PO Box 1066
Tel: 707 937-3001
Mendocino, CA 95460
September 6, 2005
California Coastal Commission
Att.: Melanie Faust
710 E Street, Suite 200
Eureka, California 95501
Re.: Coastal permit application for the
replacement of the Greenwood Bridge, Mendocino County, # 1-05-036 and
The proposal by Caltrans to construct the
replacement for the Greenwood Bridge with 1) no sidewalk, 2), the ST-20
railing 3) and 8' shoulders should be amended.
The Commission should:
Require that a sidewalk be installed on the bridge;
Require that pedestrians be protected from the traffic by
placing the ST-10 railing used on the Noyo Bridge on the traffic side of
Require use of a newly designed pedestrian railing incorporating
curved and arched elements found in the historic bridges of Hwy 1, as
officially recommended by the Commission to Caltrans in 2001; and
Require that the shoulder width be narrowed from 8' to 4'.
Reasons and Documentation
Why a sidewalk?
The lack of
sidewalks goes against the commission's support for the California coastal
trail. This bridge will be part of coastal trail and should provide for
safe pedestrian use.
The Greenwood Bridge is near the town of Elk and is used by local
citizens. Lack of a sidewalk endangers pedestrians.
Why a two-rail system with the ST-10?
safety standards (the "AASHTO" standards) subscribed to by California say
that pedestrians on bridges shall be protected from vehicles when the
highway is designed for high speeds (50 MPH or greater). This protection
requires a traffic barrier on the traffic side of the sidewalk.
The Greenwood bridge, with its 11-degree banking slope, is designed for
vehicle transit greater than 50 MPH.
Because the bridge will be occupied by pedestrians, the proposed
use of a combination vehicle-pedestrian-bicycle rail, the ST-20, on the
Greenwood Bridge is contrary to AASHTO standards. The AASHTO standards
limit use of a combination vehicle-pedestrian rail placed on the outer
edge of a bridge, "to roads designated for 45 MPH or less."
Another ASHTO document says, "For speeds of 50 MPH or greater, pedestrians
should be protected by a separation traffic barrier."
The AASHTO standards for pedestrian protection can be met by using
the two-rail system so successfully employed on the new Noyo Bridge. The
inner rail is an ST-10, which has a low height and good visual
The use of an inner rail, together with a 4' shoulder to be used by
bicycles, will allow the outer rail to be a pedestrian railing. This will
greatly improve scenic viewing and bridge aesthetics.
Why a newly designed railing?
new pedestrian railing needs to be designed for coastal bridges. The
ST‑20 railing proposed by Caltrans fails to embody the recommendations the
Commission made to Caltrans in June, 2001.
The ST-20 railing is 54" high, creating visual obstructions for
cyclists and pedestrians, without protecting them from traffic. The
railing lacks any architectural merit.
The ST-20 railing need not and should not be used on any bridges
in the coastal zone.
The 2001 recommendations of the commission to Caltrans were based on the work and
advice of the commission's "Railing Subcommittee," established in December
1999. The subcommittee met numerous times with Caltrans and received
advice from the public. Two of the key commission recommendations were:
Curved and arched
elements should be explored, in order to make the rail design as graceful
and attractive as possible.
Because of the loss of many historic and attractive
bridges throughout California, a new rail design should seek to
incorporate elements of historic bridges where consistent with modern
railing could easily incorporate curved arches that would reflect the
arches that were incorporated into railings of the historic arched,
concrete bridges of Highway 1.
The arched railings would provide a link
to the historic past. They would provide a feeling of tradition, as well
as aesthetic beauty. Examples of such railings are shown below.
These railing are on bridges in France and are of
cast iron. Alternative materials could be used, although cast iron would
be structurally adequate for pedestrian railings.
The original Hwy 1 bridges have arched designs and arches in the railings,
as shown in the photos below of the Russian Gulch Bridge in Mendocino.
Why narrow the shoulder width?
The 8' shoulders proposed for the bridge are contrary to the
Coastal Zone Act of 1976, which requires that “…Route 1 in
the rural areas of the Coastal Zone remain a scenic two lane road.”
shoulders would make the bridge width exceed the maximum highway width
specified in the Coastal Act and the Local Coastal Plan of Mendocino
Caltrans Route Concept Report Route 1 Corridor in Mendocino
County states: "Widening Route 1 to beyond 9.6
meters (32’), in rural
areas would be inconsistent with the Coastal Act and the Local Coastal
Plan of Mendocino County."
The bridge as proposed would be 40'.
Reducing the shoulders to 4' would put the bridge at the width limit of
the Coastal Act and the Mendocino Local Coastal Plan.
Narrowing the shoulder would provide room for a sidewalk without
widening the bridge beyond the proposed width. The sidewalk with an inner
barrier would provide safe pedestrian use.
A narrower shoulder would help slow down traffic on its approach to
the village of Elk, a rural community that has Hwy 1 as its only main
The proposed shoulders would be 60 percent as wide as the traffic
lanes. They would make the bridge more like a high-speed expressway than a
"scenic two lane road."
A narrower shoulder would still be wide enough to provide safe
bridge transit for bicyclists.
A narrower shoulder would better match the almost non-existent
shoulders on most of Hwy 1.
Eight-foot shoulders are suited to high-speed urban roads. They are
completely inappropriate for rural sections of historic Hwy 1. They are
out of character with the Hwy 1's rural, scenic character.
The widening of the shoulders for the bridge approach contradicts
another Caltrans policy: avoiding variations in highway width – a policy
cited by Caltrans in justifying 8' shoulders on the Noyo Bridge.
Eight-foot shoulders on the bridge would be inconsistent with the
remainder of Hwy1. Hwy 1 has almost non-existent shoulders throughout most
of Mendocino County. The shoulders will be as wide as they are on the
bridge approach only because Caltrans plans to widen the approaches for
this small section.
Given the overall dangers of driving on Hwy 1, the incremental
improvement in safety from a few hundred feet of 8' rather than 4'
shoulders would be insignificant.
Why ignore Caltrans safety arguments?
Caltrans will argue that 8' shoulders are its design standard, based on
safety considerations. The commission should not accept this argument.
- There are no
"absolute safety standards" that must be met, regardless of other
National and state design standards give Caltrans wide latitude to
accommodate special situations. Preserving scenic values is widely
recognized as an important reason to use this flexibility. In passing
the Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991,
Congress emphasized, in addition to safety, the importance of
transportation design that is
to its surrounding environment, especially in historic and scenic areas.
Caltrans has total authority to make exceptions to any of its design
standards when the project is not part of the interstate highway system.
Caltrans recognizes that design standards will not always be met. It
devotes an entire chapter of its Project Development Procedures Manual
to exceptions, and a section to "Exceptions to Mandatory Design
Obtaining an exception on a project is straightforward. The reasons for
exceptions must be documented, and the request must be approved by the
Project Manager and the Design and Local Programs Program (DLPP) office.
The DLLP authority has been delegated to local district coordinators, who
provide the highest level of approval for design exceptions.
Caltrans has made an exception to its current design standard of
8' bridge shoulders on at least one other project. Highway 150 in
District 5 had two bridges replaced recently. The bridges were designed
originally with 8' shoulders, but after Santa Barbara agencies opposed the
width, Caltrans narrowed the shoulder width on these bridges to 4'. These
bridges have now been built (on an emergency basis) with the narrower
Caltrans has recently changed its standards with respect to
bridge railing design, demonstrating its flexibility in design standards.
When the Commission was considering the Noyo Bridge railing, Caltrans
design standards required less than 4" spacing between rails less than 32"
from the surface. In response to public desires for more visually
transparent railings, Caltrans has changed the required spacing to less
The ST‑20 railing has the new 6" spacing.
There are no national design standards that mandate 8' shoulders
To the contrary, the AASHTO design standards specify, "The roadway width
[of a bridge] shall generally equal the width of the approach roadway
section including shoulders."
Note that this is not a rigid requirement and only a "general" guideline.
For a structure somewhat like a bridge, a highway underpass, AASHTO
standards require only minimum 2' shoulders.
national standards when it suits its purposes. The approach to the
proposed Greenwood Bridge will have one 8' shoulder (on the
east side) and a 4' shoulder on the west side. AASHTO design standards
specify, "The roadway width [of a bridge] shall generally equal the
width of the approach roadway section including shoulders." However, on
the west side, the width of the bridge shoulder will be twice that of
the approach shoulder.
A safety argument is not supported by Caltrans shoulder treatment
in other, far more dangerous situations. Numerous 8+-lane freeway segments
do not have an inner shoulder. I recall when Caltrans converted the inner
shoulder to a traffic lane on congested high-speed L.A. freeways.
The Greenwood Bridge
will set a precedent for future bridges to be constructed by Caltrans on
The commission should set standards that reflect
previously expressed commission concerns and recommendations. The
Require a sidewalk to protect pedestrians and further the
Require use of a two-rail system to protect pedestrians
and to provide for optimal railing aesthetics and motorist views.
Require use of a newly designed scenic pedestrian rail
acceptable to the commission. The two-rail system with an outer pedestrian
rail will provide wide latitude for designing a rail incorporating curves,
arches, and historical elements.
Vince Taylor, Ph.D