Skip to contentUnited States Department of Transportation - Federal Highway Administration FHWA Home
Research Home
REPORT
This report is an archived publication and may contain dated technical, contact, and link information
Publication Number: FHWA-HRT-11-040
Date: November 2012

 

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

Chapter 8. Unaddressed Crashes

Crashes identified in the NASS GES data that are not targeted by one or more of the current V2I application areas mentioned previously are considered unaddressed crashes. These crashes can be explored to identify other potential applications. This chapter provides information on these crashes.

8.1 Distribution by Pre-crash Scenarios

Table 9 and table 10 present the distribution and cost information of total and unaddressed crashes from NASS GES data sorted by pre-crash scenario for single-vehicle and multi-vehicle crashes, which are presented separately. The second row of table 9 indicates that for vehicle failure, unaddressed crashes represent 8 percent of total unaddressed crash costs, and 98 percent of the total crash cost for this scenario remains unaddressed. Pedestrian/no maneuver is the leading unaddressed single-vehicle pre-crash scenario, followed by cyclist/no maneuver and animal/no maneuver. Collectively, these three pre-crash scenarios represent 56 percent of the costs of unaddressed single-vehicle crashes. Unaddressed pedestrian, bicyclist, and animal pre-crash scenarios represent 67 percent of the unaddressed crash costs for single-vehicle crashes.

The distribution of unaddressed multi-vehicle crashes differed from the distribution of unaddressed single-vehicle crashes. Rear-end/LVS was the leading multi-vehicle pre-crash scenario followed by straight crossing path at non-signal and left turn across path/opposite direction at non-signal. Collectively, these three pre-crash scenarios represented 50 percent of the costs of unaddressed multi-vehicle crashes. The five rear-end pre-crash scenarios represented nearly 50 percent of the unaddressed multi-vehicle crashes and 44 percent of the unaddressed multi-vehicle crash costs. The Volpe report on frequency of target crashes suggests V2V and AV applications as the primary strategies for rear-end crashes.(9)

The annual cost of unaddressed crashes was $136.9 billion, which includes all single-vehicle and multi-vehicle crashes. The leading unaddressed pre-crash scenarios are discussed in detail in the following sections.

Table 9. Single-vehicle unaddressed crashes by pre-crash scenario.

Pre-Crash Scenario Total Crash Frequency Unaddressed Crash Frequency Unaddressed Cost (in millions of dollars) Percent of Unaddressed Total Cost Percent of Scenario Total Cost Unaddressed
1. No driver present 602 598 41 0 99
2. Vehicle failure 38,894 37,419 3,540 8 98
3. Control loss/vehicle action 77,173 24,145 1,446 3 23
4. Control loss/no vehicle action 457,714 0 0 0 0
5. Running red light 868 0 0 0 0
6. Running stop sign 3,586 0 0 0 0
7. Road edge departure/maneuver 85,141 56,215 1,718 4 51
8. Road edge departure/no maneuver 417,076 0 0 0 0
9. Road edge departure/backing 85,540 83,596 1,093 2 96
10. Animal/maneuver 17,844 17,735 172 0 99
11. Animal/no maneuver 295,063 291,390 3,936 9 95
12. Pedestrian/ maneuver 20,629 10,184 2,363 5 63
13. Pedestrian/ no maneuver 40,603 31,858 15,525 35 86
14. Cyclist/maneuver 21,022 20,629 2,222 5 99
15. Cyclist/ no maneuver 28,757 28,288 5,330 12 99
16. Backing into vehicle 371 371 4 0 100
18. Parking/same direction 163 147 10 0 83
19. Changing lanes/same direction 30,751 29,489 1,345 3 94
21. Opposite direction/maneuver 1,920 1,875 67 0 43
22. Opposite direction/no maneuver 25,593 0 0 0 0
23. Rear-end/striking maneuver 2,736 2,493 204 0 96
25. Rear-end/lead vehicle moving at lower constant speed (LVM) 2,131 1,746 201 0 92
26. Rear-end/LVD 7,771 6,828 674 2 92
27. Rear-end/LVS 8,057 7,498 284 1 90
31. SCP at non-signal 3,773 3,642 127 0 98
32. Turn at non-signal 7,572 7,193 315 1 94
33. Evasive maneuver/maneuver 3,624 3,486 148 0 97
34. Evasive maneuver/no maneuver 18,363 17,268 790 2 94
35. Rollover 6,126 0 0 0 0
36. Non-collision no impact 21,171 20,030 1,569 4 97
37. Object contacted/maneuver 68,220 66,574 930 2 92
38. Object contacted/no maneuver 78,808 0 0 0 0
Total 1,877,663 770,697 44,054 100 27

Note: Pre-crash scenarios for which there were no annual observed crashes were omitted from this table.

Table 10. Multi-vehicle unaddressed crashes by pre-crash scenario.

Pre-Crash Scenario Total Crash Frequency Unaddressed Crash Frequency Unaddressed Cost (in millions of dollars) Percent of Unaddressed Total Cost Percent of Scenario Total Cost Unaddressed
1. No driver present 0 0 0 0 N/A
2. Vehicle failure 11,881 11,613 1,210 1 98
3. Control loss/vehicle action 31,332 534 8 0 1
4. Control loss/no vehicle action 63,080 0 0 0 0
5. Running red light 234,013 0 0 0 0
6. Running stop sign 40,838 0 0 0 0
7. Road edge departure/maneuver 1,479 1,394 162 0 97
8. Road edge departure/no maneuver 4,299 0 0 0 0
9. Road edge departure/backing 0 0 0 0 N/A
10. Animal/maneuver 404 404 8 0 100
11. Animal/no maneuver 6,065 5,645 344 0 93
12. Pedestrian/maneuver 646 641 22 0 98
13. Pedestrian/no maneuver 2,861 2,406 862 1 94
14. Cyclist/ maneuver 155 89 7 0 73
15. Cyclist/ no maneuver 500 438 96 0 99
16. Backing into vehicle 130,865 126,724 1,315 1 97
17. Turning/same direction 199,311 191,328 5,565 6 96
18. Parking/same direction 38,088 37,017 928 1 98
19. Changing lanes/same direction 309,933 295,994 6,189 7 96
20. Drifting/same lane 110,959 106,690 2,932 3 93
21. Opposite direction/maneuver 8,384 7,961 1,923 2 84
22. Opposite direction/no maneuver 97,565 0 0 0 0
23. Rear-end/striking maneuver 80,087 74,510 1,872 2 93
24. Rear-end/lead vehicle accelerating (LVA) 22,049 19,658 619 1 89
25. Rear-end/LVM 199,714 180,858 8,445 9 93
26. Rear-end/LVD 386,480 346,492 8,911 10 91
27. Rear-end/LVS 930,045 819,513 21,094 23 88
28. LTAP/OD at signal 200,212 0 0 0 0
29. Turn right at signal 30,980 30,251 957 1 97
30. Left turn across path/opposite direction at non-signal 182,574 178,663 11,260 12 95
31. SCP at non-signal 641,880 360,234 14,037 15 43
32. Turn at non-signal 38,788 29,229 570 1 81
33. Evasive maneuver/maneuver 8,936 8,317 269 0 93
34. Evasive maneuver/no maneuver 28,408 26,508 1,504 2 96
35. Rollover 450 443 409 0 100
36. Non-collision no impact 15,318 14,962 262 0 96
37. Object contacted/maneuver 595 507 29 0 92
38. Object contacted/no maneuver 9,220 8,755 369 0 96
39. Hit and run 3,551 3,547 64 0 91
40. Other-rear-end 1,516 1,427 19 0 98
41. Other-sideswipe 1,875 1,860 31 0 89
43. Other-turn across path 836 836 4 0 100
44. Other-turn into path 1,417 1,417 21 0 100
46. Other 22,347 22,016 527 1 97
Total 4,099,936 2,918,881 92,846 100 53

N/A = Not applicable.

Note: Pre-crash scenarios for which there were no annual observed crashes were omitted from this table.

8.2 Characteristics of Leading Unaddressed Crashes by Pre-crash Scenario

8.2.1 Single-Vehicle Pedestrian Crashes

A total of 40 percent of unaddressed costs for single-vehicle crashes were represented by two pedestrian pre-crash scenarios, pedestrian/maneuver and pedestrian/no maneuver, with the latter being the more prevalent of the two. The estimated total annual cost of unaddressed single-vehicle pedestrian crashes was more than $17.8 billion. As stated in the Volpe report, these two crash scenarios are primarily targeted by AV applications, with the V2I applications only addressing crashes that occur at crosswalks.(9)

The locations of these unaddressed pedestrian crashes are presented in table 11. There were no unaddressed pedestrian crashes at signalized intersections because those crashes are targeted by one of the currently identified applications and were previously discussed in this report. Intersections represented 35 percent of unaddressed single-vehicle pedestrian crashes, while the majority (58 percent) were non-junction crashes. The remaining crashes occurred at driveways/alleys (6 percent) and other locations. Additionally, 10 percent of the unaddressed pedestrian crashes occurred at stop-controlled intersections, which could potentially be targeted through the extension of the driver gap assist at stop-controlled intersections application as discussed in section 4.4 of this report.

Notably, the segment crashes represented the more severe crashes. Although segments represented 58 percent of the crashes, they represented 97 percent of the fatalities.

Table 11. Distribution of crash location for annual national (weighted) unaddressed pedestrian crashes.

Location of Crash Crashes Percent
Intersections Signalized 0 0
Stop-controlled 4,346 10
Other Intersections 10,707 25 
Segments Tangents 23,331 55
Curves 1,092 3 
Driveways Tangents 2,520 6
Curves 47 0 
Total   42,043 100

In total, 77 percent of these crashes occurred in urban areas. The majority of crashes also occurred on moderate speed roadways, with two-thirds of those crashes occurring on roadways with posted speeds limits of 25-35 mi/h. Crashes mainly occurred on two-lane roadways (41 percent).

8.2.2 Single-Vehicle Bicycle Crashes

In total, 17 percent of the total unaddressed costs for single-vehicle crashes were represented by two bicycle pre-crash scenarios, cyclist/maneuver and cyclist/no maneuver, with the latter being the more prevalent of the two. The estimated total annual cost of unaddressed single-vehicle bicycle crashes was more than $7.5 billion. The primary strategies proposed for addressing cyclist crashes are AV applications, as reported in the Volpe study.(9)

Table 12 presents the number and percentage of crashes based on location of unaddressed single-vehicle bicycle crashes. Intersection-related crashes represented 64 percent of unaddressed single-vehicle bicycle crashes, 21 percent of crashes were non-junction crashes, and 15 percent occurred at driveways/alleys.

Table 12. Distribution of crash location for annual national (weighted) unaddressed bicycle crashes.

Location of Crash Crashes Percent
Intersections Signalized 12,520 26
Stop-controlled 10,870 22
Other Intersections 7,810 16
Segments Tangents 9,429 19
Curves 886 2
Driveways Tangents 7,221 15
Curves 181 0
Total 48,917 100

Over 70 percent of the unaddressed bicycle crashes occurred in urban areas. The majority of crashes also occurred on moderate-speed roadways, with 70 percent of the crashes occurring on roadways with posted speeds limits of 25-35 mi/h. Additionally, 40 percent of the crashes occurred on two-lane roadways.

8.2.3 Single-Vehicle Animal Crashes

A total of 9 percent of the total unaddressed single-vehicle crashes were represented by two animal pre-crash scenarios, animal/maneuver and animal/no maneuver, with the latter being the more prevalent of the two. While 91 percent of the unaddressed animal crashes resulted in no injury, the estimated total annual cost of unaddressed animal crashes was more than $4.1 billion due to the large frequency of these crashes. Similar to cyclist crashes, AV applications are proposed as strategies for targeting animal crashes.(9)

Over half of the unaddressed animal crashes (57 percent) occurred in rural areas, while the remaining 43 percent occurred in urban areas, indicating that animal crashes do not occur in just one area type (see table 13). The distribution of animal crashes by location (tangent and curve) and area type indicated that the crashes predominately occurred on tangent sections for both urban and rural locations (88 and 90 percent, respectively).

Table 13. Distribution of area type for annual national (weighted) unaddressed animal crashes.

Area Type Crashes Percent
Urban 133,695 43
Rural 175,430 57
Total 309,125 100

The distribution of vehicle type for single-vehicle animal crashes indicated that light vehicles were involved in 95 percent of the crashes. Other vehicles accounted for 2 percent of the crashes. Each of the remaining vehicle types accounted for 1 percent or less of the total animal crashes.

8.2.4 Rear-End Crashes

A total of 44 percent of the total unaddressed multi-vehicle crashes were represented by five multi-vehicle rear-end pre-crash scenarios: rear-end/striking maneuver, rear-end/LVA, rear-end/ LVM, rear-end/LVD, and rear-end/LVS. The latter pre-crash scenario was the most prevalent of the five. The estimated total annual cost of unaddressed rear-end crashes was more than $40.9 billion. As previously mentioned, the majority of rear-end crashes are addressed by V2V and AV applications, which was a main cause for the high number of unaddressed read-end crashes in the Volpe report.(9) However, there were a substantial number of rear-end crashes targeted by the speed zone, work zone, and speed work zone V2I applications.

Table 14 presents the distribution of location for unaddressed crashes with urban and rural locations combined. Approximately half of the crashes occurred at intersection locations, and half occurred on roadway segments. The distribution by area type, shown in table 15, indicates that 76 percent of the crashes occurred in urban areas.

Table 14. Distribution of crash location for annual national (weighted) unaddressed rear-end crashes.

Location of Crash Crashes Percent
Intersections Signalized 442,037 31
Stop-controlled 50,377 3
Other intersections 199,728 14 
Segments Tangents 679,041 47
Curves 69,848 5 
Total 1,441,030 100

Table 15. Distribution of area type for annual national (weighted) unaddressed rear-end crashes.

Area Type Crashes Percent
Urban 1,094,013 76
Rural 346,936 24
Unknown 81 0
Total 1,441,030 100

The distribution of vehicle type for multi-vehicle rear-end crashes indicated that crashes involving only light vehicles represented 93 percent of the crashes. Trucks, including single-unit and combination-unit vehicles, constituted 4 percent of rear-end crashes.

8.2.5 Straight Crossing Path Crashes at Non-Signals

A total of 15 percent of the total unaddressed multi-vehicle crashes were represented by the pre-crash scenario straight crossing path crashes at non-signals. The estimated total annual cost of these target crashes was more than $14 billion.

Table 16 presents the distribution of locations of unaddressed crashes. Notably, 53 percent of unaddressed straight crossing path at non-signal crashes occurred at driveways/alleys. The Volpe report proposes V2I applications for straight crossing path crashes at intersections and V2V applications for the straight crossing path crashes at non-intersections such as driveways.(9) Table 17 shows the distribution of these crashes by area type.

Table 16. Distribution of crash location for annual national (weighted) straight crossing path crashes at non-signals.

Location of Crash Crashes Percent
Intersections Flashing signals 13,901 4
Stop-controlled 61,258 17
Other intersections 80,276 22 
Segments Tangents 10,162 3
Curves 1,731 0 
Driveways Tangents 184,152 51
Curves 8,754 2 
Total 360,234 100

Table 17. Distribution of area type for annual national (weighted) straight crossing path crashes at non-signals.

Area Type Crashes Percent
Urban 265,686 74
Rural 94,548 26
Total 360,234 100

The distribution of vehicle type for multi-vehicle, straight crossing path crashes at non-signals indicated that crashes only involving light vehicles represented 91 percent of crashes. Trucks, including single-unit and combination-unit vehicles, were involved in 4 percent of the crashes.

8.2.6 Left Turn Across Path/Opposite Direction Crashes at Non-Signals

The pre-crash scenario left turn across path/opposite direction at non-signals represented a total of 12 percent of the total unaddressed multi-vehicle crashes. The estimated total annual cost of these target crashes was more than $11.2 billion. The Volpe report proposes V2I applications only address intersection crashes for this pre-crash scenario, while V2V applications address all remaining crashes.(9)

Table 18 presents the distribution of locations of unaddressed crashes. While the majority (60 percent) of the unaddressed left turn across path/opposite direction at non-signal crashes occurred at intersection or intersection related locations, 37 percent occurred at driveways/alleys.

Table 18. Distribution of crash location for annual national (weighted) unaddressed left turn across path/opposite direction crashes at non-signals.

Location of Crash Crashes Percent
Intersections Flashing signals 6,200 3
Stop-controlled 16,554 9
Other intersections 86,236 48 
Segments Tangents 3,932 2
Curves 154 0 
Driveways Tangents 62,171 35
Curves 3,415 2 
Total 178,663 100

A total of 18 percent of the crashes occurred on non-level roadways (i.e., on a grade, hillcrest, or sag). Over two-thirds (71 percent) of these unaddressed crashes occurred in urban areas, and two-thirds of the crashes occurred on roadways with a speed limit between 35 and 45 mi/h. The distribution of vehicle type for unaddressed multi-vehicle left turn across path/opposite direction crashes at non-signals indicated that crashes only involving light vehicles represented 96 percent of the crashes. Trucks, including single- and combination-unit vehicles, were involved in less than 3 percent of the crashes.

8.3 Characteristics of Unaddressed Crashes by Vehicle, Area, and Location Type

8.3.1 Vehicle Type

The distribution of unaddressed single-vehicle and multi-vehicle crashes by vehicle type is presented in table 19. For single-vehicle crashes, single-unit and combination-unit trucks appear to be overrepresented, accounting for 8 percent of the vehicles. Other vehicles also are overrepresented when compared to multi-vehicle crashes, representing another 6 percent of the unaddressed crashes.

Table 19. Distribution of vehicle type for unaddressed crashes.

Vehicle Type Single-Vehicle Crashes Multi-Vehicle Crashes Total
Number of Vehicles Involved Percent Number of Vehicles Involved Percent Number of Vehicles Involved Percent
Light vehicles 666,118 86 5,430,129 93 6,096,247 92
Transit vehicles 2,334 0 24,471 0 26,805 0
Special vehicles 3,466 0 15,965 0 19,431 0
Single-unit trucks 35,057 5 112,382 2 147,439 2
Combination-unit trucks 20,101 3 106,979 2 127,080 2
Other vehicles 44,457 6 100,619 2 145,076 2
Not reported 0 0 47,216 1 47,216 1
Total 771,533 100 5,837,761 100 6,609,294 100

8.3.2 Area Type

Table 20 presents the distribution of unaddressed crashes by area type for single-vehicle and multi-vehicle crashes. More than 70 percent of the unaddressed crashes were in urban areas. Urban locations represented a greater proportion of the unaddressed crashes for multi-vehicle crashes than for single-vehicle crashes.

Table 20. Distribution of area type for unaddressed crashes.

Area Type Single-Vehicle Multi-Vehicle Total
Crashes Percent Crashes Percent Crashes Percent
Urban 454,274 59 2,171,556 74 2,625,829 71
Rural 317,164 41 747,152 26 1,064,316 29
Unknown 95 0 173 0 268 0
Total 771,533 100 2,918,881 100 3,690,413 100

8.3.3 Location Type

Table 21 presents the distribution of unaddressed crashes by intersection and segment locations. For both single-vehicle and multi-vehicle crashes, the majority of the unaddressed crashes were on tangent segments. This was expected because many of the current applications target intersections and curved segments. Specifically, 75 percent of single-vehicle crashes compared to 51 percent of multi-vehicle crashes occurred on tangents. Furthermore, the difference in percentage between single-vehicle and multi-vehicle crashes for crashes at intersections and segments was expected because multi-vehicle crashes are generally more prevalent at intersections. Additionally, 21 percent of the unaddressed multi-vehicle crashes were at signalized intersections. Signalized intersections could be a target for new applications or extensions to existing application areas.

Table 21. Distribution of crash location for unaddressed crashes.

Location of Crash Single-Vehicle Multi-Vehicle Total
Crashes Percent Crashes Percent Crashes Percent
Intersections Signalized 31,800 4 613,532 21 645,332 17
Stop-controlled 27,835 4 163,404 6 191,239 5
Other intersections 73,829 10 512,332 18 586,161 16
Segments Tangents 575,672 75 1,500,622 51 2,076,294 56
Curves 62,397 8 128,990 4 191,387 5
Total 771,533 100 2,918,881 100 3,690,413 100

 

ResearchFHWA
FHWA
United States Department of Transportation - Federal Highway Administration