Tag Archives: Robert T. Lynch

Reconstruction of a Vehicle-Bicycle Collision


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

A doctor would frequently ride his bicycle from his home to the train station as part of his commute to work. One morning before sunrise, the doctor was riding along on a sidewalk before he crossed a six-lane roadway where he was struck by a vehicle after nearly crossing all six lanes of traffic.

Surveillance video was provided from a nearby business that captured the pre-impact movements of both the bicyclist and the vehicle. However, this video did not capture the actual point of impact, as the camera was located too far away (over 500 feet), and several trees were obstructing the clear line of sight. Also, the ambient illumination was still dark, effecting the clarity of the video.

DJS was asked to use the provided surveillance videos to reconstruct the incident to the greatest extent that it could be reconstructed. The roadway was documented with high-definition surveying (HDS) laser scans, drone aerial images and video, and terrestrial photographs and video, with specific focus on documenting the environment in the vicinity of the surveillance cameras. Using this data, an accurate, to-scale, three-dimensional model of the environment was created. The surveillance video was then camera-matched to the environment. The movements of both the bicyclist and vehicle were tracked through the environment and pre-impact speeds were able to be determined.

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Riding the Wrong Way at Night


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

An adult bicyclist was traveling at night on the left side of a 40-mile-per-hour, two-lane roadway with little to no shoulder when he was struck by the passenger side mirror of a passing vehicle. The bicyclist sustained an injury to his right arm. An investigation revealed there were no active lights on the bicycle, only retroreflectors.

The bicyclist brought suit against the driver for not avoiding the collision. An expert for the bicyclist opined that even though the bicyclist was in the wrong for riding on the left side of the roadway without a headlight, the vehicle operator should/could have observed the retroreflectors, understood their meaning, and avoided the collision. The vehicle operator had a minimal insurance policy which was tendered; however, the bicyclist brought an underinsured motorist (UIM) claim against his own insurance company.

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May is Motorcycle Safety Month


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

As the warmer weather approaches, more and more motorcycles are hitting the streets. Coming out of the winter months, where you would rarely see a motorcycle in operation in the northern half of the country, automobile operators must retrain their brains to specifically “Watch for Motorcycles.” In particular, drivers should take an extra moment to scan the oncoming lane for motorcycles prior to executing a left turn. Intersections introduce the greatest potential for vehicular conflict, and not surprisingly, account for the overwhelming majority of motorcycle (and automobile) collisions.

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Crossing Roadways at Night


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

It is no secret. Pedestrians crossing a roadway at night can identify the headlights of an approaching vehicle much easier than it is for a driver to observe pedestrians. However, research on drivers’ recognition distances indicates that a vehicle operator can identify a pedestrian crossing right-to-left from a greater distance than a pedestrian crossing from left-to-right. This is largely due to the requirement for low beam headlights to be angled more toward the right side of the roadway to prevent unnecessary glare for oncoming vehicle operators (SAE J1383).

To put this in perspective, a vehicle being operated at 25 miles per hour at night requires approximately 100 feet of total distance for a driver to perceive a hazard, and then react to the hazard by applying full braking to come to a stop. The nighttime recognition distance research indicates that a pedestrian wearing dark clothing crossing left-to-right is not identified by the average driver until the vehicle is less than 100 feet away, rendering the incident unavoidable for the driver. On the other hand, a pedestrian wearing dark clothing crossing from right-to-left is identified by the average driver at a distance greater than 100 feet, allowing the driver enough distance to perceive, react and avoid the pedestrian. Pedestrians in light-colored clothing or retroreflective material are observed by drivers at greater distances.

When crossing a roadway at night, the drivers approaching your location from your left can see you from a greater distance than those approaching from your right. Regardless, it is best for a pedestrian to use safe practices when crossing a roadway at night and always assume that vehicle operators cannot see you. Wait for a sufficient clearance in traffic (from both directions), or ensure that the vehicles have stopped or are stopping to allow you to cross.

Robert T. Lynch, P.E., Principal Collision Reconstruction Engineer with DJS Associates, Inc., can be reached via email at experts@forensicDJS.com or via phone at 215-659-2010.

Does Wearing Yellow Glasses Improve Nighttime Visibility?


Yellow Sunglasses

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

Despite claims that yellow glasses improve night vision, a recent study by Harvard researchers indicates that subjects wearing yellow glasses at night responded a fraction of a second slower than those not wearing the glasses.

Yellow glasses filter out blue light, which tends to get scattered more than red light due to its shorter wavelength. This scattering of blue light is said to contribute to headlight glare; so, the theory behind yellow glasses is that by filtering out the blue light, the glare is reduced, and night driving is improved. However, the white light emitted from vehicle headlights is made up of all the wavelengths of the visible spectrum, and by filtering out blue light, the total amount of light reaching the eye is reduced.

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IIHS Top Safety Rating to Include Better Headlights


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.

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