38 Trial Lawyer • Fall 2022 Mark Ginsberg By Mark Ginsberg Modern cycling is measured, com- pared and quantified in ways that are more complete and subtle than ever before. Some is done privately and some publicly (such as online ride tracking apps). Understanding the strengths and shortcomings of available technology helps us better represent cyclists and athletes when they are injured. Bicycle mounted computers have existed in some form since the 1980s, but the advances and amount of available information that is stored and retained is important for any attorney who handles bicycle, jogger and walking litigation. Early bicycle computers showed real time speed data. Most showed total distance covered. The fanciest early models even showed average speed. Early computers were an advancement from cable driven speedometers. Almost all early computers used a magnet attached to the bicycle wheel. A computer sensor would measure speed and distance based on the passing of the magnet. While these were an improvement, they also required calibration based on the actual size of the wheel of the bicycle on which the computer was mounted. Changing tires or even wheel size (between a “road” and a “mountain” bike for example) required recalibration. Modern GPS enabled units don’t need wheel size calibration, but they do bring new accuracy limitations. One of the largest shortcomings of early generation cycling computers was the lack of substantial memory. After a ride, early computers could tell you how far the ride was and how long it took, maybe the average speed of the ride, and that was about it. Their data could not be downloaded, nor did they have the ability to show the rider’s route. Modern cycling computers have solved most of these issues. Advocates must understand the parts of modern cycling computers and how they measure data to be effective. The information can help us fill in missing pieces of a crash, and can even tell us if we think the crash is not one where we can prevail for the cyclist/potential client. Modern cycling computers have advanced to the point where even a relatively inexpensive unit measures more, and with more accuracy, than even the top of the line model from a decade ago. Understanding what is measured, and how, is of critical importance. We will address cell phones and apps on phones below, as these are also common and have some overlap with cycling computers (the Strava app can run on either). Modern cycling computers usually use GPS to measure speed and distance. They are not tied to the bicycles tire size for information. Many computers measure power as well. The power measurement can be used to show whether a cyclist was pedaling, how much power was applied to the pedals or if the rider was coasting. As outlined below, our office was able to use a power meter coupled with a cyclist computer to show that a cyclist stopped at two back-to-back stop signs in rural Oregon. Power can be actually measured, or it can be estimated depending on the system. Systems that measure actual power can be located in the rear hub, the bottom bracket or even the pedals themselves. If power output will be an issue in the claim, be sure to have the client tell you what system they are using and confirm that it was calibrated and working correctly. Some cycling computers and some apps do not measure power, but in essence reverse engineer the power based on speed, coupled with other previously provided information (height/weight of the user, type of bicycle, type of terrain). While Strengths & limitations of modern cycling tools Bicycle based technology
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