Klayton Eckles
|
October 14, 2002 |
I have reviewed the Draft guidelines and find issue with one aspect. In the
section pertaining to crosswalk design the following language is included:
The cross slope is limited to 1:48, except at mid-block crossings. The cross
slope of the crosswalk is the running grade of the roadway. It is not uncommon
for streets to be constructed with constant profile grades up to 9 or 10
percent. This specification would require reduction of these profile grades to 2
percent at intersection crosswalks, thus forming "tabled areas" at intersections
so that the 1:48 slope is achieved at crosswalks. The specified running slope
for crosswalks is 1:20. Such design requirements are not practical or
appropriate. Constructing "tabled areas" at intersections would create the
following undesirable results:
1) Defacto speed bumps would jostle drivers and emergency vehicles causing a
hazardous discontinuity in the roadway.
2) Intersection design and sight development would be driven by Cross walk
design, rather than the existing topography, yielding greater disruption of the
environment.
3) Drainage would be impaired. Intersections already have too much happening in
them, and water flow is always a challenge. "Tables" would introduce a major
impediment to water flow and storm sewer design and installation.
4) Tables would be difficult to plow, and would tend to trap snow and ice right
at the intersection (not a good place for ice). Also plows would damage the
Tables.
Improving the grade on crosswalks is a laudable objective. Unfortunately it
introduces too many challenges into the design of intersections, streets, and
developments. New and good development recognizes the topography and environment
that exists. Adding this crosswalk requirement would have the tail wagging the
dog. First we need to design safe roads and quality developments. I recommend
the same language be used for sidewalk design along roadways, i.e. cross grades
on cross walks may be that of the street.
Thank you for considering my comments,
Klayton Eckles
Director of Public Works
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