Advanced Collision Avoidance Technologies (ACATs) range in effectiveness from 7 to 74 percent.

Electronic Stability Control, Forward Collision Avoidance Technology, Lane Departure Warning / Prevention found effective in reducing their targeted crash types.

Date Posted
12/19/2014
Identifier
2014-B00963
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Assessment of the Effectiveness of Advanced Collision Avoidance Technologies

Summary Information

The report examined several studies evaluating the effectiveness of advanced collision avoidance technologies (ACATs) for light-duty vehicles from the 2003 to 2013 time period. The technologies examined were: electronic stability control (ESC); forward collisions avoidance technology (FCAT) including forward collision warning (FCW), brake assist (BA), and autonomous emergency braking (AEB); and lane departure warning (LDW) and lane departure prevention (LDP).

Methodology



A range of methodologies were used, summarized as follows:

  • The effectiveness of ESC technology was assessed by comparing crash risk in crash types (rollover and single-vehicle crashes) where it would be expected to have an effect with crash risk in crash types where ESC should have no effect. System effectiveness was computed by comparing the ratio of ESC-relevant crashes to control crashes for ESC-equipped vehicles and for vehicles without ESC. A second methodology compared crash rates for ESC-quipped vehicles with non-ESC equipped vehicles in different categories of crashes.
  • To evaluated the safety impact of FCATs, the primary methodologies were either field operational tests (FOTs) or simulation. Crash reduction was estimated from the difference in the number of forward conflicts with and without the technology in a FOT or simulation environment.
  • The primary assessment tools for ACATs were simulations based on crash data analysis, and in some cases, FOTs in controlled experiments. In simulations, crash data were used to characterize the nature of the crashes due to lane departure. The difference between the simulated crash distribution with and without LDW or LDP provided an estimate of the effect of the system.

Findings



Findings from the report are summarized as follows:

  • ESC was substantially effective in reducing crashes, reducing overall crashes by 7 percent and injury crashes by 9 percent. ESC reduced single-vehicle crashes by 41 percent, and single vehicle fatal crashes by 56 percent. ESC was found to reduce single-vehicle rollovers by 75 percent and fatal single-vehicle rollovers by 87 percent..
  • Virtually all the studies examined indicated that FCATs are highly effective. Studies estimated the effectiveness of FCW alone as ranging from preventing 29 percent of severe injuries to preventing 38 percent of rear-end crashes.
  • Results from a small early field operational test estimated that the road departure system would reduce road departure crashes by 7 to 57 percent, with estimates from four different simulations putting the reduction of lane/road departure crashes at 6 to 34 percent..

As shown in the table below, the systems reviewed were estimated to be substantially effective in reducing their target crash types. The studies reviewed have a range of estimated reductions, and in some cases the differences were fairly substantial. However, even the lower-bound estimates are significant in most cases.

 

Measure

ESC

FCAT (FCW+BA+AEB)

LDW / LDP
All crashes

7-9%

   
All fatal crashes

25-33%

   
Fatal injuries in relevant crash types  

30-40%

7-29%

Serious injuries in relevant crash types  

27-50%

13-34%

Single vehicle crashes

34-41%

   
Rollover crashes

72-74%

   
Target crashes

See above

9.3-72%

6-34%



Most studies relied on simulation or limited field operational tests to evaluate effectiveness. The report concluded that, other than electronic stability control, available crash data cannot yet support evaluation of the actual crash experience of the technologies, because penetration rates are low and vehicles with the technologies are not directly identified in the data.

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