Who Was the Driver?

Collision Reconstruction Engineer

Robert T. Lynch, PE, Principal Collision Reconstruction Engineer
Case Synopsis: Four buddies went out drinking one night. While on their way home from the bar their vehicle departed the roadway to the right, as it was negotiating a left curve. The Event Data Recorder (EDR) in the vehicle indicated that the vehicle was traveling above the speed limit, at a speed above the critical speed for the curve, which resulted in the roadway departure and subsequent counterclockwise yaw before a frontal impact with a tree. All four occupants were unbelted, and three of the four occupants were ejected from the vehicle. Two of the ejected occupants were fatal. The one occupant that remained in the vehicle was the owner of the vehicle. The State Police conducted a criminal investigation to determine who was driving, concluding that it was the owner of the vehicle, the one who was not ejected. Continue reading “Who Was the Driver?”

When Collision Reconstruction Gets Personal

James R. Schmidt, Jr., BSME, Senior Collision Reconstruction Engineer
Recently, I was involved in a non-deployment crash while returning home from my parents’ house. Two-lane rural roadway. Nighttime, dry, clear conditions. No street lighting. Dark lighting conditions. And when I say it was dark, I mean it was dark … you weren’t seeing anything other than what was visible in your headlight range.
As I recall, I was cruising along at 50 mph, when a deer ran out in front of me. It came from my left, across the opposing lane of travel, and into my lane in a flash.

Wham, a collision occurred! I had absolutely no chance to avoid. No airbag deployment, but plenty of damage to my vehicle. Given the severity of the collision, I knew right away there was no chance that the deer survived (and that was, in fact, confirmed at the scene). I called 911 and was instructed by the police department to clear whatever was dragging from my vehicle myself, and, “move on my way;” but, that’s neither here nor there. Continue reading “When Collision Reconstruction Gets Personal”

Automated Work Zone Speed Enforcement in Pennsylvania

Road Work

Timothy P. Reilly, P.E., Collision Reconstruction / Civil Engineer
Pennsylvania officials have recently announced a new Automated Work Zone Speed Enforcement pilot program and the vehicle-mounted camera and radar devices are already operational in several work zones across the state. The Pennsylvania Department of Transportation, Pennsylvania Turnpike Commission, and Pennsylvania State Police are partnering in the program to reduce speeding in work zones to improve safety for workers and drivers.
The cameras will automatically capture a picture of the license plate when the radar detects a vehicle travelling 11 miles or greater over the speed limit in an active work zone. Violation notices will be then sent via mail according to the vehicle’s registration address. For the first offense, the owner of the vehicle will simply receive a warning. The penalty for the second offense is a $75.00 fine. Subsequent penalties will be $150.00 fines. Work zones utilizing these vehicles will have signs warning drivers and there will be a website where drivers can track the location of these vehicles. Continue reading “Automated Work Zone Speed Enforcement in Pennsylvania”

Dukes of Hazzard Jump… In A Minivan


Robert T. Lynch, PE, Sr. Collision Reconstruction Engineer ::::
A stake body pickup truck, towing a landscape trailer, was parked on the right shoulder of a two-lane roadway on a clear, sunny day. The lawnmowing equipment in both the bed of the truck and the trailer had been removed. There was no rear gate for the stake body, and the ramp to the trailer was down. Along came a minivan that drifted onto the shoulder of the roadway and hit the ramp square-on. Tire marks were observed on the wooden boards affixed to the sides of the trailer and stake body, showing the path the minivan took through the air. Scrape marks were also observed to the roof of the pickup truck where the underside of the minivan grazed the roof during its flight. Other than these minor markings, the pickup truck and trailer sustained no significant damage. The minivan landed in front of the pickup truck on the shoulder of the roadway, coming to rest on all four tires where it then caught fire. Fortunately, the occupants of the minivan were able to get out of the vehicle before sustaining further injury from the fire. The minivan sustained no significant crush damage. Continue reading “Dukes of Hazzard Jump… In A Minivan”

“Ride on Red” Law in Pennsylvania


Robert T. Lynch, PE, Senior Collision Reconstruction Engineer ::::
For over a year now, a new law in Pennsylvania has allowed for any vehicle (i.e., car, bicycle, motorcycle, even a horse and buggy) to proceed with caution at an intersection if the traffic signal’s vehicle-detection system fails to recognize it. The traffic signal should be treated like a stop sign in this scenario. However, the law DOES NOT mean you can treat any red light as a stop sign, only those that are “out of operation” or “not functioning properly.” The specific law, Pennsylvania Title 75, Section 3112(c), does not define how long a motorist must be sitting at a red light before it’s considered to be malfunctioning, but PennDOT and Pennsylvania State Police encourage drivers to use common sense. The signal has to be obviously malfunctioning, such as going through several cycles without giving you a green light. Continue reading ““Ride on Red” Law in Pennsylvania”

California to Allow Testing of True “Driverless Cars” on Public Streets by Summer 2018

Robert T. Lynch, PE, Sr. Collision Reconstruction Engineer ::::
Currently, regulation of autonomous vehicle (AV) testing and operation on public roadways in California, and most other states, requires a “safety driver” to be behind the wheel to take control of the vehicle in the event of an emergency. A proposed new set of rules, to take effect next year, will allow for testing of fully autonomous vehicles on the road without needing a safety driver. While a necessary step towards a world where autonomous vehicles are projected to be commonplace within the next couple of decades, this is a big win for the AV community as the technology rapidly advances towards a state of full autonomy.
Since 2012, California has enacted regulations pertaining to self-driving vehicles and technology. The state plays a big role when it comes to regulating the technology, as it is where a lot of the AV research and development is occurring. Currently, there are 42 auto manufacturers and technology companies testing 285 self-driving cars throughout the state. Other states are expected to follow California’s lead, as they have with prior regulations of AVs. Continue reading “California to Allow Testing of True “Driverless Cars” on Public Streets by Summer 2018”

“My Maserati does one-eighty-five…”

Robert T. Lynch, PE, Sr. Collision Reconstruction Engineer ::::
We’ve all experienced it – you’re driving on the highway minding your own business, when a vehicle surprises you as it suddenly passes you at a high speed. Your first reaction (after your heart stops racing from the initial shock) is to look to see if there is a police officer around to pull the driver over for speeding. Your second thought is… wondering just how fast the vehicle was going. Well, wonder no more. I’m going to outline a simple approach for you, rooted in basic physics, that allows you to reasonably estimate the speed of the vehicle. I know some of you get apprehensive when you read the word “physics,” but don’t be afraid, as this process works for even the non-engineer.
Here’s what you do… as soon as the vehicle passes your vehicle, start counting to 10, as if you’re playing hide-and-go-seek, counting the numbers out as seconds. When you get to 10, note the location of the speeding vehicle ahead of you. Roadside poles or painted white dashed lines on the roadway provide good visual cues in order to determine how far ahead the speeding vehicle has traveled in the 10 seconds since it passed you. We’ll call this the “10-second location.” Now, without stopping your rhythm of counting, continue on to 11… 12… 13 seconds… until your vehicle has now reached the same location where the speeding vehicle was after 10 seconds. If it takes you 13 seconds to cover the same distance that it took the speeding vehicle to cover in 10 seconds, the speeding vehicle is going approximately 30% faster than you; 14 seconds equates to 40% faster and 15 seconds equates to 50% faster. As an example, if you are traveling at 60 miles per hour and you count to 14 seconds when you reach the “10-second location,” the speeding vehicle was traveling 40% faster, or at a speed of approximately 84 miles per hour! Continue reading ““My Maserati does one-eighty-five…””

What Direction Was the Vehicle Traveling – An Analysis of an Intersectional Collision

Steven M. Schorr, PE, President, DJS Associates, Lead Collision Reconstruction Engineer ::::
A collision occurred, at a stop controlled intersection, between the front of a motorcycle and the driver (left) side of a passenger vehicle. The police took photographs of the point of rest of the vehicles and of the damage to the vehicles. Simple enough, right? Well, not so fast. When the police interviewed the involved parties, the operator of the passenger vehicle said she was northbound on the two lane, two direction roadway and was turning left to head westbound onto a one-way street when the northbound motorcycle, traveling in the same direction she was traveling, came up on her left side in the opposite lane trying to pass her. The motorcycle struck her driver side door as she was turning. The motorcycle operator informed the police that he was indeed northbound; however, as he approached the intersection, the passenger vehicle entered the intersection from his right, traveling westbound on the one-way street. As the passenger vehicle entered the intersection, it “cut him off” resulting in his motorcycle contacting the driver side of the passenger vehicle. Continue reading “What Direction Was the Vehicle Traveling – An Analysis of an Intersectional Collision”

Watch Where You Stand

Off-Tracking of Right Turning Tractor-Trailer

Steven M. Schorr, P.E., President of DJS Associates ::::
A tractor-trailer operator was executing a right-hand turn at a four-way intersection in a major city. As he was completing his turn and heading straight down the roadway onto which he turned, he was flagged down by a person who advised him that his truck contacted a pedestrian.
The physical evidence indicated that indeed the right side of his trailer did contact the pedestrian and knocked him down whereupon the pedestrian was run over by the right rear trailer tires of the right-turning tractor-trailer.
These dynamics are consistent with the properties of a right (or left) turning tractor-trailer wherein the tractor pulls the trailer. The trailer itself has no steering therefore as a result, in a right-hand turn, the right rear tires of the trailer will always track to the inside of the path of the right front tires of the tractor. This concept is referred to as “off-tracking”. The longer the trailer, the further to the inside (of the front tractor tires) the rear trailer tires will “off-track”. Continue reading “Watch Where You Stand”