The first part of this presentation deals with some common, but misunderstood, problems within the NHTSA Crash Test data. This is then followed by three recent case examples. The first case illustrates how some of the misconceptions and problems can lead to an error in calculating speeds in the subject collision. The second and third example show why the crash investigator/reconstructionist cannot rely upon having EDR/CDR information available, and how crush analysis and other traditional methods can still provide "workable" information.	Download Crash Test Data and Common Misconceptions Presentation - 1 Slide per page
Selected videos from the 2023 Pennsylvania State Patrol conference that help to illustrate some of the issues and problems discussed in the first part of the presentation.	Videos from the 2023 PSP conference that help to illustrate the problems referenced in the first part of the presentation.
2023 Pennsylvania State Police Conference - Speed Calculation Spreadsheet	2023 PSP Excel Speed Calculation Spreadsheet
Video Presented by the District Attorney in Case Example 3	Video with commentary Video Slowed down and cropped for better viewing in the area of impact and immediately following Video Slo Mo 8th speed-No Commentary Video Slo Mo & Cropped No Comm
SCARS 2025 Video - Illustrates Impact location vs spin	Crash Test 1 - 6oclock camera Crash Test 1 - 7oclock camera Crash Test 1 - combined video Crash Test 2 - 6oclock camera Crash Test 2 - 7oclock camera Crash Test 2 - combined video
Case 3 Speed Calculation Spreadsheet	Case 3 Speed Calculation Spreadsheet
Speed Survey material. This has SPECIFIC applicability to California	Caltrans Speed Survey Manual 2018 Speed Survey 2021 Speed Survey

Web site References

Cloud Compare

https://www.danielgm.net/cc/release/index.html

Precision vs Accuarcy

The Science of Measurement: Accuracy vs. Precision

Practices of Science: Precision vs. Accuracy

What Is the Difference Between Accuracy and Precision?
Accuracy is close to a known value; precision measures repeatability

What is the meaning of accuracy and precision in Science?

In addition to the Presentation material, 4 Crash Tests were conducted at the

2023 SCARS Conference.

Crash Test 1

The first test featured an 18000 pound school bus traveling at a speed of ~ 28 mph into the rear of a Dodge Charger, driving the front of the Charger into as tree ....  

The "scenario" is a vehicle pulled off to the side of a road, stopped in the shade of a tree, to check directions ... or perhaps catch a nap.  

The School Bus then "straightens" the curve  .....

Bus into Charger into Tree

Crash Test 2

As part of the July 2023 Conference, tests 2 & 3 were designed as a series. The purpose was to see if the damage caused in the first crash in the series could be seperated from the dmage caused by the second crash in the series.

The scenario is as follows - Bus stop with its rear end hanging out into the travel lane of a cross street. This could be due to a ped crossing in front of the bus, or perhaps the driver stopped early to let some kids out.

The Impala then comes in anticipating the bus to move through the intersection, which it doesnt. Observe the motion of the bus, and picture the movements of any occupants inside might undergo, as well as what may occur if passengers were in the process of getting on or off the bus.

Impala into Rear axle of School Bus

Crash Test 3

As part of the July 2023 Conference, tests 2 & 3 were designed as a series. The purpose was to see if the damage caused in the first crash in the series could be seperated from the dmage caused by the second crash in the series.

Test 3, the second impact in the series, is the Dodge Charger into the rear of the Chevrolet Impala .... and again, this is supposed to be a "bam-bam" series .... where the Dodge Charger was following too closely behind to avoid the (secnd) impact into the rear of the Impala.

Charger into Impala into Rear axle of School Bus

Crash Test 4

For the last test in the July 2023 series .... it was a simple car travelling too fast for the curve and "straightens" the curve impacting the tree near the edge of the roadway.

Note the lack of damage to the tree.

Charger into Tree

The Expert VIN DeCoder and Expert AutoStats for the 3 Dodge Chargers and the Chevrolet Impala involved in the crash testing for the SCARS 2023 conference is available from the following link.

4N6XPRT Systems data sheets for the Crash Test Vehicles

Often times people ask "How accurate are the weights in Expert AutoStats?" the weight comaprison of the weights in Expert AutoStats compared to the actual weights of the crash test vehicles can be downloaded from the following link. Some of the factors that go into weight differences are - trim, engine, fuel tank size, "junk in the trunk",and even an extra coat of paint.

Weight comparison - Expert AutoStats weights compared to Acutal weights of vehicles

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4N6XPRT Systems Conference Material and Presentations Page