Tag Archives: Robert T. Lynch

IIHS Top Safety Rating to Include Better Headlights


Robert T. Lynch, P.E., Principal Collision Reconstruction Engineer

The Insurance Institute for Highway Safety (IIHS) has just announced that 2020 model year vehicles qualifying for the Top Safety Pick+ award need to have “good” or “acceptable” headlights as standard equipment. IIHS feels that this will encourage automakers to stop equipping vehicles with poor headlights that don’t light the road.

About half of all fatal crashes in the U.S. occur in the dark, and more than a quarter occur on unlit roads. The overwhelming majority of fatal pedestrian collisions occur at night. Headlights have an obvious role to play in preventing nighttime crashes, but not all headlights perform their job equally. Differences in bulb type, headlights technology and even the aim of the headlights all affect the amount of useful light on the roadway ahead.

continue reading

Automatic Emergency Braking Doesn’t Always Prevent Pedestrian Collisions

Breaking Technology

Robert T. Lynch, PE, Principal Collision Reconstruction Engineer

Automatic Emergency Braking (AEB) is generally designed to automatically apply the brakes when a rear-end vehicle collision is imminent. This technology has been shown to mitigate rear-end impacts; however, this technology is not always capable of detecting pedestrians crossing in front of a vehicle.

AAA has conducted testing of vehicles equipped with AEB and found that in 60% of the tests, the vehicle failed to stop, from an initial speed of 20 miles per hour, before striking the pedestrian dummy. The testing was performed during daylight hours with adult pedestrian dummies. The tested vehicle performed worse at higher speeds, under dark conditions, and with child dummies.

continue reading

The Importance of Event Data in Low Speed Collisions

Event Data Recorder

Robert T. Lynch, PE, Principal Collision Reconstruction Engineer ::::

All model year 2013 and newer vehicles equipped with an event data recorder (EDR) that are sold in the United States need to adhere to the requirements set forth in 49 CFR Part 563 of the federal standards.

Part 563 establishes minimum requirements for an EDR. In particular, an EDR must record an event if the vehicle experiences a Delta-V (change in velocity) above 5 mph from any direction: front, rear or side. When a vehicle sees a Delta-V greater than 5 mph, the EDR will record 5 seconds of pre-crash speed, braking, and acceleration data, as well as severity data for the impact itself.

continue reading

Mississippi Moon


Robert T. Lynch, PE, Principal Collision Reconstruction Engineer ::::

…won’t you keep on shinin’ on me

When evaluating nighttime collisions, a reconstructionist may choose to visit the accident location under similar conditions in order to observe the artificial light sources (i.e. street lights, nearby business lighting, traffic lights, etc.) to get a sense of what a driver could have seen leading up to a collision. Where a well-lit intersection could illuminate the roadway as if it had the appearance of daytime, a driver on a dark roadway may not have sufficient time and distance to perceive, react and avoid a dark-clothed pedestrian crossing the roadway.

While the historical moon data is researched and taken into consideration for a similar conditioned inspection, the moon is often not a factor in contributing to the overall useful illumination of the roadway. The definition of “useful” illumination is often taken to be an area of the roadway illuminated above 3.2 LUX, the dark limit of civil twilight (~30 minutes after sunset). Research has shown that beyond the limit of civil twilight, visual recognition functions deteriorate rapidly. The term “twilight envelope” has been coined to describe the useful extent of the vehicle headlight beam effecting a driver’s visibility at night.

continue reading

Inattentional Blindness

Motorcycle Blindness

Robert T. Lynch, PE, Senior Collision Reconstruction Engineer ::::

A person’s failure to notice an unexpected object located in plain sight is known as inattentional blindness. This phenomenon, rooted in the way the human brain processes (or fails to process) information, provides a framework to understand the looked-but-failed-to-see (LBFTS) crashes commonly associated with motorcycle collisions. LBFTS crashes are particularly troublesome because, despite clear conditions and the lack of other hazards or distractions, drivers will look in the direction of the oncoming motorcycle but still pull into its path. The brain must deal with a huge amount of sensory information during the driving task and cannot attend to everything due to the limitations of time and cognitive resources. The brain needs to decide what information is most important. The frequency of LBFTS crashes suggests that there is a connection with how the brain filters out information as motorcycles fall lower on the priority list for driving.

continue reading

Two Collision Contributors, One Code Violator


Robert T. Lynch, PE, Senior Collision Reconstruction Engineer ::::

A motorcycle traveled across the double yellow centerline into the opposite travel lane on a rural, two-lane roadway in order to pass a farm tractor. When the tractor turned left at the intersection a collision occurred. DJS Associates was retained to evaluate the matter to determine the contributing factors that led to the subject incident. The incident would have clearly been avoided if the tractor operator hadn’t turned left or if the motorcyclist decided not to pass the tractor at the intersection. So, in general, the actions of both operators could be considered as contributory. However, a review of the (Pennsylvania) state statutes indicated that the actions of the motorcyclist were in violation of the vehicle code while the tractor operator’s actions were in compliance with the vehicle code

The vehicle code requires that a left-hand turn be completed from the left-most lane available, and that the driver of a vehicle intending to turn left at an intersection yield the right-of-way to any vehicle approaching from the opposite direction which is so close as to constitute a hazard. From an engineering perspective, the actions of the tractor operator to turn left at the intersection from the travel lane were in compliance with the vehicle code.

continue reading
1 2 3 5