Bicycle Railing Height Report - AASHTO - Subcommittee on Design

DETERMINATION OF APPROPRIATE RAILING HEIGHTS FOR BICYCLISTS
NCHRP 20-7 (168)
Summary
A reference to “aesthetics” is used extensively in the preference of a 1.1-meter (42-inch)
height railing over a 1.4-meter (54-inch) railing. However, no attributes related to form
or scale have been identified as the determining factor in the objection to the 1.4-meter
(54-inch) height. It would be difficult to assess the aesthetics of a railing system without
understanding the setting and surrounding visual environment.
The more pertinent issue of visual impact occurs when a railing is placed within a scenic
view, and man-made objects can be visually offensive. In this regard, the smaller 1.1-
meter (42-inch) railing height may have less of an impact than the higher 1.4-meter (54-
inch) railing height.
Additionally, a 1.4-meter (54-inch) high railing would have a greater impact on the sight
line of users of a bikeway than a 1.1-meter (42-inch) high railing.
Cost
During the study process, the cost of bicycle railing was cited as a reason supporting a
lower railing height. However, no cost figures or cost thresholds were received from the
information acquired during the survey or telephone outreach. As such, a cost
comparison was conducted to assess the costs associated with the different railing
heights.
Due to the heavier materials necessary for vehicular loadings, the cost of railing designed
to withstand vehicular crashes on bridges is greater than the cost of a railing designed for
pedestrian and bicyclist loading. Therefore, separate cost comparisons were conducted
for bridge railing and shared use path railing. The primary source of cost information for
the cost comparison was the 2004 RSMeans “Heavy Construction Data,” which provides
national averaged unit prices for various construction materials. The unit prices include
the costs of material, labor, overhead, and profit.
The source of cost information for bridge railings was the New York State Average
Weighted bid prices. These prices can vary greatly from one state to the next depending
on labor and material costs, and the design of the state’s standard bridge railing systems.
New York has developed a system of similar standard bridge railings that vary in size,
height, and number of rails depending on the intended use. Two- and three-rail systems
are used for bridges that accommodate only vehicular traffic. Four-rail (42-inch high)
systems are used for bridges that accommodate pedestrian traffic. Five-rail (56-inch
high) systems are used on bridges that require added protection for bicyclists. The use of
a similar rail system with multiple rails allows for an easy cost comparison. Although the
bid prices are unique to New York, the relative costs are useful in illustrating the cost
effect of adding an additional rail.
In addition to the cost difference between a 1.1-meter (42-inch) and a 1.4-meter (54-inch)
railing height, the cost of railing compared with the rest of the facilities was also
investigated.
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