated SPFs may overestimate or underestimate the predicted crash frequency, but provide a reasonable estimate of the percent difference in crashes among alternatives. As such, it is desirable to use a calibrated SPF if it is necessary to estimate the change in predicted crash frequency or conduct a formal economic analysis.
(The case studies begins on Page 17 of the full report, after background information about the use of crash modification development and analysis of roadway safety alternatives.)
Background
Crash Modification Factors (CMFs) can be applied in the development and analysis of alternatives to estimate the safety performance when the advantages and disadvantages of each alternative are considered. The following case studies illustrate how CMFs have been applied by the Colorado Department of Transportation (CDOT) and the Arizona Department of Transportation (ADOT) in the development and analysis of alternatives.
Case Study #1: Colorado
The following case study illustrates how the Observed Crash Frequency with CMF Adjustment method has been used to assess the safety impact of alternatives. Information for the case study was provided by CDOT.
Project Description
Castle Rock, Colorado lies south of Denver along the Interstate 25 corridor. To accommodate growing development in the area, CDOT considered a new interchange on I-25. In addition to the “no build” scenario, they considered two alternatives for the new interchange design. Alternative 1 would extend one road, Castlegate Drive, to create the new interchange. Alternative 2 would extend another road, Atrium Drive, to create the new interchange.
As part of the environmental assessment of the project in 2009, CDOT conducted a safety analysis to evaluate the effect on crashes for the proximate roadway segments and intersections, including ramp junctions. The full safety analysis developed estimates of crash predictions for each segment and junction based on either Safety Performance Functions (SPFs) (for segments) or comparisons to similar intersections in the area (for intersections). At the time of the analysis, CDOT did not have available SPFs for intersections.
Findings
This case study presented an example of how CMFs can be applied to estimate the safety impacts of various alternatives. The safety analysis presented in this case study was just one piece of the overall safety analysis conducted for the proposed interchange alternatives. In addition to the safety analysis of the alternative junction types, CDOT developed crash estimates for each segment and intersection within the study area. The result was an estimate of annual crashes for the entire study area for Alternatives 1 and 2. The estimated safety performance of each alternative can then be considered with the operational performance, project costs, environmental impacts, and other factors to identify a balanced design and the most desirable alternative.
Case Study #2: Arizona
The following case study illustrates how the Expected Crash Frequency with CMF Adjustment method has been used to quantify the safety impacts during the development and analysis of alternatives. Information for the case study was provided by ADOT.
ADOT is performing predictive analyses following the procedures in the AASHTO Highway Safety Manual at the scoping and alternative selection stage of demonstration projects. They are working to develop a framework for integrating substantive safety considerations into the ADOT project planning and development process.
Project Description
ADOT identified potential safety improvements on a 24.6 mile section of Arizona State Route 264 (SR 264) and evaluated the potential safety impacts during the analysis phase of the development and analysis of the alternatives. SR 264 is a rural, two-lane road in northeastern Arizona and functionally classified as a minor arterial. Figure 2 identifies the general location and limits of the study section.
Findings
This case study presented an example of how the Expected Crash Frequency with CMF Adjustment method can be used to estimate the expected safety impacts of various design alternatives. ADOT used SPFs and CMFs from the Highway Safety Manual (HSM) in this analysis, supported by the Interactive Highway Safety Design Model (IHSDM) software. They also incorporated observed crash history, using the Empirical Bayes method, to estimate the expected crashes for various scenarios. The result was an estimate of total expected crashes for the entire study section over a 20-year analysis period. This allowed for a quantitative comparison of the safety performance for two design alternatives and the existing conditions. ADOT used the results of the crash analysis in a benefit-cost analysis to help select the most cost-effective alternative.
(The Michigan case study begins on Page 11 of the full report, after background information about the use of crash modification factors in the Roadway Safety Audit process.)
Background
Crash Modification Factors (CMFs) can be applied in the Roadway Safety Audit (RSA) process to quantify the safety effects of various treatments and justify the RSA team suggestions to the project owner and/or design team. The following case study illustrates how CMFs have been applied in the RSA process. It also identifies noteworthy practices and actual challenges encountered by agencies with respect to this process.
Project Description
The Michigan Department of Transportation (MDOT) conducted an Operational and Preliminary Design Stage RSA along the first horizontal curve on M-26 north of the village limits of South Range, in Houghton County. The RSA location is circled in Figure 2. This curve was chosen by MDOT on the basis of crash history.
The objectives of the RSA were to:
Review road safety at the curve.
Identify physical and operational issues that may affect road safety.
Review the proposed plan concept.
Develop and evaluate potential countermeasures to reduce the frequency and severity of collisions.
Findings
The RSA process is typically a qualitative evaluation of the safety performance of a given facility. The RSA report is generally the final deliverable of an RSA team, including a list of potential safety issues and associated countermeasures. It is then the responsibility of the project owner/design team to consider the suggestions identified by the RSA team and determine which countermeasures will be implemented and the relative timeframe for implementation. The application of CMFs not only helps an agency to compare the relative effectiveness of suggested countermeasures, but it also provides information to be used in a benefit-cost analysis. A benefit-cost analysis can be used to prioritize suggested improvements and may be required when applying for funding.
Summary from Crash Modification Factors in Practice: Quantifying Safety in the Roadway Safety Management Process
(The Virginia case study begins on Page 7 of the full report, after background information about the use of crash modification factors to quantify roadway safety.)
Background
In 2007, the Virginia Department of Transportation (VDOT) started a new program, Strategically Targeted Affordable Roadway Solutions (STARS), aimed at critical safety and congestion hot spots throughout the State. The primary goals of the STARS program are to identify roadway improvements on the interstate and primary systems that:
Are relatively low-cost.
Address existing mobility and safety problem areas.
Require minimal preliminary engineering and right-of-way.
Can be implemented quickly (24 months or less).
The STARS program allows VDOT to better incorporate operations and safety into the long-term planning process and involves the following four steps.
Study area selection.
Detailed safety and operational analysis.
Prioritization of recommendations.
Programming and implementation.
In this process, the study team identifies potential safety and operational issues in Step 2 along with a list of potential countermeasures. Crash Modification Factors (CMFs) are then applied in Step 3 to help justify and prioritize the suggestions. Specifically, CMFs are used to estimate the safety impacts associated with each countermeasure.
Findings
There are several potential benefits associated with the application of CMFs in the safety management process. Specifically, CMFs provide a means to quantify the safety impacts of decisions and help to raise awareness of safety. The application of CMFs also helps to prioritize potential treatments and provides decision-makers with the information needed to identify cost-effective strategies. VDOT indicated that the STARS program has helped to raise awareness of safety issues at both the State and local level, which has led to more safety-focused projects.
The goal of the STARS program is to identify where safety and congestion issues overlap on the State's roadways. As demonstrated in the case study, CMFs are used in the benefit-cost analysis to quantify the safety impact of the suggested countermeasures. The results of the benefit-cost analysis are beneficial in the prioritization of recommendations as well as the programming and implementation stage. VDOT indicated that STARS-based projects have addressed more crashes and typically involve lower impact treatments (less utility and right of way) that can be implemented more quickly than proposals submitted prior to the STARS program.
Using CMFs as part of the benefit-cost analysis is not only beneficial to prioritizing the suggested countermeasures for a particular site, but also helps in the management of a safety program. The STARS program actively utilizes Highway Safety Improvement Program (HSIP) funds for many of the hot spot locations throughout the State. The CMFs used in the benefit-cost analysis are instrumental in the application process for HSIP funding.
