Expertly Speaking

Tiger Woods Crash Reconstruction

Initial Tiger Woods Reports Are Misleading

Justin P. Schorr, Ph.D., Principal Collision Reconstruction Engineer

This analysis is based on publicly available data as of February 25, 2021.

Narrative 1: Dangerous stretch of roadway, lots of curves, lots of crashes. FALSE

The first piece of physical evidence consistent with a “loss of control” of the Genesis is found on the center median strip separating the northbound lanes of Hawthorne Boulevard from the southbound lanes. Taking this as the first point where we can say that the collision sequence had begun, the approach to this location is more or less a straight shot for just under 900 feet. The tip of the median is at the start of a long, gradual bend in the roadway to the right – though this bend has a critical speed in excess of 130 miles per hour (the maximum speed at which passenger vehicle operators could, if they so desired, negotiate the turn without leaving yaw marks) and accordingly is not of the nature which would cause an operator to lose control of their vehicle.

It should be mentioned that Hawthorne Boulevard northbound, in this immediate area, is on a downgrade which approaches 10%. This downgrade, while steep, can still be safely and easily navigated consistent with data from the California Statewide Integrated Traffic Records System (SWITRS) – a statewide database maintained by UC Berkeley – which shows that there were no other substantially similar collisions within an approximately ½ mile radius for the most recent 10-year period in which crash data is available (2010 – 2019).

[*This database includes, apparently, all California collisions where an injury, including minor ones, was reported (approximately 720,000 collisions between 2010 and 2019 in Los Angeles County). Within the noted radius (which does NOT include the intersection of Hawthorne Boulevard and Palos Verdes Drive), there were no reported collisions in the northbound travel direction (Tiger’s direction of travel) and there was one reported collision in the southbound travel direction. The southbound collision occurred in 2010.]

Here is a map showing the location of Tiger’s collision along with those in the Statewide Database between 2010 and 2019:

Tiger Woods Crash Analysis


Narrative 2: This was a “rollover” collision, as noted in many headlines.  FALSE

Based on the physical evidence available at this time, including photographs and video of the roadway markings, the damage to the vehicle, and the point of rest location and orientation – this data is NOT consistent with the current characterization as a “rollover.”

While the Genesis does indeed come to rest on its driver side, this is indicative of the vehicle overturning at the tail end of the collision sequence and not with an extended rollover event, as it is currently being characterized in the news reports.  There are no roadway markings consistent with the vehicle overturning prior to departing the west side of the roadway (this departure point being approximately 100 feet from where it ultimately came to rest and approximately 300 feet north of where the vehicle crossed the center median), and the damage pattern to the roof of the vehicle (where there is almost no damage) suggests that the vehicle did not complete a full rotation at any point. 

Rather, provided the principal direction of force consistent with the damage to the front of the vehicle (front to rear and centered towards the passenger side) and the damage to the foliage along the west side of the roadway (it appears a large tree/stump has been uprooted as a result of being struck by the Genesis), the data is consistent with the Genesis striking a tree/stump with its front, passenger side and then subsequently rotating in a clockwise direction consistent with the laws of physics.  This rotation, coupled with the uphill topography immediately west of where the Genesis came to rest, would introduce a substantive rotational force about the z-axis and promote the overturn onto the driver side.  

Here, it is important to point out that the majority of the damage to the Genesis’s front end and the only overturning in the collision sequence both occurred within approximately 20 feet of where the Genesis came to rest.  The data is consistent with the vehicle being upright from the point of the loss of control until it struck the tree – or approximately 95% of the 400+ foot travel path across the median and southbound side of the roadway much discussed in current news articles.

Tiger Woods Crash Reconstruction


What to expect moving forward:

One final misleading narrative I am hearing is that since there are no tire marks along the roadway, this is somehow evidence that there was no attempt to slow the vehicle at any point prior to or during the collision sequence.  The vehicle has anti-lock brakes which (by definition) prevent the wheels from locking.  Tire marks are left, typically, by wheels which are locked and sliding along the roadway.  As such, the absence of markings provides little to no information regarding the brake status prior to or during this collision.  With that said, the police have almost certainly already acquired what is known as “event data” from the vehicle, which will detail, at a minimum, the 5 seconds prior to airbag deployment through various data elements including speed, steering wheel angle, and brake status.  Depending on what that speed is (and there is nothing in terms of physical evidence which necessarily establishes the vehicle was traveling above the 45 miles per hour speed limit), this data may or may not capture the moments which preceded the initial loss of control.  However, depending on the capabilities of the police department conducting the investigation, there is likely additional pre-crash data which can be accessed through the infotainment system given that this is a brand-new vehicle with what I assume is the most advanced technology package Genesis has to offer.

Justin P. Schorr, Ph.D., Principal Collision Reconstruction Engineer with DJS Associates, Inc., can be reached via email at or via phone at 215-659-2010.

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SUV v. Gas Station Engineering Animation

Hugh Borbidge, BSME, Director of Engineering Animation



Synopsis: Engineering animations are an important and useful tool to help explain issues to a jury. This is especially true when there may be a language barrier. For this case, DJS was tasked with completing an engineering animation to demonstrate an incident that occurred when an SUV reversed and struck a gas station attendant.

Scene photographs provided points of rest and a trail of damage left from the event. Witness testimony contributed approximate initial positions of the SUV and attendant with regard to the fuel pumps.

To-scale computer models were built of the SUV, gas station attendant, and the gas station itself. With the available data, we reconstructed the sequence of events and created animation clips showing what had happened. After the motion was finalized, the incident could be viewed from any vantage point. The client utilized two perspective views for this case.

Result: Case settled out of court.

Hugh Borbidge, BSME, Director of Engineering Animation with DJS Associates, Inc., can be reached via email at or via phone at 215-659-2010.

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The Need for Speed: Obtaining Speed From Video

James R. Schmidt, Jr., BSME, Collision Reconstruction Engineering Analyst

You guessed it! If Jim Schmidt is writing something, it must be regarding speed from video! That’s because I’m passionate about what I do! They don’t call me “Captain Video” for nothing.

A new year. A new dash cam. A routine drive home in the evening. One thing leads to another, pushpins were plotted, speed was calculated, and wouldn’t you know it … the same results! Perfection!

Pushpins were plotted for 59 seconds and 0.6 miles of travel. A speed versus time profile was generated from this plotting, and a comparison was made with the GPS speeds shown on the dash cam display. Assuming for this example the GPS speed display to be the actual speed of the vehicle (which is a reasonable assumption for normal driving with gradual speed variations), the independently calculated speeds were within 2 mph of actual over this entire time and distance. Additional pushpins could be plotted to refine this even further.

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Stop Sign Obstruction: Was it the Cause of a Motorcycle Collision?

Justin P. Schorr, Ph.D., Principal Collision Reconstruction Engineer

Synopsis: A motorcycle was traveling southbound on a two-lane, two-direction roadway approaching a T-type intersection with a four-lane roadway. The motorcycle operator (plaintiff) failed to stop at the posted stop sign and entered the four-lane roadway where he was involved in a collision with a westbound vehicle.

The motorcycle operator testified he was traveling at the posted speed limit of 35 mph as he approached the intersection but, due to the stop sign being obstructed, perceived the traffic control at the last instant and did not have sufficient time and distance to stop prior to entering the four-lane roadway.

The plaintiff contended that tree branches obstructed the stop sign and therefore sued the State [the governing authority for the roadway], as well as the owner of the property on which the tree was located. The area of the collision was reportedly changed by the time suit was filed. The plaintiff provided no specific “hard copy” data, including photographs or measurements, to establish the obstruction or the extent of the obstruction.

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Heads-Up Displays: Aiding or Obstructing?

Laurence R. Penn, Senior Forensic Animation / Video Specialist
Justin P. Schorr, Ph.D., Principal Collision Reconstruction Engineer

The CES annual tradeshow (organized by the Consumer Technology Association) has been touted as the most influential tech event in the world – the place where revolutionary consumer technology is announced and displayed to the public. Since the first show took place in 1967, many products that seem old or nostalgic to us now were considered the highest of high-tech at the time when they were first announced. Such products included VCRs (1970), CDs (1981), HDTVs (1998), and drones (2015).

At the most recent CES show, which occurred virtually mid-January 2021, the newest technologies included vehicle heads-up displays or HUDs. With advances in miniaturizing and optimizing real-time 3D LIDAR scanning, their presence in new vehicles is becoming more and more prevalent. Combining real-time object collision detection and digital display technology, data can be displayed on dashboards or windshield to make drivers more aware of their surroundings or provide entertainment while the vehicle is in self-driving autonomous mode. In the demo videos of this new technology, “on-screen” alerts as well as visual cues are aligned with the actual position of a potential obstacle or hazard.

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The Drop-Off

Scott McMackin, P.E., Civil Engineer

Case Summary: A man operating his motorcycle entered a New Jersey interstate highway. The particular portion of the interstate was under construction, with the left and center lanes having been recently milled and overlaid. The motorcycle operator was traveling in the right lane, which was already milled and awaiting to be repaved. Upon attempting to change lanes, the driver lost control of his motorcycle and crashed, resulting in his death.

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