[Carfreeliving] Driveway curb cuts decrease ped/bike safety; cities should prohibit them or apply impact fees to capture full social costs

Wed Apr 27 16:03:03 MDT 2005

actually, I think the real reason why curb cuts/garage access should be
banned on certain streets has nothing to do with safety, and I think that
this safety argument is not going to be what convinces people to accept
curb cut bans (which means some properties will be prevented from having
parking). While driveways are a safety issue, there haven't been a rash of
driveway deaths in SF because this isn't a suburban area where driveways
are huge swaths of pavement where little children are likely to be playing
and crawling around.

In mind, and from my experience as an SF planner talking to residents in
areas of the city generally opposed to lower parking requirements, the
reason that really resonates with them to accept a curb cut ban, and there
for some car-free housing, is the protection of ground floor commercial
space on neighborhood commercial streets. People really cherish their
walkable neighborhood commercial districts, with mom and pop shops and
continuous storefronts. They recognize that requiring, or even allowing,
curb cuts means essentially the obliteration of neighborhood commercial
streets and replacing it with a garagescape. The typical San Francisco lot
is 25' wide, and on most street lots are not wider than 40' or 50'. This is
not enough space for garage doors and ground floor retail to exist
together. It's generally one or the other. Even if there are larger parcels
that could accommodate both to a certain extent, people seem to recognize
the desire to not have garage doors and cars crossing sidewalks in the
middle of an active pedestrian sidewalk.

Chicago is actually instituting a curb cut ban for this reason, for
pedestrian-oriented neighborhood commercial preservation.

Fortunately, most of the our neighborhood commercial corridors are also
transit streets, and many are also bike streets, so you don't even have to
argue that the transit and bike angle. The reduction in public parking and
the safety reasons are real and I support, but they don't really seem to be
convincing many people who are insistent that, in concept, every dwelling
unit must have an off-street parking space.

-josh

                      "Jeremy Nelson"                                                                                                  
                      <jeremy at livablecity.org>          To:       <Carfreeliving at livablecity.org>                                      
                      Sent by:                          cc:       debby.schaaf at phila.gov                                               
                      Carfreeliving-bounces at liva        Subject:  [Carfreeliving] Driveway curb cuts decrease ped/bike safety;         
                      blecity.org                        cities should prohibit them or apply impact fees to      capture full social  
                                                         costs                                                                         

                      04/27/2005 01:09 PM                                                                                              
                      Please respond to jeremy                                                                                         

Deborah Schaaf wrote:

"We are starting to grapple with the possibility of limiting front garages
and driveways for new residential development.  I'm talking about rowhouses
or twin houses here, not single-family detached.  Often the most compelling
argument against driveways is that they convert public parking spaces into
private ones.  However, I also want to make the argument that having too
many driveways diminishes the pedestrian quality of the sidewalk.  I seem
to
remember hearing somewhere that a significant share of child pedestrian
injuries occur in driveways.  Can anyone confirm this?"

Jeremy Nelson writes:

"Driveway deaths may seem to be rare accidents, but they are not:  a fifth
of children killed as pedestrians by motor vehicles perish in driveways in
the US.  [...] Until recently, the evidence for a special problem with SUVs
in driveways was largely anecdotal [...].  The first good study of this
issue was recently performed in Australia, and lumped together four-wheel
drive vehicles with light commercial vehicles.  The study found that these
vehicles made up 30.4% of the registered vehicles in southeastern Australia
but accounted for nearly two-thirds of the children killed in driveway
accidents.  Almost all the deaths occurred when these vehicles knocked down
a child and then crushed the child's head with a tire."

- Source:  Keith Bradsher, "Trouble for Cities" in _High and Mighty: The
Dangerous Rise of the SUV_, pp 233-234.  Original source:  Andrew J.A.
Holland, et al, "Driveway Motor Vehicle Injuries in Children," _Medical
Journal of Australia_, vol 173, pp 192-195.

For these reasons, and the other good reasons discussed in earlier posts,
cities should be developing urban design guidelines that minimize and/or
forbid driveway curb cuts on major transit, bicycle, and pedestrian
streets.
In those places where cities choose to allow driveway curb cuts, the city
should require applicants to pay an "impact mitigation fee" that covers the
full social costs of driveway curb cuts.  These costs include:

1) The market value of the curb parking space that a driveway curb cut
eliminates from the public right-of-way.

2) The market value of the "driveway easement" that is essentially being
granted for a driveway curb cut for the right of driving a private
automobile across the sidewalk (after all, this is the pedestrian
right-of-way).

3) The increased public health and public safety costs of the increased
risk
to pedestrian and bicyclist safety caused by vehicles backing out of
driveways.

4) The increased enforcement costs of keeping the pedestrian right-of-way
clear of parked cars (a driveway/curb cut is an invitation to park on the
sidewalk, and I've found that a significant number of drivers simply can't
refuse this invitation).

5) The cumulative opportunity costs of lost tree planting sites on the
sidewalk (both in the driveway area and adjacent to the driveway, as street
trees have to be set back at least 3 feet from the curb cut line just to
keep them safely out of reach from vehicles turning into and out of the
driveway).

6) Since street trees remove CO2 and soften street noise for residents,
fewer street trees leads to higher air and noise pollution mitigation
costs,
so cities should quantify and recoups these costs as well).

7) Finally, the fee should include some additional amount to compensate the
neighborhood/city/region for the degradation of the public realm caused by
a
garage facades that deaden the pedestrian realm (removes visual interest,
creates crime hot spots, etc). Most developers and real estate brokers know
that aesthetic value can be monetized, and that this quantifiable value can
be legally defended in court.  Unfortunately, cities are leaving money on
the table if they don't recapture the reduced value of the public
right-of-way caused by street-fronting garages and the driveways and
accompanying curb cuts that feed these garages.

I wish San Francisco's Planning Department would expand to the entire city
their recent good work of banning curb cuts on major transit, bicycle, and
pedestrian streets in new area plans (Rincon Hill, Mid-Market, etc.).

Next, Planning should do a nexus study to calculate the total social costs
to mitigate the impacts caused by driveway curb cuts and, wherever driveway
curb cuts are still allowed, assess the full "driveway curb cut impact
mitigation fee" (DCCIMF?) for all applications.

My guess is that if the fee actually covered the full social costs, it
would
be so high that curb cuts would be cost prohibitive for most applicants.
Transportation for a Livable City would support such an effort by the
Planning Department, and my guess is that other advocacy groups would as
well.

If there are any city planners on this list, please advise how advocacy
groups can best support your efforts to pursue these ideas.  Perhaps it
makes sense for advocacy groups to meet with one or more Supervisors to
educate them on this issue and see if anyone is interested in introducing
legislation to forbid curb cuts on transit/ped/bike streets (the
prohibition
approach) and then request a nexus study to apply a market-rate impact
mitigation fee on the rest of our city streets (the pricing approach).

Best - Jeremy

===================================

Jeremy Nelson
Policy Director
Transportation for a Livable City (TLC)
NOTE NEW ADDRESS & OFFICE PHONE:
995 Market St., Suite 1550
San Francisco, CA 94103
office: 415.344.0489
cell: 415.425.9848
fax: 775.540.9813
e-mail: jeremy at livablecity.org
web: www.livablecity.org

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