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Publication Number: FHWA-HRT-11-040
Date: November 2012

 

Crash Data Analyses for Vehicle-To-Infrastructure Communications for Safety Applications

Chapter 9. Conclusions

This report documents the annual national frequencies and costs of crashes that could be targeted for 12 of the currently identified V2I for safety application areas. These analyses also provide information on crash scenarios and the associated costs that are unaddressed by these 12 safety applications. These unaddressed crashes can be explored to identify other potential applications.

Table 22 summarizes the estimated annual crashes and associated costs that could be targeted by the 12 V2I for safety application areas. These application areas could potentially target a significant number of crashes and their associated crash costs (more than $200 billion annually). When combined, the costs would total more than $200 billion, and the overlap among some of the application areas is accounted for in the total. The lane departure application represents the greatest potential to improve safety with respect to crash frequency and the potential crash cost. This finding is expected because the targets for this application are several pre-crash scenarios with significant crashes resulting from vehicles leaving their lanes.

Table 22. Overview of annual target crashes and associated costs identified in NASS GES for currently identified application areas.

Application Area Estimated Annual Crashes Targeted Annual Cost of Crashes Targeted (millions of dollars)
Intersection applications Running red light 234,881 13,152
Running stop sign 44,424 2,034
Driver gap assist at signalized intersections 200,212 10,252
Driver gap assist at stop-controlled intersections 278,886 18,273
Speed applications Curve speed warning 168,993 29,080
Work zone warning for reduced speed 16,364 1,335
Spot treatment/weather conditions 211,304 13,019
Speed zone warning 360,695 28,500
Vulnerable road users applications Work zone alerts 86,611 4,563
Infrastructure pedestrian detection 17,812 3,333
At-grade rail crossing 1,314 653
Other applications Lane departure warning 1,236,647 145,347
Total (accounting for overlaps) 2,288,021 202,344

Some caution is necessary because these results represent all potential target crashes for each application area. Targeted crashes are those that could potentially be eliminated through the deployment of a specific V2I application or set of applications (assuming 100 percent effectiveness and 100 percent deployment). The actual number of crashes addressed depends on the effectiveness of the application and the extent to which it is deployed.

The 12 analyzed application areas have the potential to cover approximately 73 percent of the single-vehicle total crash costs and 47 percent of the multi-vehicle total crash costs (see table 1 and table 2). The remaining crashes are considered unaddressed crashes, which are crashes that would not be eliminated even if the analyzed V2I applications were 100 percent effective and fully deployed. Unaddressed crashes might be covered through the development of new application areas or by other V2I technologies. They account for $44.0 billion in single-vehicle crash costs and $92.8 billion in multi-vehicle crash costs.

The following currently identified V2I for safety application areas could not be explored due to small samples or limitations of the NASS GES data:

Other datasets and methods would be needed to identify the target populations for these application areas and estimate costs associated with these crash types.

Based on the percentage of crash costs targeted, current application areas appear to be well conceived in that they target major crash scenarios, particularly for single-vehicle crashes. In addition, a relatively large percentage of unaddressed crash costs are related to rear-end collisions. While V2I application areas could be conceived to target these scenarios, the Volpe report suggests V2V and AV as the primary applications areas for addressing rear-end crashes.(12)

More detailed crash data analysis is necessary to help target the deployment of V2I applications to identify the maximum benefit per dollar spent. For example, the benefits of the pre-crash scenario driver gap assist at signalized intersections would be expected to be greater at intersections with permissive left-turn phases and high numbers of potential conflicts (e.g., high volume of left-turn and opposing through vehicles).

This report identifies the magnitude, characteristics, and cost of crashes that would be targeted with currently proposed V2I safety application areas. It also identifies the magnitude, characteristics, and cost of the remaining crashes that are not targeted by a currently proposed V2I for safety application area (unaddressed crashes) to help identify potential new applications or modifications to proposed applications. The results indicate that the currently identified V2I application areas are well conceived and can potentially reduce crashes and crash costs. However, many crashes are not addressed in this report, and characteristics of unaddressed crashes are presented in this report provide a starting point for identifying either new applications or modifications to current applications

 

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