Article

In this case, a cyclist on a city street encountered a power company grate in the street, his front tire went into a gap in the grate, he crashed and was injured. Robson Forensic was retained to determine if the grate was dangerous in a manner that caused the crash.

Case Description

A cyclist on a city street encountered a power company grate in the street, his front tire went into a gap in the grate, he crashed and was injured.

We inspected the grate and showed that ordinary bicycle tires could readily be trapped by the gap, that the gap was in a normal bicycle travel path and that cyclist activity was common in the area. We also showed that gaps such as this have been known for a long time to be dangerous to cyclists, and that the gap made the grate dangerous in a manner that was a cause of the cyclist’s crash and injuries.

This event was typical of other bicycle collisions. The case resolved through settlement.

Report Excerpts

Redacted report available in the “Details” section of this page.

1. INTRODUCTION

This bicycle crash occurred on June 22, 2006, on Maple Street, in Glens Falls, New York. The crash involved a bicycle operated by Derrick *******, and a grate owned by National Grid. ******* was injured as a result of the crash.

This investigation was performed to determine if the grate was dangerous in a manner that caused the crash.

3. THE CRASH

The police report:

… spoke to ******* who stated that he was riding his bike and his front tire went into the NIMO grate causing him to go over the handlebars.

The photos show *******’s bicycle to be a touring type bicycle. There are drop handlebars and multiple gears, a large seat and rear luggage rack. The photos showing ******* are of his head.

Head injuries are consistent with pitching over the handlebars when the front wheel is suddenly stopped.

4. CRASH SITE

The grate encountered by ******* is part of two similar installations in the westbound travel lane of Maple Street, between Ridge and Bay Streets. The grate that his tire entered is located across the street from the Adirondack Trust Company.

Maple Street is a 30-foot wide, urban local street. There are curbs and sidewalks, both sides. Parking is permitted, both sides. The surface of Maple Street is asphalt. The surface is marked with a double yellow centerline, white edge lines delineating parking spaces along the curbs, and cross walks. There was an in-street pedestrian sign at the crosswalk immediately west of the incident grate at my inspection. The City library and bicycle racks are located immediately south of the incident grate.

The involved grate is within the concrete top slab of an underground vault. The top slab is flush with the surrounding asphalt pavement and has an embedded steel frame supporting multiple grates. The grates are sized such that there are longitudinal (i.e., parallel to the direction of traffic) gaps. Within the concrete slab there are two rows of grates. For *******’s direction of travel, his tire went into a gap in the far grate. The gap is 4’ from the edge lines. The grate is 3’3” along the direction of travel. I measured the gap to be 1-1/16” wide. There was a piece of wood in the gap at my inspection. The photos I was provided show the front wheel of *******’s bicycle down in the grate. I replicated this entrapment at my inspection with a 27 x 1-1/4” tire. This is not the narrowest of tires.

The following photos show a typical bicycle wheel in the gap and the location of the grate in the street.



5. PARALLEL DRAINAGE GRATE GAPS ARE RECOGNIZED AS DANGEROUS TO BICYCLES

The hazard posed to bicyclists by parallel bar drainage grates and recommended methods to minimize that hazard have been recognized since at least 1974.

The USDOT 1974 Bikeways - State of the Art discusses the hazard posed by parallel bar grates when the bars are oriented parallel to the normally expected direction of travel,

Drainage grate problems have been well publicized. Most cycle tires and rims will drop through commonly employed parallel-bar grates, damaging wheel rims and giving unwary cyclists a nasty, over the handle-bars spill. [82]

The USDOT report further states:

Some communities have welded transverse bars over existing parallel bar grates to protect cyclists, others have employed transverse bar or honeycomb designs. [82] Every effort should be made to avoid the use of the hazardous parallel bar grates in areas where cyclists are likely to be riding. [84]

6. FINDINGS

Within the bounds of reasonable engineering certainty, and subject to change if additional information becomes available, it is my professional opinion that:

  1. ******* was injured when the front wheel of his bicycle was entrapped in a gap in a National Grid grated facility.
  2. The gap was 39 inches long by 1-1/16 inches wide, oriented parallel to the direction of traffic and at a location in the street where bicyclists should be expected to ride.
  3. The gap in the National Grid grate created a condition long recognized as dangerous to cyclists, and made the National Grid grated facility dangerous in a manner that caused this crash.
  4. Those responsible for the design, operation, and maintenance of the National Grid grated facility in Maple Street, should have recognized the unsafe condition created by the gap in the grates with the opening parallel to the direction of travel, and should have corrected same.
  5. Failure to design, construct and maintain the National Grid grate without a gap that would predictably entrap bicycle wheels was contrary to established national and state standards and made the National Grid grated facility dangerous in a manner that caused this crash.

Redacted report available in the “Details” section of this page.

 

Featured Expert

During the past 25+ years, Lance has provided field investigations, analysis, written reports, deposition and court testimony for several hundred motor vehicle, pedestrian, bicycle and train collisions related to roadway, parking lot and transit issues, as well as reconstruction of the collisions. Lance is licensed as a Professional Engineer in several states, and he maintains a number of professional affiliations, including the Transportation Research Board, the Institute of Traffic Engineers, and the Society of Automotive Engineers.