Bicycle Crashes Involving Light Rail Tracks Expert Article

In cities with streetcars, trolleys, trams, or other light rail systems (or remnants of abandoned rail systems), the tracks embedded in roadways are a known hazard for bicyclists, potentially resulting in wheel entrapments or loss of control. This article discusses some of the issues typically considered in relevant forensic investigations, including the anatomy of embedded rails, available safeguard options, and other methods used to notify cyclists and promote public safety.

bicycle rail track crash expert

Embedded Tracks, Flangeway Gaps, and Bicycle Crashes

The embedded rails used for light rail systems include a flangeway gap, or depression, running alongside the length of each steel track. This gap is designed to accommodate the streetcar’s wheel flange as the trolley or tram rolls along the rail, but the dimensions of a typical flangeway gap make it a potential hazard for narrow wheels, canes, or the foot of a pedestrian.

Rail Wheel Flange Gap Cross-Section - Bicycle Wheel Entrapment Hazard

The size and depth of the gap, relative to the width of the bicycle tire, determines how a bicycle will be affected:

  • Deflection - If the gap is wide enough for the tire to roll within, and deep enough to deflect turning forces, it is likely that the rail will impart an unintended, external turning force. The rider can no longer control the direction of the bicycle or maintain balance often resulting in a crash.
  • Entrapment - If the width of the gap closely aligns with the width of the bicycle tire, it is possible for the tire to become pinched, or entrapped, which can arrest the rotation of the wheel. This sudden and unexpected deceleration often throws the rider from the bicycle.

Both deflection and entrapment of a bicycle wheel can result in a crash. These incidents are typically more perilous where the front wheel of the bicycle interfaces with the flangeway gap. Bicycle crashes of this kind have the potential to be fatal, not only as a result of impact injuries, but also from the rider being thrown in an area with motor vehicle traffic and getting hit and/or run over.

Protection of Flangeway Gaps

There are a number of methods used by municipalities to reduce the prevalence of injuries related to embedded tracks, which include guards, re-routing pedestrian and bicycle traffic away from potential danger zones, posting warnings to alert the public to potential danger, and public outreach and education. The solution appropriate for each application is dependent upon a number of specific environmental conditions.

Compressible Rubber Flangeway Filler

A common method of protecting against wheel entrapments and other mishaps, is the installation of compressible rubber flangeway filler. Flangeway filler provides a nearly flush surface for bicycles and pedestrians to traverse, but compresses under the weight of the streetcar’s wheel flange, allowing for normal transit operation.

Flange Gap Filler Diagram - Bicycle Wheel Entrapment Hazard Mitigation

Flangeway filler is used by many municipalities in locations where bicycle and pedestrian traffic is expected.

Orientation of Tracks to Bicycle Lanes

The risk to cyclists is minimized when bicycles approach at, or near, a perpendicular angle to an embedded track. The Manual On Uniform Traffic Control Devices (MUTCD) provides guidance on bicycle lanes crossing over tracks, and in those cases, crossings are designed to be as close to a right angle as possible.

Bicycle Lane Highway Engineering Expert Diagram

As a result of the safety achieved from perpendicular crossings, in some instances bicycle lanes will diverge from vehicle travel lanes. Where this is done, colored pavement can be used to guide cyclists. Because of the known hazards, it can be unreasonably dangerous for bicycle lanes to run in close proximity and parallel to embedded rails.

The MUTCD does not provide specifications or guidance on designing for bicycle travel parallel to these roadway features.

Warning Signs

Warnings signs should be used to alert cyclists to impending hazards. Placement of signs should be determined to draw attention and permit adequate time for response. The specific requirements will vary based on environmental conditions, but warnings should be composed of readily available sign panels that convey an easily recognizable representation of the hazard present.


Bicycles are Vehicles

Bicycles are vehicles and, unless specifically prohibited, have the same rights to the roadway as motorized vehicles. They will travel in a designated bicycle lane (when available), but it is accepted practice, and sometimes necessary, for bicycles to be ridden on other portions of a roadway, such as when turning, passing vehicles, or avoiding hazards.

The specific actions of a bicyclist within the context of an incident will often be evaluated by a specially qualified bicycle expert.

For more information on bicycle experts at Robson Forensic, please visit our Bicycle Forensics page.

Investigating Bicycle Crashes Involving Embedded Tracks

In a case where a bicycle crash has resulted from an entrapment in a streetcar or light rail track, the Highway Engineering experts at Robson Forensic have the credentials and experience to examine whether the design, construction, or maintenance of the street, pavement, and track adhered to the applicable codes, standards, and regulations.

Please submit an inquiry or call us at 800.813.6736 to determine which expert is most appropriate to assist on your case.

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Michael J. Tuttman, Civil Engineer, Highway & Bridge Engineering Expert

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Civil Engineer, Highway & Bridge Engineering Expert
Michael has more than 25 years of engineering and design experience in a diverse group of civil engineering disciplines including transportation design, heavy construction, design-build projects,… read more.


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