There are no “significant” traffic
impacts caused by the glut of new high-density housing planned
and already
approved in downtown Walnut
Creek.
And the City Council has the numbers to prove
it. Of course, the way
the Council has
decided to quantify
traffic impacts
has a lot to do with this conclusion.
For most downtown
intersections,
traffic congestion is rated on a Level of Service (LOS) basis. The LOS ranks, on a scale
of A to F, how long
it takes traffic to get across an intersection.
If you sail right through, or are only delayed for a
short time waiting
for the signal light to change, that’s LOS A.
If the traffic light cycles are really long, and you’re
sitting through
multiple cycles before you can get through, that’s LOS F. LOS is analyzed for travel
in all directions and
all turns through an intersection.
When
traffic from a new project is projected to degrade service -
especially by a
letter grade – like from LOS D to E, or from LOS E to F,
mitigation measures
are required.
Level of Service
used to be the
City-wide standard, but a number of intersections downtown,
especially along Ygnacio
Valley Road
were operating near critical levels. So,
the City Council changed the rules. The
Council identified Ygnacio
Valley Road as a “Route of
Regional Significance” and
declared that Level of Service no longer applies. It would be more
appropriate, they said, to analyze
traffic impacts on Ygnacio using the same criterion that applies
to Highways 24
and 680.
Traffic impacts on
freeways are
measured by a “Delay Index”. The
concept
is pretty simple … you compare how long it takes to drive from
POINT A to POINT
B during commute hours with the time it takes when there is no
traffic at
all. If the commute
drive time is more
than double the non-commute drive time, you have a “significant”
impact that
needs to be addressed.
At first blush,
this approach
doesn’t sound unreasonable. But
Ygnacio Valley Road
isn’t a freeway. Freeways
have no cross
traffic or stop lights.
The Delay Index
ONLY measures how
long the east-west commute along Ygnacio takes – not how long it
takes to CROSS
Ygnacio if you happen to be traveling north-south on an
intersecting street, or
if you need to make a left turn.
Furthermore, there
is really no such
thing as an “uncongested” travel time on Ygnacio. Even if you’re not stuck in
traffic, you will
be stuck waiting through the notoriously long light cycles. If the delay is the same,
whether caused by
traffic lights or actual traffic, the Delay Index calculates out
to an “excellent”
1.0.
The selection of
“Point A” and
“Point B” has a major effect on the calculation too. Unlike the LOS standard,
which is measured at
each individual intersection, the City has elected to ONLY
calculate the Delay
Index for the entire trip between Oak Grove Road and the
Freeway. Even if a
development, like the BART Transit
Village,
is likely to jam
up one or two particular downtown intersections, the effect on
the Delay Index
calculation is diluted by factoring in the part of this lengthy
route that
isn’t affected.
I’m not the only
one who thinks
this methodology is flawed. The
State
Department of Transportation has also taken issue with the
City’s approach to
evaluating traffic impacts on Ygnacio.
In comments to the Environmental Impact Reports of
recently proposed
projects, CALTRANS has stated that the Delay Index calculations
are
insufficient to gauge traffic impacts at the intersections with
freeway on and
off ramps.
So why would the
City Council
adopt Delay Index as the standard for analyzing traffic impacts? My answer is that the
business and development
interests, who help put the Council members in office, don’t
want to allow
environmental concerns to stand in the way of major (and very
profitable)
projects like the BART Transit Village or 1500 No. California Boulevard. I’d be happy to hear if
anyone out there in
the Ygnacio
Valley
can come up with a less sinister explanation. Think about it when you’re
stuck in traffic.
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