ollision C
Volume 16 Issue 1
The International Compendium for Crash Research
Investigation of EDR Data
From a High Speed Crash with 3D Simulation
Crashology: EDR Delta-V The effect of tire friction
Restitution, Impulse Space, and Orientations collisionmagazine.com 16.1-FrontCover.indd 1
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Contents
Volume 16 Issue 1
inside 4
Letter From the Editor
5
Collision Magazine Info and Advertiser Index
6
features 6
28
60 72
90 96
Investigation of EDR Data from A High Speed Crash with 3D Simulation by Brian G. McHenry
Analysis of the Event Data Recorder Information Obtained in Crash Testing of Supported and Pre-Supported Hyundai Vehicles
28
by Robert Anderson and Wesley Vandiver
Restitution, Impulse Space, and Orientations by Micky Marine
Analytical Method for Correcting the Delta-V Reported by Toyota/Lexus/Scion Airbag Control Modules by Robert Anderson, Michelle Hoffman and W. R. Rusty Haight
60
Development of a Test Procedure for Setting Non-Deployment (ND) Events by Chris Medwell
Crashology: Event Data Recorder Delta V: The Effect of Tire Friction by Wesley Vandiver and Robert Anderson
100 The 2021 and 2022 SATAI Crash Program by Robert Anderson
90
case study 46
Case Study: Verifying EDR Data from a Ram ProMaster 1500 Van Collision by Chris Medwell
106 Case Study Solution: Discovering and Explaining a CDR Data Anomaly by Chris Medwell
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Fo ll ow -u p
CA SE
PR OB LE M
Investigation of EDR Data from A High Speed Crash with 3D Simulation
Volume 15, Issue 2 of Collision Magazine contains a case problem article entitled "Did you find any errors when you read through the data?" by W. R. Rusty Haight & David W. Sersen
Brian G. McHenry McHenry Software Inc
ntroduction Volume 15, Issue 2 of Collision Magazine contains a case problem article entitled "Did you find any errors when you read through the data?" by W. R. Rusty Haight & David W. Sersen.
I
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The case problem documents a real-world crash, captured in part on video, where both involved vehicles have similar, nearly identical data sets. Both vehicles had EDRs (Electronic Data Recorders). Both vehicles were General Motors (GM) vehicles, both are "49CFR563 compliant" [1]
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in terms of the data sets recorded. They are from the same direct to module (D2M) cable family (the "F00K108454" D2M cable family of GM ACMs). The data translation reports for both are almost identical including much of the Data Limitations text. The most significant difference is the actual module variant. One vehicle – a 2013 Buick LaCrosse (Allure) – had what is identified as an "SDM10Pconti" airbag control module (ACM). The other involved vehicle, a 2017 Chevy Tahoe, had an ACM identified as a "SDM30-delphi." The first reason for a review of the case problem is the fact that the crash had some EDR (Electronic Data Recorder) anomalies, documented in the article, which demonstrate and caution that EDRs are not infallible, and you always must use caution when reviewing the EDR results. EDR data and information provide additional data for crash reconstruction which needs to be carefully analyzed in concert with other analyses and examinations to come to final conclusions on each individual crash reconstruction.
The article brought up many important issues which need to be considered and addressed when reconstructing a crash with one, or two, EDRs. EDRs tell part of the reconstruction story…they are a great additional piece of the crash reconstruction puzzle however they can and do have issues/failures and don't tell you everything you need to know about a crash. The referenced article [2] included possibilities for corruption or inadequacy of the EDR data due to proximity of the EDR to the crush zone (does it possibly move during the crash? ), collisions wherein the accelerations on vehicles may exceed the limitations of the maximum acceleration which can be recorded by the EDR (many have 50 g-unit limits which represent an approximation of the actual limit) and there are other items which also need to be considered. A second reason for interest in the subject crash is that although one vehicle was at an extremely high speed (>100 MPH closing speed), the combined speed is like what might be encountered in 2 lane at-speed highway crashes so the anomalies brought up in the article are applicable to many highway crashes.
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Analysis of the Event Data Recorder Information Obtained in Crash Testing of Supported and Pre-Supported Hyundai Vehicles: a 2015 Elantra Sedan and a 2012 Genesis Coupe Robert Anderson
Wesley Vandiver
Biomechanics Analysis, LLC
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Collision Forensics, Inc.
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A
bstract Hyundai and Kia automobiles have Event Data Recorder (EDR) functionality to record crashrelated data. The authorized distributor for the Global Information Technologies (GIT) America, Inc.’s EDR tool is available through Crash Data Group, which is also the authorized distributor for the Bosch CDR and Tesla EDR tools. Although the GIT EDR tools support Hyundai and Kia automobiles back to the 2013 model year, prior research has demonstrated that the GIT EDR tool can be used to obtain a copy of the EDR from most Hyundai and Kia automobiles back to the 2010 model year. However, using an EDR tool to obtain crash data from automobiles that are outside the supported model years, raises concerns that some or all of the EDR data has been properly translated.
This research expands upon a previous crash testing that was conducted as part of the Southwestern Association of Technical Accident Investigator’s (SATAI) 2020 Crash Conference. The prior crash testing investigated the appropriateness of the translation of speed and service brake status EDR data from a pre-supported Hyundai Genesis. As part of the 2021 SATAI crash program, the Genesis was subjected to two additional head-on collisions and GIT EDR supported Hyundai Elantra was subjected to 16 front and rear crash tests, while speed, service brake status, and additional parameters such as longitudinal and lateral vehicle acceleration and Delta V, and steering wheel angle were measured or observed to compare with that reported in the post-crash EDR report.
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PR OB LE M
Verifying EDR Data
CA SE
from a Ram ProMaster 1500 Van Collision Chris Medwell, PE
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I
ntroduction In most EDR data training classes, one of the themes you will hear from the instructor is: check and verify the EDR data. For example, we are taught to verify speedometer calibration by checking that the tire size on the vehicle is close to that programmed into the vehicle electronic system. Verifying also includes comparing the EDR data to other sources of the same information. To the extent possible, you should reconstruct the crash using crash physics like momentum or damage energy, to ensure the EDR data you plan to rely on is from the crash you are investigating and comports with the crash physics. If you have two EDR data records from vehicles that collided with each other, you should check whether the impact force on one vehicle roughly matches the impact force on the other [1]. If there is video footage of the crash you should check if the EDR data matches the video. Even though witnesses are often wrong about what they think they saw, you should compare the data and your reconstruction to what drivers and witnesses say about the crash. In short, you should compare the recorded EDR data with your “situationally complete” reconstruction calculations on both impact speed and ∆V to ensure that the data accurately reflects the crash physics so that no one can compare the facts of the crash to the data (or one aspect of the data to another aspect of the data) and say: “Wait, that doesn’t look right.” But what if it does not look right? What if the EDR data seems wrong? What do you do then? First, check your work. Then, check it again. Compare weights to specification sheets from more than one source. Vary your approach and/or departure angles by any reasonable values. Check the speed through other means. Do you have engine RPMs? Check if the vehicle can go that speed at that RPM. What gear would it have to be in? Does that comport with your other information? In most cases, if you cannot rationalize the EDR data to the reconstruction, it is going to be something wrong with the reconstruction or perhaps something wrong with the particular vehicle involved in your crash, as we theorized in the present case. Only in our case, we ended up discovering not something wrong with the crash vehicle, but something amiss with the OEM translation of the EDR pre-crash data. www.collisionpublishing.com
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Background Bloomberg Consulting was retained to investigate and reconstruct a fatal collision involving a 2018 RAM ProMaster 1500 cargo van and a HarleyDavidson motorcycle. The reported facts were that the motorcyclist had stopped in the roadway at an intersection, intending to make a left turn. While stopped, the motorcycle was struck from the rear by the van and propelled a minimum of 50 ft. (See Figure 1).
Figure 1: Scene photograph showing van and motorcycle at final rest The van driver braked to a stop after the collision and came to rest behind the motorcycle and rider. The van driver told the police that she did not see the motorcycle. The speed limit on the roadway was 55 mph and witnesses told the police that the van appeared to have been going about 55 mph and did not apparently slow down before the collision. Below is an outline of the facts developed during the initial investigation, to be used in solving this case problem: CDR Data The CDR data report from the van contained a non-deployment (ND) event record which indicated that the van had sustained a longitudinal ∆V of -6.8 mph in the collision. (See Figure 2). The Pre-Crash Data (5 seconds recorded at 10HZ) indicated that the van had been traveling in a steady-state condition for nearly the entire 5 s, with the recorded speed at 19-20 mph, the accelerator pedal at about 10%, and the engine at just under 1700 RPM. The driver braked about ½ sec-
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b osch C DR pr o to o l k it The Bosch CDR Tool is a reliable, versatile, and increasingly powerful industry standard platform that retrieves EDR data from the vast majority of modern vehicles. The CDR Tool software generates a detailed report that has become a vital part of investigations conducted by insurance claims adjusters and Special Investigative Units (SIUs). They are also routinely used by law enforcement agencies and accident reconstructionists. EDR data translated by the Bosch CDR Tool is admissible in court as the CDR reports are used to verify insurance claims and assess vehicle and driver input in the moments leading up to, and during, a crash.
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Schedule a webinar or product demo today www.crashdatagroup.com
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Restitution, Impulse Space, and Orientations Micky Marine SSi Phoenix, Inc. 60 Collision Magazine - Volume 16 Issue 1
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R
estitution The notion of a coefficient of restitution is one related to the energy loss between colliding bodies. In a collision, energy is dissipated through material plastic deformation as well as vibration, friction, internal material damping, etc. In general, the details of the energy loss processes are quite complex, and as a result, analysts turn to simplifying parameters like a coefficient of restitution to facilitate analyses. Dynamics textbooks often cover the subject of restitution in discussions of impulse-momentum methods within the context of smooth spherical objects impacting one another. This leads to the establishment of a convenient orthogonal coordinate system wherein one axis is parallel to the tangent at the point where the two spheres make contact, and the oth-
er is normal to this tangential axis and necessarily passes through the centers of mass of the colliding spheres. In the impact configuration depicted in Figure 1, the impulse between the spherical objects is considered to act normal to the surface tangents at the point of impact. To assist in characterizing the energy loss and restoration of the collision, a coefficient of restitution is employed, often as a ratio of the normal-component separation speed relative to the normal-component approach speed. Isaac Newton discussed this behavior, observed in experiments conducted with spheres striking one another, in his seminal work “The Mathematical Principles of Natural Philosophy” [1]; what is now widely known as a coefficient of restitution has also been referred to as Newton’s Experimental Law.
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Analytical Method foR Correcting the Delta-V Reported by Toyota/Lexus/Scion
Airbag Control Modules
Robert Anderson
Biomechanics Analysis
I
Michelle Hoffman
Forensic Injury Analysis
ntroduction In mid-2011, the Toyota family (Toyota, Lexus and Scion) of vehicles became Bosch Crash Data Retrieval (CDR) Tool supported with the release of Version 4.0 of the Bosch CDR Tool software and by the end of 2011, coverage had been extended as far back as the 2001 model year with CDR Tool Version 4.3.[1] Barrier crash testing of various Toyota vehicles began in late 2012 and the growing body of results were presented at the 2013 CDR User’s Summit, the 2013 SATAI Spring Conference, and the 2013 ARC-CSI Crash Conference. Consistent with testing conducted by other researchers, it was observed that an impact producing an acceleration with a magnitude of approximately 2 gs was required to wake the Toyota Airbag Control Modules (ACMs) and record an event. For Toyotas, like most other vehicles that are equipped with Event Data Recorders (EDRs) that have a similar wake up, AE, algorithm "wake up" or trigger threshold, there is a potential to under-report the magnitude of the delta-V due to not capturing and then not recording the portion of the delta-V that occurs before "wake up" or the "Time Zero" point.
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W. R. Rusty Haight
Collision Safety Institute
positive X-directed (rear-end) impacts, and under-reported in negative X-directed (frontal) impacts.[2,3] It is generally accepted that the discrepancy in CDR reported delta-V is the result of the ACM’s internal accelerometer not being zeroed, which produces an offset, or bias, in the accelerometer data. Consequently, even at rest, integrating the non-zero accelerometer signal will yield an everincreasing or ever-decreasing delta-V. In effect, the CDR Tool reported delta-V can be thought of as the delta-V from the impact plus or minus the accumulated speed change from the accelerometer offset.
In addition, by comparing the delta-V measured in crash tests to the CDR Tool reported delta-V, it soon became evident that, particularly in lowspeed impacts, the CDR Tool reported delta-V from Toyota GEN1 ACMs and 04EDR/GEN2 Camry and Yaris ACMs was over-reported in
To estimate the actual delta-V from that recorded by the ACM, the practice of adjusting the CDR Tool reported delta-V by an average or range of average errors has become common. Another method for estimating the actual vehicle delta-V from that reported by Toyota ACMs exhibiting accelerometer bias involves correcting the shape of the delta-V trace.[2] This analytical method is specified in SAE J211 as a requirement to correct data from non-zeroed accelerometers in crash tests.[4] The accelerometer data is corrected by shifting the acceleration data up or down until the integration trace of that acceleration produces the characteristic wave shape which flattens out or plateaus as the crash pulse ends. By way of demonstration, Figure 1 is an example of a set of corrected and uncorrected data.
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The Crash Hub Expert Directory The Crash Hub is a specialized expert directory for crash reconstructionists and traffic investigators. This directory allows the user the ability to search, review, and retain vehicle crash experts around the world. Our directory creates hundreds of leads for new cases! The Crash Hub is also much more than an expert directory site because each member of The Crash Hub has the ability to add meaningful content to the site in the form of articles, events, training classes, photo albums, and videos. The Crash Hub can also be used as job search site and a classified ads directory.
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Join Today www.thecrashhub.com
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Development of a Test Procedure for Setting Non-Deployment (ND) Events Chris Medwell, PE
Bloomberg Consulting
O
ngoing research into (1) the ND recording threshold for a particular ACM type; and (2) the accuracy and reliability of EDR pre-crash data makes the ability to repeatedly set ND events desirable. If one is to verify ND recording threshold, EDR-reported wheel speed, engine RPM, and other pre-crash parameters through testing, it is clearly advantageous to be able to set ND events without crashing into anything and without deploying expensive airbags and other restraint systems. If the intent is to assess pre-crash data, the ACM must remain connected to the vehicle that is the subject of the test when the event is triggered, which risks accidental deployments. Literature review Hallman – Nissan SUV EDR Recording Characteristics (2020 EDR Summit) Full scale vehicle crash testing focused on Nissan ACM recording threshold and recording order was carried out by David Hallman (et al) and presented at the 2020 EDR Summit in Houston TX. Prior reports included CDR recorded ND event data from Nissan vehicles in collisions with recorded ∆V less than 5 mph – including a 2012 Versa that had recorded a collision with no longitudinal ∆V and a lateral ∆V at 1 km/h. The stated goals of the testing were to: Determine the minimum threshold for a longitudinal ND event recording, determine the event recording order and compare to the Data Limitations, and compare the findings to previously collected data. Two types of full scale crash tests were carried out; vehicle-to-vehicle and vehicle-to-barrier. The six vehicle-to-vehicle tests involved a 2013 Nissan Pathfinder
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rear-ending a stationary Lincoln Navigator, with an incremental increase in the speed of the Pathfinder for each subsequent test. The Pathfinder was instrumented to accurately record its impact speed and ∆V for each test. After each test the ACM was downloaded to check whether the collision had been recorded. Test results found that vehicle-to-vehicle frontal impacts with impact speeds from 3 to 4.6 mph and ∆V’s up to 3.9 mph were not recorded by the ACM. The final test with a 6.2 mph impact speed and a -5.3 mph ∆V (per the instrumentation) was recorded in the ACM at -4 mph. In six frontal impacts with the concrete barrier, the Pathfinder did not record events with ∆V’s up to -4.9 mph but did record the last two tests which both showed ∆V’s at -5.5 mph. In three rear impacts with the barrier, a longitudinal ∆V at 4.9 mph was not recorded by the ACM. The last test with an impact speed of 5.1 mph and a ∆V at 6.5 mph was recorded in the ACM as 5 mph. While the Hallman testing verified the 5 mph ND event recording threshold for the test vehicle, further research into the ND recording threshold for other Nissan vehicles is suggested in order to understand the known examples of Nissan vehicles having recorded events with ∆Vs below that threshold. In order to create 4 recorded ND events in the ACM, Hallman had to source two vehicles, concrete barriers, a test facility and instrumentation, and carry out 15 vehicle crashes. At the conclusion of the testing, the cost to repair the test vehicles had been incurred or absorbed. Clearly, there is a research need to create ND recorded events, whether it is to verify pre-crash data, recording thresholds, or event recording order. A
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reliable method of creating these events without actually damaging the test vehicles could enable more costeffective research into these subjects. Bosch CDR Software Instructions for Bench Downloading “EDR Data Volatility” “When imaging EDR data with airbag control modules (ACM) or other ECUs removed from the vehicle with an EDR, always make sure that while the CDR Interface Module is connected to the ECU that it is sitting level, in
its upright position and does not get moved, turned over or dropped.” “While the CDR System is not capable of writing data to an ACM or ROS, when an [sic] either one are powered up using the CDR System, particularly when imaging them out of the vehicle, it may be possible to create a situation where the data stored in an event may be replaced with "data" stored during rough handling of an unsecured and powered up ECU. ACMs or ROS’s [sic] which are not adequately secured while powered up should always be treated as though the data is volatile and they should be powered down and left to discharge any stored electrical
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crash·ol·o·gy THE SCIENCE OF CRASHES Wesley Vandiver
Robert Anderson
Collision Forensics, Inc.
Biomechanics Analysis
Event Data Recorder Delta V: The Effect of Tire Friction
I
n addition to the constantly evolving Event Data Recorder technology, Toyota Vehicle Control History, Tesla diagnostic logs, GM Advanced Safety data, Subaru Eyesight, Berla iVe, etc. electronic data from automobiles is ever expanding and has become ubiquitous in motor vehicle crash investigation. While computers do not lie or exaggerate, there are circumstances when their recordings can be misinterpreted as to what they represent in the physical world. For example, it is well understood that skid, spin, hydroplaning, being airborne, etc. can result in pre-crash speeds that do not represent a vehicle’s actual over-the-ground speed. Similarly, in some circumstances to arrive at the actual collision force between vehicles and/or the ∆V to which vehicle occupants were subjected, the friction between a vehicle’s tires and the roadway must be accounted for. In order to properly apply Newton’s Laws, a tool known as a free body diagram, can be used to account for all the forces acting on an object by replacing an objects contacts with the forces exerted. Figure 1 shows the free body diagram for the Impala.
Conceptually, the Impala shown in Figure 1 is being decelerated by both the crash force Fc from the collision, and the frictional force Ff from continued hard braking and skidding during the impact. The frictional force is, Ff = W * Cf, the product of the normal force, which is the vehicle weight, times the coefficient of friction, or drag factor, between the tires and the roadway. Netwon’s 2nd Law, states that the net force, or the summation of forces is, ∑F = m a, the mass times acceleration. Average acceleration can be represented by ∆V/∆t, the change in speed divided by the collision duration. Therefore, substituting and rearranging, we get: 96 Collision Magazine - Volume 16 Issue 1
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∆Vtotal = (Fc + Ff ) ∆t / m ∆Vtotal = (Fc ∆t / m) + (Ff ∆t / m) ∆Vtotal = ∆Vc + ∆Vf Therefore, in this example the total Delta V of the Impala is the Delta V due to the collision force plus the Delta V due tire friction from hard braking and/or skidding. Another example is shown in Figures 2 and 3 where a Grand Marquis skid through an impact with a Honda CBR so that ∆Vtotal was a combination of the speed change due to skidding, plus the ∆Vc. This is shown graphically in Figure 3 where the acceleration shows the slowing that is the result of braking plus the superimposed slowing due to the collision. The two crash tests above are examples of how the tire friction from the bullet vehicle’s braking increases the Delta V experienced by that vehicle during the impact, and as measured by that vehicle’s own accelerometer within its airbag control module. Revisiting the first example, the free body diagram for the Corolla shown in Figure 4 illustrates how the net force acting on the struck vehicle is the collision force minus the frictional force. In other words, the friction of the struck vehicle’s tires on the roadway reduces the net force and therefore the resultant or ∆Vtotal. In 1990, Emori and Horiguchi set forth momentum equations with an impulse term to account for the friction between the tires and the roadway of the struck vehicle.[1] These equations were presented again in a 1998 paper in which the momentum equations were rearranged in terms of vehicle ∆V as shown in Figure 5.[2] With the impulse
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Figure 1: SATAI 2022 Test 6 Impala broadsiding a Corolla (Impala’s free body diagram)
Figure 2: IATAI 2019 motorcycle class Test 1 – Grand Marquis vs Honda CBR momentum equations written in this way, it can be seen how the impulse term from tire friction of the struck vehicle (∑Fext ∆t) decreases the struck vehicle’s ∆V while increasing the striking vehicle’s ∆V. Figure 5, conservation of momentum with an impulse term for tire friction on struck vehicle, where ∆V1 and ∆V2, are the Delta V’s of the bullet and target vehicles, m1 and m1, are the masses of the bullet at target vehicle, Vc is the closing speed, ∑Fext is the net external force from friction, and ∆t is the collision duration Indeed, the crash tests results presented in the 1998 paper not only showed a decreased target vehicle ∆V and increased bullet vehicle ∆V but the collision duration of the target was also decreased while the bullet vehicle’s collision duration was increased. Initially this might seem counter-intuitive. However, if the tire friction force is thought causing an offset to the vehicle’s acceleration, similar to that observed in early Toyota ACM’s due to
Figure 3: the Grand Marquis’ speed and acceleration
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or g Cr an as iz at h Te io st nal in g
The 2021 and 2022
SATAI Crash Program
Robert Anderson Biomechanics Analysis
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The Southwestern Association of Technical Accident Investigators (SATAI) is a non-profit training organization that typically offers two conferences per year. Both conferences have two days of classroom training, which count toward ACTAR CEUs. Once a year the conference includes a crash program, which is held at the Glendale Regional Public Training Center in Glendale, Arizona. As shown in Figure 1, the facility has a 500 by 800-foot test pad, which can accommodate a wide variety of vehicle handling and crash test demonstrations. The SATAI crash program went forward in 2021 though there were not conference meetings and the 2022 SATAI Crash Conference was held February 18-19.
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Case Analysis Solution:
CA SE So lu PRO ti BL on EM
Discovering and Explaining a CDR Data Anomaly Chris Medwell, PE
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A
man astride a Harley-Davidson motorcycle was stopped at an intersection (waiting for oncoming traffic to clear so he could make a left turn) on a straight, level rural roadway with a posted speed limit of 55 mph when his motorcycle was struck from behind by a 2018 RAM ProMaster van. The collision was recorded within the van’s Airbag Control Module and the EDR data was retrieved using the Bosch CDR Tool software (version 17.9.1) as a non-deployment (ND) event record. The event record included 5 s of Pre-Crash Data that reported that the van had approached at a steady speed of about 20 mph. The van’s driver told police that she had not seen the motorcycle. There was no heavy traffic, construction, other slow-moving vehicle, inclement weather, or any other reason why the van would be going 20 mph on a 55 mph highway. Witnesses told police that they thought the van had been traveling at about the speed limit and did not appear to have braked prior to impact. The motorcyclist was ejected during the collision and his head came into contact with the van’s windshield. (See Figure 1).
feet to stop following this collision? Calculate the post-impact speed of the van if the van was in fact braking hard for 50 feet post-collision. The CDR-reported speed of the van at (up to 0.1 s prior to) impact was 18 mph. Its maximum longitudinal ∆V is reported under System Status at Event as -6.8 mph (11 km/h) at 176 msec, and matches the data in the Longitudinal Crash Pulse table, which reaches -11 km/h at 176 msec and remains at that level for the rest of the data. The lateral ∆V is small enough to ignore in this aligned, inline collision. Therefore the post-impact speed of the van should be 18 mph – 6.8 mph = 11.2 mph (or slightly less). Use your favorite slide-to-stop formula to determine that (assuming 0.7 g drag factor) the van should stop in less than 6 feet of braking after impact. Using the same drag factor and assuming braking for 50 feet post-collision, the van’s post collision speed would have been 32.3 mph. Finally, the same slide-to-stop formula should tell you that if it takes 50 feet to stop from 11.2 mph the drag factor is about 0.084. (Is a drag factor of 0.084 consistent with skid marks at the scene?) Question 2: Calculate the ∆V for the motorcycle/ rider combination based on the CDR-reported ∆V for the van.
Figure 1: Bloomberg Consulting photograph showing van front end damage Solutions Question 1: Calculate the post-impact speed for the van based on the CDR-reported column titled “Speed, Vehicle Indicated” of the van and its recorded ∆V. Use this post-impact speed to estimate the required post-impact braking distance for the van to come a stop after the collision. Compare this distance to the 50 feet of maximum braking marks evident at the scene. What braking deceleration rate would be required for the van to take 50
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Again, the van’s maximum longitudinal ∆V is reported under System Status at Event as -6.8 mph. The van curb weight was 4776 lb and the motorcycle dry weight was 690 lb. For the purpose of our calculations we will add 200 lb to each vehicle to account for the driver and contents. The motorcycle’s ∆V is a positive value, since it was struck from the rear. So the equation becomes:
What stands out like a sore thumb in this calculation is this: if the van was only going 18 mph at impact, how could the motorcycle sustain a +38 mph ∆V? Hence, we have the next question: Question 3: Calculate the expected impact speed for the van based on the motorcycle and van ∆V’s determined in Question 2. Does anything stand out about the result of these calculations?
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Tesla EDR Tool Kit
EDR Data can be retrieved from all Tesla Model S, Model X, Model 3, and Model Y vehicles. Tesla Roadster, which was produced from 2008 to 2012, is equipped with a RCM but does not have an EDR.
The EDR Retrieval Hardware Kit for Tesla vehicles contains all the hardware required to download the Event Data Recorder (EDR) data that may be stored in all Tesla Model 3, Model S, Model X, and Model Y vehicles. This is the only kit that contains genuine Tesla EDR cables. Available at Crash Data Group www.crashdatagroup.com (800) 280-7940 crash@crashdatagroup.com
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Expert AutoStats®
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