Ten Mile Bridge Opens
On Friday, May 8, 2009, at 1:00 p.m. the
official opening of the new
Ten Mile Bridge was celebrated.
The final result can justly be celebrated as a symbol of what
community action, the Coastal Commission, and Caltrans working together can
The initially proposed bridge would have been much larger
and uglier and done unnecessary damage to rare environmental and scenic
As a result of community opposition to the initial design,
Caltrans worked with the community and the Coastal Commission to come up
with a design that was smaller, better aligned, incorporated a
pedestrian walkway, and a newly designed railing that preserved scenic views
and is aesthetically pleasing. It revised its plans and construction methods
to protect the wildlife and fish of this amazing sanctuary. During the
opening ceremony, a deer passed below in back of a speaker. An osprey flew
up right over the bridge, evidently to see what was happening. Many birds
and a seal were in the water below.
|Looking up 10 Mile Estuary through
new combo rail
At the opening ceremony, all of the Caltrans staff that
worked on the project acknowledged the value of the review by the Coastal
Commission and the critiques provided my the local community. They all felt
that the bridge was better because of, even though their tasks were made
District Director Charlie Fielder was generous in
his praise for my contributions to gaining a better railing design.
The final design was due to the combined efforts of me, the Coastal
Commission Committee on Bridge Railings, and Roberto LaCalle of Caltrans.
All are happy with the final result.
Ten Mile Bridge Nears Completion
March 26, 2009. I paid a visit to the site of the new Ten
Mile Bridge, which is nearing completion. The new combination
bicycle-automobile railing is now in place, though not painted. It looks
splendid in this beautiful setting.
A closer look reveals a design flaw that
could represent a hazard to bicyclists:
The upper part of the railing is set back
from the automobile crash barrier, creating a gap between the two that is
potentially hazardous to cyclists.
I urged at the time that this gap be eliminated, but Caltrans objected
on time-issues and motorist safety concerns, and the Coastal Commission
Because the combo railing is visually
attractive, it is likely to be used on other scenic bridges, including the
upcoming rebuild of the Greenwood Bridge in Elk. Now is the time for
Caltrans to do the redesign and testing necessary to create an integrated
New Design for Ten Mile Bridge Railing
September 9, 2007, Eureka. Working together with the Railing
Subcommittee of the Coastal Commission, Caltrans developed a much improved
railing design for the new Ten Mile Bridge.
A key to the improved design was the decision by Caltrans
to accept a 42-inch height for the bicycle railing (as compared to the
previously required height of 54"). This height conforms to the height
adopted by AASHTO, the national highway standards organization in May, 2006.
Caltrans was initially opposed to accepting the 42"
provided Caltrans and Coastal Commissioners with data and argument in
support of this standard. Caltrans determined that it would need to do
its own internal review of the appropriate height.
The decision to use a 42-inch railing allowed the east
railing, which needed to protect for both cars and bicyclists, to be based
on the visually transparent and pleasing ST-10, with the addition of a
smaller top railing at 42". At the request of the Bridge Railing
Subcommittee, curved elements were placed between under the top railing down
to the height of the second structural member of the ST-10. The result can
be seen in the "elevation view" in the photo above.
What isn't apparent in these views is that the top railing
is set back 15" from the front of the ST-10. This creates a 7" gap between
the back of the ST-10 rail and the bicycle railing.
I argued, unsuccessfully, that this created a safety hazard for cyclists and
that the gap should be eliminated. Caltrans stated that it would be too
time consuming and expensive to develop a design without the gap. The
Commission staff supported the Caltrans design (see
The Coastal Commission approved the proposed Caltrans
railing on September 9, 2007. Although there are some concerns about the
approved railing with respect to cyclist safety, these concerns are
relatively minor compared to the huge improvement in aesthetics and
transparency compared to
initially proposed design.
The Ten Mile Bridge is scheduled for completion in 2009.
More on the history of
Ten Mile Bridge project
Ten Mile Bridge
Good and not-so-good news
June 10, 2006, Santa
Rosa. The Coastal Commission approved without discussion a revised
Caltrans proposal for the Ten Mile Bridge. The revised design has a single
five-foot sidewalk on the west side, six-feet shoulders on both sides, and
a combination auto-bicycle railing on the east side.
The revised design was
Caltrans' response to the Commission's November, 2005, specification of
four-foot shoulders and sidewalks on each side of the bridge. From the
standpoint of preserving the scenic values of Ten Mile River, the revised
design is mixed. On the positive side, the single five-foot sidewalk
reduces the scale of the bridge as compared to two four-foot sidewalks.
The six foot shoulders are unnecessarily wide from an automobile safety
standpoint, but five-foot shoulders are recommended for bicycle safety;
thus the arguably unjustified width of the bridge is only two feet.
In a welcome move,
Caltrans and the Commission agreed to defer for a year choosing a design
for the railings on the bridge. The design of the railing for the east
side of the bridge is challenging, because it will need to protect
bicyclists as well as cars. The initial design proposed by Caltrans was a
visual catastrophe – suitable for a cattle gate, but not a scenic bridge.
Caltrans and a subcommittee of the Commission have been working on
developing alternative designs. I was invited to assist the subcommittee
and have been doing so. To date, no really attractive designs have been
developed, but Caltrans seems open to meeting the concerns of the
Commission and the public.
[Just this week, (June 27, 2006) I received extremely good
news that creates a much greater probability of making a visually
attractive and transparent design for the east railing: the national
highway standards organization followed by Caltrans has just lowered the
bicycle railing height from 54" to 42" (the same as pedestrian railings).
This will improve enormously the aesthetic possibilities for railing
The most discouraging
aspect of the Ten Mile decision was the Commission's acceptance of bogus
"safety data" from Caltrans. The Commission staff and ultimately the
Commission accepted the wider shoulders because Caltrans asserted that
moving from four to six foot shoulders would reduce accidents by 44
I was not provided the
source of the Caltrans safety estimate until after the Commission staff
had published its staff report, too late to provide correct information to
the staff and too late even to get written comments to the Commissioners
until the night before the hearing. It is doubtful that any Commissioners
even reviewed my
written testimony (free
Adobe Acrobat Reader, if needed). Although at the hearing, I that
showed that there was no empirical basis for Caltrans' safety assertion
and that there was no significant vehicle safety benefit from the wider
shoulders, it was too little too late.
On the positive side,
Caltrans has invited me to work with me on future bridge designs prior to
submitting permit applications to Caltrans. I've accepted the invitation
and hope to come to resolve our differences around safety arguments. The
evidence on shoulder width and safety is very clear. I am optimistic,
therefore, that future coastal bridges will be built with the five-foot
shoulders that are needed to for cyclist safety and no wider.
All in all, progress
is being made, largely because of the outpouring of public support for
bridge designs that protect the scenic values of our beautiful North
Thank you for your
help and support.
June 10, 2006, Santa
Rosa. The Coastal Commission approved without discussion a revised Caltrans
proposal for the Ten Mile Bridge. The revised design has a single five-foot
sidewalk on the west side, six-feet shoulders on both sides, and a
combination auto-bicycle railing on the east side.
revised design was Caltrans' response to the Commission's November, 2005,
specification of four-foot shoulders and sidewalks on each side of the
bridge. From the standpoint of preserving the scenic values of Ten Mile
River, the Commission's latest action is mixed. Overall, though, progress is
Other Ten-Mile news.
Bicycle Railing Height Standard Reduced
May 2006. Perhaps the most important action for preserving
vistas was taken recently by the national highway standards organization
At its May, 2006 meeting, the bridge committee lowered the
railing height for bicycle railings from 54" to 42", the same height as
pedestrian railings. This change will improve enormously the aesthetic
possibilities for railing designs. This is important for Ten Mile Bridge and
all other bridges on Highway 1 where combination auto-bicycle railings are