Comment Log Display

ARB staff,

On page 38 of the Proposed Scoping Plan (Oct. 2008) the following
is stated: "Passenger vehicles are responsible for almost 30
percent of California’s greenhouse gas emissions. To address these
emissions, ARB is proposing a comprehensive threeprong strategy –
reducing greenhouse gas emissions from vehicles, reducing the
carbon content of the fuel these vehicles burn, and reducing the
miles these vehicles travel."

I propose a fourth prong to the approach: improved urban
transportation efficiency.  

I have a specific idea in mind that would: 1) reduce idling
emissions, 2) overall travel time on urban streets, 3)vehicle
acceleration emissions (which produce substantial CO2 - especially
heavy trucks).  My proposal involves replacing stop lights and/or
stop signs with modern roundabouts because they are far more
efficient.

As documented in the transportation literature, modern roundabouts
move cars through an intersection about 30% to 50% more efficiently
than a signal or stop sign during peak hours.  There are about
250,000 stop lights in the USA (DOT 2006) and, based on population,
I estimate about 10% of these are in California - or roughly 25,000
stop light controlled intersections.  I have conducted research on
CO2 reductions possible from stop lights being replaced with a
modern roundabout.  The estimates for efficiency vary with local
conditions (e.g., traffic volume, number of intersecting streets). 
As a general rule, the annual reductions in CO2 range from about
300 tons/year to over 3,300 tons/year.

What type of GHG emission reductions are available for California?
 Assuming CO2 reductions at the low end - perhaps 500 tons/year,
and roughly 1/2 of California stoplights amenable for conversion to
a modern roundabout, then a conversion measure could yield a
permanent reduction of about 6 million tonnes CO2.

There are other benefits from signal conversion that could accrue
as well, because roundabouts reduce injury accidents by about 60%,
they work when the power fails, and they can be used for community
beautification with landscaping and sculptures (e.g. Bend, Oregon).
 There would also be tremendous time saving for delivery vehicles
and other travelers at peak hour.  For instance, the average
peak-hour delay at a roundabout is seven seconds, vs a minute or
more at a stop light.  Do the math on idle emissions!

I have a attached a zip file with several example documents for
your use.  Please consider adding improved urban transportation
efficiency to the PSP as a fourth prong.  This is a simple, cheap,
and proven way to reduce GHG emissions from the transportation
sector.

respectfully,

David Morrow AICP

ps: France is building about 1,000 roundabouts annually primarily
to increase safety.  We are a bit behind but can catch up.