Sonoma County has many miles of beautiful tree-lined
rural roads. Most are quite narrow, with minimal or no paved shoulders
and deep ditches close by.
Widening is seldom feasible. The County doesn't even have enough
money to maintain them adequately. Even if money were not an obstacle,
there would be resident opposition to widening because of expected
increases in traffic volumes and speeds, as well as loss of the
trees that line the roadways. Many residents don't even want potholes
filled, preferring to take the bumps themselves than to encourage
other drivers to drive fast.
While these roads are not inherently dangerous, they become so
due to the often excessive vehicle speeds. Even the posted speeds
are well beyond prudence. With the application of the 85th percentile
rule, posted limits have been ratcheted up over the years as people
have chosen to go ever faster, and the signs have been changed
to reflect what people do.
But leaving roads to deteriorate is a poor option. Once they
degrade to a critical point they must be rebuilt at great expense.
In the long run, roads cost less if properly constructed and then
The engineers understand this all too well, and one would expect
them to want to do the job right if given the funds to do it.
However, many of them believe that "doing it right"
includes bringing the roads up to more modern geometric standards
- widening lanes and shoulders, gentling the curves, lengthening
sight lines. It is this part of the "standards" that
brings them into conflict with the people that live nearby, because
it results in higher speeds and loss of trees. To defend their
choice, the engineers frequently fall back on the "necessity"
of conforming to certain standards in order to obtain federal
or state funds, or to avoid lawsuits over safety deficiencies.
Yet recent studies have demonstrated that extra efforts to accommodate
errant drivers have had negative effects on safety overall.
Faced with this reluctance of engineers to offer high construction
quality while retaining historic geometrics, how can this conflict
be resolved? There is a growing body of thought that those same
geometrics look a lot like emerging practices of traffic calming.
And the pioneering steps have already been taken to provide greater
flexibility in design standards. Vermont, a state only 35% larger
in population than Sonoma County, has many similarities: ruralism,
beautiful rolling countryside, sprawl endangered, and narrow rural
roads. It has established standards for local streets and roads
that make use of the new flexibility in Federal Highway Administration
With this as background, the SCTLC is proposing a System of Heritage
Roads for Sonoma County. The concept is to maintain designated
low volume rural roads in their historical configurations. The
designation would be applied for by the local residents. In the
application, they would accept certain (yet to be defined) speed
standards, and fair sharing of the facilities by motorists, cyclists,
pedestrians and other legitimate users of the road. In return,
as funds become available, their Heritage Road would be improved
without significantly changing geometrics, and user requirements
would be enforced.
Although the source of funds to do this is currently unknown,
it seems reasonable that a Countywide funding package would include
a provision for Heritage Roads in the rural areas to balance off
the transit and non-motorized facilities it would provide in urban
The Vermont road standards are available at VTrans, the
website of Vermont's Agency
of Transportation. (Scroll down to 6.0 Local Roads and
Clallam County, Washington has similar problems with its
rural roads. Its Commissioners (supervisors) In 1999 its
County Commissioners appointed citizen members to the Clallam
County Rural Roads Design Standards Advisory Committee and
charged it with two tasks:
Task 1. Formulate recommendations for appropriate levels
of community involvement during road project development.
Task 2. Formulate recommendations for design standards
used in road construction and reconstruction in rura lroad
construction and reconstruction in rural areas.
The reports that came from the citizen effort could be
a model for how to proceed in Sonoma County. They are available
at the Safe Rural
An excellent paper relating lane widths to safety was "Accident
Relationships of Roadway Width on Low-Volume Roads"
by Zegeer, Stewart, Council and Neuman.
Download Zegeer et al PDF file.