Quality data are the foundation for making important decisions regarding the design, operation, and safety of roadways.  By incorporating roadway and traffic data into safety analysis procedures, States can better identify safety problems and prescribe solutions to support their Highway Safety Improvement Programs (HSIP) and implement their Strategic Highway Safety Plans (SHSP).  Furthermore, a new generation of safety analysis tools and methods are being developed to help identify safety issues and provide recommendations for improvements.  These safety analysis tools, such as the Highway Safety Manual (HSM) and related SafetyAnalyst and Interactive Highway Safety Design Model (IHSDM) software, all require quality roadway, traffic, and crash data to achieve the most accurate results.  Using roadway and traffic data together with crash data can help agencies to make decisions that are fiscally responsible and to improve the safety of the roadways for all users.

While HSIP guidance provides information on how safety data should be used, there is no additional detail on the specific data elements that State and local agencies should be collecting, maintaining, and using to support their HSIPs and SHSPs.  In response to this gap, the Federal Highway Administration (FHWA) held a series of information gathering sessions in 2009 and 2010 and convened a Technical Working Group (TWG) from 2010 through 2011 to determine a minimum set of roadway and traffic data elements that States should be collecting; what data States are capable of collecting given the current economic environment; and the importance of using roadway and traffic data to support the States’ HSIPs.

States should have a common statewide location referencing system, such as a geographic information system (GIS) or a linear referencing system, on all public roads.  These systems will enable States to identify high crash locations on all their public roads.  As States expand their inventories, these common statewide systems will enable States to link these locations with additional data systems, such as roadway and traffic data.

States should also be collecting a set of minimum roadway and traffic data elements that are fundamental to support their HSIPs. This set of elements is herein referred to as the Fundamental Data Elements for HSIP (FDE/HSIP).    

The FDE/HSIP are based on the minimum required elements needed to use enhanced safety analysis tools and methods, including the HSM and related software SafetyAnalyst.  They are a subset of the Model Inventory Roadway Elements (MIRE) and duplicate many of the Highway Performance Monitoring System (HPMS) full extent elements that States are already required to collect (1).  These FDE/HSIP elements include segment, intersection, and ramp data elements and were determined to be the basic set of data elements an agency would need to conduct enhanced safety analysis to support States’ HSIPs.

While the FDE/HSIP were selected in part based on the basic data requirements of existing tools such as such as the HSM and related SafetyAnalyst, they are not exclusive to these tools. The FHWA recognizes that many States are developing analysis tools in-house that will help to support their HSIPs.  The FDE/HSIP are a basic set of elements an agency would need to conduct effective, enhanced safety analysis independent of the specific analysis tools used or methods applied.  All States should be moving towards using analysis tools and having the FDE/HSIP available to utilize these tools, regardless of whether they are the tools developed through Federal efforts or they are developed in-house.

The objective of this effort was to conduct a market analysis of the potential cost to States in developing a statewide location referencing system and collecting the FDE/HSIP on all public roadways.  The primary theory is that collecting additional roadway and traffic data and integrating those data into the safety analysis process will improve an agency’s ability to locate problem areas and apply appropriate countermeasures, hence improving safety.  This effort also investigated potential methodologies that could be applied to estimate the benefits in terms of safety of collecting this additional roadway information.

A literature review was conducted to identify resources to help develop a methodology for analysis of the cost and benefits of collecting roadway data to improve highway safety.  The literature review showed there were no established methodologies to estimate the benefit of collecting roadway data elements for safety.  An alternate approach was developed to conduct the market analysis.  The costs for data collection were gathered from several vendors and one State department of transportation (DOT) that had been investigating a similar effort.  The numbers of fatalities and injuries that would need to be reduced in order to exceed the costs (for a 1:1 and 2:1 ratio) were estimated to determine the benefits.  That is, this analysis identified the benefit required to obtain cost effectiveness.

The cost estimations developed for this analysis reflect the additional costs that States would incur based on what is not already being collected through HPMS or not already being collected through other efforts.  At the time of this analysis, the FHWA did not know the extent of data collection practices for all States beyond HPMS requirements.  In order to accommodate a range of data collection practices among the States, the methodology for the analysis was conservatively based on the assumption that all data collection beyond HPMS requirements would be new collection.  Therefore, this analysis of the additional cost to States is most likely greater than the actual cost that would be incurred.  Individual cost estimates would vary by the circumstances in each State.

Costs

A summary of the additional costs identified includes the following three sets of data elements:

• A common relational location referencing system on all public roads.
  • Additional costs would only be incurred on all non-Federal-aid roadways, since HPMS currently requires this for Federal-aid highways.
• The 22 FDE/HSIP that are not required under HPMS on all public roads.
  • Additional costs would only be incurred on Federal-aid roadways since 16 of the 37 total FDE/HSIP are already required for HPMS on Federal-aid highways.
• The complete 38 FDE/HSIP on all public roads.
  • Additional costs would be incurred on all non-Federal-aid highways, since HPMS does not require data collection of these elements on non-Federal-aid roadways.

The costs were collected from a variety of vendors and were broken down into a per-mile basis for segments, per intersection, and per ramp.  The summary of data collection costs is shown in Table 1.

Table 1. Summary of Average Data Collection Costs in Addition to HPMS Requirements
(2010 U.S. Dollars)

Benefits

There are no established methodologies for estimating the safety benefits of collecting roadway data elements.  It was not feasible at the time this analysis was conducted to develop a direct estimate of the safety benefits of collecting roadway inventory data.  In lieu of a traditional cost-benefit estimate, a “cost effectiveness” approach was taken. 

For the purposes of this analysis, work was conducted to determine what safety benefits would need to be realized from data collection in order to exceed the costs of collection. The needed benefits were calculated by developing an estimate of the number of fatalities and injuries that would need to be reduced in order to exceed a 1:1 ratio and a 2:1 ratio of benefits to costs. These estimates were developed for two scenarios:

Scenario 1:

• Develop a common statewide relational location referencing system on all public roads that is linkable with crash data (i.e., geographic information system, linear referencing system, etc).
  • This would require developing a referencing system on all non-Federal-aid roadways, since HPMS currently requires this for Federal-aid highways.
• Collect the FDE/HSIP on all Federal-aid highways.
  • This would require collecting the 22 FDE/HSIP that are not required under HPMS on roads, since 16 of the 37 total FDE/HSIP are already required for HPMS on Federal-aid highways.

Scenario 2:

• Develop a common statewide relational location referencing system on all public roads that is linkable with crash data (i.e., GIS, linear referencing system, etc).
  • This would require developing a referencing system on all non-Federal-aid roadways, since HPMS currently requires this for Federal-aid highways.
• Collect the FDE/HSIP on all Federal-aid highways.
  • This would require collecting the 22 FDE/HSIP that are not required under HPMS on roads, since 16 of the 37 total FDE/HSIP are already required for HPMS on Federal-aid highways.
• Collect the FDE/HSIP on all non-Federal-aid roads.
  • This would require collecting all 38 FDE/HSIP along all non-Federal-aid highways, since HPMS does not require data collection of these elements on non-Federal-aid roadways.

For both Scenarios, the first two initiatives would involve developing a statewide relational location referencing system on all public roads, and collecting the FDE/HSIP on all Federal-aid highways.  Scenario 2 adds a third initiative of collecting the FDE/HSIP in all non-Federal-aid roads. 

The analysis period for this effort was established to be 2012 – 2031.  The costs were aggregated out to the State level, and then the estimated needed reductions in fatalities and injuries were determined based on the costs for each scenario. Both the costs and benefits were estimated across the analysis period and discounted to reflect 2010 U.S. dollars. The results of the analysis are shown in Table 2.  

For Scenario 1, the average annual cost of data collection for an average State (based on HPMS mileage) is $6.3 million for initial collection and $3.4 million for maintenance over the analysis period of 2012 – 2031 (in 2010 U.S. dollars).  Using a base of $6,339,701 as the comprehensive cost of a fatality and $516,947 as the comprehensive cost for an injury, a reduction of  0.6 fatalities and 41.0 injuries is required to achieve a greater than 1:1 benefit to cost ratio (2).  For Scenario 2, 2.5 fatalities and 163.7 injuries are needed to achieve greater than a 1:1 benefit.  Scenario 2 includes collecting the FDE/HSIP on both Federal-aid and non-Federal-aid roads.

Table 2. Summary of Analysis for Average State
Analysis Period 2012 – 2031
Average Annual Costs and Needed Benefits
(Millions of 2010 U.S. Dollars)

Note - Costs are accumulated throughout the entire analysis period; benefits are realized after the data collection is complete.

Future Research

This effort was a preliminary attempt to quantify the costs and benefits of collecting roadway and traffic data for safety.  The primary theory driving the analysis is that collecting additional roadway and traffic data and integrating those data into the safety analysis process will improve an agency’s ability to locate problem areas and apply appropriate countermeasures, hence improving safety.  Based on the work conducted for this effort, including a thorough literature review, it was determined that there are no established methodologies for quantifying the benefits of investing in safety data improvements.  Additional research needs to be conducted to build upon the analysis provided in this report to work towards filling that knowledge gap by developing guidance on the methodologies that can be applied to determine the benefits of investing in data systems and processes for achieving a data-driven safety program.  Developing such methodologies would be the crucial next step to help the FHWA Office of Safety achieve its goal to reduce highway fatalities by providing decision makers the tools they need to make informed decisions through an evidenced-based approach to safety implementation.