In some ways, motorcycle crashes are like any other crash, and attorneys litigating car crashes will already have a sense for where to focus their energy when they encounter a motorcycle crash. There are some unique elements of motorcycle crashes though, that attorneys will benefit from keeping in mind. This post covers some of those unique items.

Nathan Rose, Jacob Palmer, and Michael Erickson of Explico reconstructed a nighttime, left turn across path motorcycle crash involving a Chevrolet Malibu and a Suzuki GSX-R750 motorcycle. The Chevrolet turned left across the path of the Suzuki. The left-turning driver stated that she did not see the approaching motorcycle prior to initiating her turn. The officers located a GoPro camera at the scene, which had initially been attached to the motorcyclist’s helmet.

Recently, PC-Crash simulation software [1] incorporated a single-track vehicle driver model for simulating motorcycle motion. In the past, a two-wheeled vehicle in PC-Crash would simply fall over - it had no stability. With the single-track vehicle driver model, the model will generate the necessary steering inputs and lean for the motorcycle to follow a curved path while remaining upright and stable.

In a prior post, I examined how certain motorcycle characteristics affect the deceleration when the motorcycle is sliding on the road: fairings, crash bars, frame sliders, etc. That post did not address the influence of a wet road. In this post, I offer a technical note to document studies that have shown that a wet roadway reduces a sliding motorcycle’s deceleration.

One example of a roadway feature that could contribute to a fall by a motorcyclist is a longitudinal pavement edge. A longitudinal edge could be encountered by a motorcyclist as one side of a lengthy pothole or area of road deterioration. Another example occurs on a roadway that is being repaved, particularly when one lane has already been repaved and the adjacent lane has not. In such instances, the repaved lane may sit higher than the adjacent lane. A motorcyclist that maneuvers from the lower lane to the higher lane could encounter a longitudinal pavement edge of sufficient height to contribute to a loss of control and a capsize.

Crash reconstructionists are frequently asked to determine how a crash could have been avoided. In conducting this analysis, there will be instances in which an assumption will be made about the level of deceleration a motorcyclist should have been able to achieve. This post explores the decelerations achievable by motorcyclists.

Sometimes after a collision, a motorcycle’s speedometer or tachometer will exhibit a residual reading other than zero. In some instances, physical evidence will make it evident that the residual speed reading is not a reliable indicator of the motorcycle’s impact speed. However, if the motorcycle is equipped with a speedometer with a stepper motor, then there is the potential for the residual reading to be accurate and useful in the reconstruction.

For a three-wheeled motorcycle with two wheels in the rear, a greater percentage of the motorcycle’s weight is carried by the rear wheels and the weight transfer to the front of the motorcycle during braking is less significant than for a two-wheeled motorcycle. This changes the characteristics of the deceleration when an operator uses only the front brake or only the rear brake. The testing in this paper explores the significance of these differences.

Lane-sharing is the practice by a motorcyclist of sharing a lane with another vehicle. Lane-splitting is the practice by a motorcyclist of riding between streams of traffic by riding on or near the striping between lanes. The terms lane-splitting and lane-sharing are often used interchangeably. These practices, which are allowed in California, allow a motorcyclist to drive faster than the surrounding traffic in congested or stop-and-go traffic. They also give motorcyclists more options for how they position themselves on the roadway.

Crash reconstructionists are frequently asked to determine how a crash could have been avoided. In conducting this analysis, there will be instances in which an assumption will be made about the level of deceleration a motorcyclist should have been able to achieve. Based on the literature summarized here, motorcyclists would be able to achieve a deceleration of 0.5 g and above on a dry road by utilizing only their front brakes. By utilizing both brakes, most motorcyclists will be able to achieve a deceleration of 0.6 g and above on a dry road.