Airbag deployment thresholds can be a useful metric
of collision severity in accident reconstruc... more Airbag deployment thresholds can be a useful metric
of collision severity in accident reconstruction applications.
The National Automotive Sampling System
(NASS) has provided a publicly-available database of realworld
motor vehicle collisions, including more than 10,000
event data recorder (EDR) reports retrieved from airbag
control modules. These reports typically indicate the airbag
deployment status and the corresponding Delta-V of each
recorded event. A prior study analyzing crash data in the
NASS database demonstrated the airbag deployment threshold
varies between vehicle manufacturers and over time. However,
the analysis was limited to Ford and GM vehicles due to insufficient
data. This paper expands on the prior study of frontal
airbag deployment thresholds by analyzing newer years of
NASS EDR data (4,000 additional reports). We found that the
Delta-V threshold for a 50% probability of deployment event
is higher for Toyota than for GM and Ford vehicles. Moreover,
SUVs and pickup trucks had higher deployment thresholds
than sedans. An increase in Delta-V thresholds was observed
for more recent vehicle model years. A higher Delta-V is
required for frontal airbag deployment in underride collisions,
in which a sedan contacted a vehicle with higher ground clearance
(SUV, pickup truck, or van), compared to collisions with
direct bumper-bumper engagement. Based on the findings,
we developed a logistic regression model that predicts the
probability of frontal airbag deployment with a known change
in velocity (ΔV = 0 to 45 mph), vehicle manufacturer (GM,
Toyota, Ford), vehicle type (sedan, SUV, pickup truck), model
year (1994-2001, 2002-2016), and impact configuration
(underride, bumper-bumper) with 82% accuracy. This study
provides information about airbag deployment behavior
beyond what is reported in owner’s manuals and National
Highway Traffic Safety Administration (NHTSA) guidelines.
The repeatability and accuracy of front and rear speed changes reported by Toyota's Airbag Contro... more The repeatability and accuracy of front and rear speed changes reported by Toyota's Airbag Control Modules (ACMs) have been previously characterized for low-severity collisions simulated on a linear sled. The goals of the present study are (i) to determine the accuracy and repeatability of Toyota ACMs in mid-severity crashes, and (ii) to validate the assumption that ACMs function similarly for idealized sled pulses and full-scale vehicle-to-barrier and vehicle-to-vehicle crashes. We exposed three Toyota Corollas to a series of full-scale aligned frontal and rear-end crash tests with speed changes (ΔV) of 4 to 12 km/h. We then characterized the response of another 16 isolated Toyota ACMs from three vehicle models (Corolla, Prius and Camry) and 3 generations (Gen 1, 2 and 3) using idealized sled pulses and replicated vehicle-to-vehicle and vehicle-to-barrier pulses in both frontal and rear-end crashes (ΔV = 9 to 17 km/h). The ACM-reported speed changes were compared to reference speed changes calculated by integrating an accelerometer signal. The pooled data for reference speed change were then linearly regressed against the following predictors: ACM-reported speed change, peak acceleration, vehicle type, collision type and ACM generation. We found that all of the independent variables had a significant effect in at least one of the models we considered, although ACM-reported speed change and ACM generation had the largest effects on the outcome. We found significant differences between the full-scale collisions and the sled pulses for frontal impacts, but these differences were small (<0.2 km/h) compared to the other variables. This study furthers our understanding of how Toyota ACMs behave in low and mid-severity collisions.
The objective of this study was to assess the accuracy of using high-speed frontal barrier crash ... more The objective of this study was to assess the accuracy of using high-speed frontal barrier crash tests to predict the impact speed, i.e. equivalent barrier speed (EBS), of a lower-speed frontal barrier crash. Force-displacement (F-D) curves were produced by synchronizing the load cell barrier (LCB) data with the accelerometer data. Our analysis revealed that the F-D curves, including the rebound phase, for the same vehicle model at the same impact speed were generally similar. The test vehicle crush at the time of barrier separation, determined from the F-D curves, was on average 17±16% (N = 150) greater than the reported maximum hand-measured residual crush to the bumper cover. The EBS calculated from the F-D curves was on average 4±4% (N=158) greater than the reported EBS, indicating that using F-D curves derived from LCB data is a reliable method for calculating vehicle approach energy in a crash test. Our method of using F-D curves from high-speed tests to predict the EBS of a lower-speed barrier crash overestimated the EBS of actual lower-speed tests by an average of 21±9% (N = 129). Further work in developing and refining our method is needed to improve the accuracy of predicting a lower-speed EBS.
The accuracy of the speed change reported by Generation 1 Toyota Corolla Event Data Recorders (ED... more The accuracy of the speed change reported by Generation 1 Toyota Corolla Event Data Recorders (EDR) in low-speed front and rear-end collisions has previously been studied. It was found that the EDRs underestimated speed change in frontal collisions and overestimated speed change in rear-end collisions. The source of the uncertainty was modeled using a threshold acceleration and bias model. This study compares the response of Generation 1, 2 and 3 Toyota EDRs from Toyota Corolla, Camry and Prius models. 19 Toyota airbag control modules (ACMs) were mounted on a linear sled. The ACMs underwent a series of frontal and rear-end haversine crash pulses of varying severity, duration and peak acceleration. The accuracy and trigger thresholds of the different models and generations of EDRs were compared. There were different accuracy trends found between the early Generation 1 and the more modern Generation 2 and 3 EDRs. There were also differences found in the threshold and trigger characteristics of the Generation 3 EDRs. This study extends the understanding of how Toyota EDRs respond in low speed collisions with various collision parameters.
Airbag deployment thresholds can be a useful metric
of collision severity in accident reconstruc... more Airbag deployment thresholds can be a useful metric
of collision severity in accident reconstruction applications.
The National Automotive Sampling System
(NASS) has provided a publicly-available database of realworld
motor vehicle collisions, including more than 10,000
event data recorder (EDR) reports retrieved from airbag
control modules. These reports typically indicate the airbag
deployment status and the corresponding Delta-V of each
recorded event. A prior study analyzing crash data in the
NASS database demonstrated the airbag deployment threshold
varies between vehicle manufacturers and over time. However,
the analysis was limited to Ford and GM vehicles due to insufficient
data. This paper expands on the prior study of frontal
airbag deployment thresholds by analyzing newer years of
NASS EDR data (4,000 additional reports). We found that the
Delta-V threshold for a 50% probability of deployment event
is higher for Toyota than for GM and Ford vehicles. Moreover,
SUVs and pickup trucks had higher deployment thresholds
than sedans. An increase in Delta-V thresholds was observed
for more recent vehicle model years. A higher Delta-V is
required for frontal airbag deployment in underride collisions,
in which a sedan contacted a vehicle with higher ground clearance
(SUV, pickup truck, or van), compared to collisions with
direct bumper-bumper engagement. Based on the findings,
we developed a logistic regression model that predicts the
probability of frontal airbag deployment with a known change
in velocity (ΔV = 0 to 45 mph), vehicle manufacturer (GM,
Toyota, Ford), vehicle type (sedan, SUV, pickup truck), model
year (1994-2001, 2002-2016), and impact configuration
(underride, bumper-bumper) with 82% accuracy. This study
provides information about airbag deployment behavior
beyond what is reported in owner’s manuals and National
Highway Traffic Safety Administration (NHTSA) guidelines.
The repeatability and accuracy of front and rear speed changes reported by Toyota's Airbag Contro... more The repeatability and accuracy of front and rear speed changes reported by Toyota's Airbag Control Modules (ACMs) have been previously characterized for low-severity collisions simulated on a linear sled. The goals of the present study are (i) to determine the accuracy and repeatability of Toyota ACMs in mid-severity crashes, and (ii) to validate the assumption that ACMs function similarly for idealized sled pulses and full-scale vehicle-to-barrier and vehicle-to-vehicle crashes. We exposed three Toyota Corollas to a series of full-scale aligned frontal and rear-end crash tests with speed changes (ΔV) of 4 to 12 km/h. We then characterized the response of another 16 isolated Toyota ACMs from three vehicle models (Corolla, Prius and Camry) and 3 generations (Gen 1, 2 and 3) using idealized sled pulses and replicated vehicle-to-vehicle and vehicle-to-barrier pulses in both frontal and rear-end crashes (ΔV = 9 to 17 km/h). The ACM-reported speed changes were compared to reference speed changes calculated by integrating an accelerometer signal. The pooled data for reference speed change were then linearly regressed against the following predictors: ACM-reported speed change, peak acceleration, vehicle type, collision type and ACM generation. We found that all of the independent variables had a significant effect in at least one of the models we considered, although ACM-reported speed change and ACM generation had the largest effects on the outcome. We found significant differences between the full-scale collisions and the sled pulses for frontal impacts, but these differences were small (<0.2 km/h) compared to the other variables. This study furthers our understanding of how Toyota ACMs behave in low and mid-severity collisions.
The objective of this study was to assess the accuracy of using high-speed frontal barrier crash ... more The objective of this study was to assess the accuracy of using high-speed frontal barrier crash tests to predict the impact speed, i.e. equivalent barrier speed (EBS), of a lower-speed frontal barrier crash. Force-displacement (F-D) curves were produced by synchronizing the load cell barrier (LCB) data with the accelerometer data. Our analysis revealed that the F-D curves, including the rebound phase, for the same vehicle model at the same impact speed were generally similar. The test vehicle crush at the time of barrier separation, determined from the F-D curves, was on average 17±16% (N = 150) greater than the reported maximum hand-measured residual crush to the bumper cover. The EBS calculated from the F-D curves was on average 4±4% (N=158) greater than the reported EBS, indicating that using F-D curves derived from LCB data is a reliable method for calculating vehicle approach energy in a crash test. Our method of using F-D curves from high-speed tests to predict the EBS of a lower-speed barrier crash overestimated the EBS of actual lower-speed tests by an average of 21±9% (N = 129). Further work in developing and refining our method is needed to improve the accuracy of predicting a lower-speed EBS.
The accuracy of the speed change reported by Generation 1 Toyota Corolla Event Data Recorders (ED... more The accuracy of the speed change reported by Generation 1 Toyota Corolla Event Data Recorders (EDR) in low-speed front and rear-end collisions has previously been studied. It was found that the EDRs underestimated speed change in frontal collisions and overestimated speed change in rear-end collisions. The source of the uncertainty was modeled using a threshold acceleration and bias model. This study compares the response of Generation 1, 2 and 3 Toyota EDRs from Toyota Corolla, Camry and Prius models. 19 Toyota airbag control modules (ACMs) were mounted on a linear sled. The ACMs underwent a series of frontal and rear-end haversine crash pulses of varying severity, duration and peak acceleration. The accuracy and trigger thresholds of the different models and generations of EDRs were compared. There were different accuracy trends found between the early Generation 1 and the more modern Generation 2 and 3 EDRs. There were also differences found in the threshold and trigger characteristics of the Generation 3 EDRs. This study extends the understanding of how Toyota EDRs respond in low speed collisions with various collision parameters.
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of collision severity in accident reconstruction applications.
The National Automotive Sampling System
(NASS) has provided a publicly-available database of realworld
motor vehicle collisions, including more than 10,000
event data recorder (EDR) reports retrieved from airbag
control modules. These reports typically indicate the airbag
deployment status and the corresponding Delta-V of each
recorded event. A prior study analyzing crash data in the
NASS database demonstrated the airbag deployment threshold
varies between vehicle manufacturers and over time. However,
the analysis was limited to Ford and GM vehicles due to insufficient
data. This paper expands on the prior study of frontal
airbag deployment thresholds by analyzing newer years of
NASS EDR data (4,000 additional reports). We found that the
Delta-V threshold for a 50% probability of deployment event
is higher for Toyota than for GM and Ford vehicles. Moreover,
SUVs and pickup trucks had higher deployment thresholds
than sedans. An increase in Delta-V thresholds was observed
for more recent vehicle model years. A higher Delta-V is
required for frontal airbag deployment in underride collisions,
in which a sedan contacted a vehicle with higher ground clearance
(SUV, pickup truck, or van), compared to collisions with
direct bumper-bumper engagement. Based on the findings,
we developed a logistic regression model that predicts the
probability of frontal airbag deployment with a known change
in velocity (ΔV = 0 to 45 mph), vehicle manufacturer (GM,
Toyota, Ford), vehicle type (sedan, SUV, pickup truck), model
year (1994-2001, 2002-2016), and impact configuration
(underride, bumper-bumper) with 82% accuracy. This study
provides information about airbag deployment behavior
beyond what is reported in owner’s manuals and National
Highway Traffic Safety Administration (NHTSA) guidelines.
rear-end collisions has previously been studied. It was found that the EDRs underestimated speed change in frontal collisions and
overestimated speed change in rear-end collisions. The source of the uncertainty was modeled using a threshold acceleration and bias
model. This study compares the response of Generation 1, 2 and 3 Toyota EDRs from Toyota Corolla, Camry and Prius models. 19
Toyota airbag control modules (ACMs) were mounted on a linear sled. The ACMs underwent a series of frontal and rear-end haversine
crash pulses of varying severity, duration and peak acceleration. The accuracy and trigger thresholds of the different models and
generations of EDRs were compared. There were different accuracy trends found between the early Generation 1 and the more modern
Generation 2 and 3 EDRs. There were also differences found in the threshold and trigger characteristics of the Generation 3 EDRs.
This study extends the understanding of how Toyota EDRs respond in low speed collisions with various collision parameters.
of collision severity in accident reconstruction applications.
The National Automotive Sampling System
(NASS) has provided a publicly-available database of realworld
motor vehicle collisions, including more than 10,000
event data recorder (EDR) reports retrieved from airbag
control modules. These reports typically indicate the airbag
deployment status and the corresponding Delta-V of each
recorded event. A prior study analyzing crash data in the
NASS database demonstrated the airbag deployment threshold
varies between vehicle manufacturers and over time. However,
the analysis was limited to Ford and GM vehicles due to insufficient
data. This paper expands on the prior study of frontal
airbag deployment thresholds by analyzing newer years of
NASS EDR data (4,000 additional reports). We found that the
Delta-V threshold for a 50% probability of deployment event
is higher for Toyota than for GM and Ford vehicles. Moreover,
SUVs and pickup trucks had higher deployment thresholds
than sedans. An increase in Delta-V thresholds was observed
for more recent vehicle model years. A higher Delta-V is
required for frontal airbag deployment in underride collisions,
in which a sedan contacted a vehicle with higher ground clearance
(SUV, pickup truck, or van), compared to collisions with
direct bumper-bumper engagement. Based on the findings,
we developed a logistic regression model that predicts the
probability of frontal airbag deployment with a known change
in velocity (ΔV = 0 to 45 mph), vehicle manufacturer (GM,
Toyota, Ford), vehicle type (sedan, SUV, pickup truck), model
year (1994-2001, 2002-2016), and impact configuration
(underride, bumper-bumper) with 82% accuracy. This study
provides information about airbag deployment behavior
beyond what is reported in owner’s manuals and National
Highway Traffic Safety Administration (NHTSA) guidelines.
rear-end collisions has previously been studied. It was found that the EDRs underestimated speed change in frontal collisions and
overestimated speed change in rear-end collisions. The source of the uncertainty was modeled using a threshold acceleration and bias
model. This study compares the response of Generation 1, 2 and 3 Toyota EDRs from Toyota Corolla, Camry and Prius models. 19
Toyota airbag control modules (ACMs) were mounted on a linear sled. The ACMs underwent a series of frontal and rear-end haversine
crash pulses of varying severity, duration and peak acceleration. The accuracy and trigger thresholds of the different models and
generations of EDRs were compared. There were different accuracy trends found between the early Generation 1 and the more modern
Generation 2 and 3 EDRs. There were also differences found in the threshold and trigger characteristics of the Generation 3 EDRs.
This study extends the understanding of how Toyota EDRs respond in low speed collisions with various collision parameters.