TRAFFIC CALMING
Introduction
The City of San Fernando is trying new methods to deal with the
issues of increased vehicular traffic. In an effort to be more
responsive to the needs of the community, over the past two
years, the City Council committed resources to develop a Citywide
Traffic Calming Plan. The Public Works Department, along with
guidance from the Transportation and Safety Committee, developed
a comprehensive Traffic Calming Study and Master Plan. These
two documents lay the ground work for applying traffic calming
methods in a consistent manner Citywide. Staff is confident
that the community will be satisfied with the results.
Two maps are available which summarize the City’s Traffic
Calming Master Plan, the approved traffic calming tools, and
the Phase I traffic calming improvements. The Traffic Calming
Master Plan was developed based on extensive community outreach
and the recommendation of proven methods for calming traffic.
In March 2004, the City will begin the installation of its first
ever Speed Humps and Speed Tables at various locations which
are shown on the Phase I traffic calming improvements map.
What are Speed Humps?
Speed Humps are asphalt mounds placed on roadways for the purpose
of slowing traffic. Speed humps are different than speed
bumps, which are commonly seen in parking lots or on private
streets.
Speed Humps span the full width of the street, typically
36 to 40 feet. The City of San Fernando speed hump standard
is
12 feet
measured longitudinally and three inches high. Speed Humps
are typically placed 300 to 600 feet apart and are installed
on residential
streets experiencing speeding problems.
What are Speed Tables?
Speed Tables are longer and sometimes appear, to be more
flat on the surface, speed humps are used primarily for
the purpose
of slowing traffic. Speed Tables are more gently sloped
than Speed Humps, provide slightly higher design speeds
than Speed
Humps, and are used at locations where low speeds are
desired but a somewhat smooth ride is needed for larger vehicles
since they long enough for the entire wheelbase of a
passenger
car
to rest on the top section.
Speed Tables span the full width of the street, typically
36 to 40 feet. The City of San Fernando speed table
standard is
22 feet measured longitudinally and three inches high.
Speed Humps are typically placed 300 to 600 feet apart
and are
installed on residential collector streets experiencing
speeding problems.
Why are Speed Humps/Tables desirable?
Speed Humps/Speed Tables can help control speeding
on local neighborhood streets: They can reduce average
speeds
by
as much as seven mph.
Unlike traditional police enforcement, Speed Humps
provide continuous service. They may also help discourage
cut-through
traffic by
diverting it elsewhere.
Applications:
- Residential streets
- Not typically used on major roads,
bus routes, or primary emergency response routes
- Mid-block
placement, not at an intersection
- Not on grades greater
than eight percent
- Work well with curb extensions
Design/Installation Issues:
- Typically 12 to 14 feet in length;
other lengths (10, 22, and 30 feet) reported in practice
in U.S.
- Speed hump shapes include parabolic,
circular, and sinusoidal
- Hump heights
range between three and four inches with trend toward
3 - 3 ½ inches
maximum
- Difficult to construct
precisely; may need to specify
a construction
tolerance
(e.g. ± 1/8
inch) on height
- Often have signage
(advance warning sign before first
hump in series
and warning
sign or object
marker at
hump)
- Typically have pavement
marking (zigzag, shark's tooth, chevron,
zebra)
- Taper edge near curb
to allow gap for drainage
- Some have speed advisories
- Bicyclists prefer that it
not cover or cross a bike
lane
Potential Impacts:
- No effect on non-emergency
access
- Speeds determined
by height and spacing; speeds between
humps have
been observed
to be reduced
between 20 and
25 percent
on average
- Most communities
limit height to 3-3½ inches,
partly because of harsh
ride over 4-inch high
humps
- Possible increase in traffic noise from braking
and acceleration
of
vehicles, particularly
buses
and trucks
Emergency Response Issues:
- Concern over jarring
of emergency rescue
vehicles
- Approximate delay of between three and
five seconds per
hump for fire
trucks and
up to 10
seconds for
ambulance transporting
patients
Typical Cost:
- Approximately
$2,000 (2004 estimate)
Are there any drawbacks
to speed humps?
Some of the disadvantages
include:
- Residents
living near Speed Humps
must tolerate
increased
noise levels
as vehicles
traverse Speed
Humps
- Traffic may
be diverted to previously
quiet parallel
streets
in the neighborhood
- Emergency service response
time suffers
- Speed Humps require signing
and striping,
which some
residents consider
unattractive
How can I get
a Speed Hump
on my
street?
Residents have
several ways
to request
for consideration
for
Speed Humps/Speed
Tables
on their street.
Speed Hump
Process
- A resident
may request
the City
to consider
a particular
street
for Speed Hump
or Speed
Table
installation by attending
a
Transportation
and Safety
Commission
meeting
and making
a request.
Meetings
are held
on the
third
Wednesday of
each
month
at City Hall
(Council
Chambers)
located
at 117
Macneil
Street, by
contacting
the Public
Work
Department at (818)
898-1222.
- The
concerned
resident
may be
asked
to circulate
a petition
in
the neighborhood
which
is being
considered.
The petition
will
be supplied
by the
City
staff.
The number
of persons
signing
the petition
in favor
of the
installation
of
Speed
Humps or
Speed
Tables
must
represent
at least
2/3
(67%)
of the
total
number of
homes
along the impacted
residential
street. Residents
submit
a
signed petition
back
to
the City.
City
staff
will
then
verify
the
petition
results.
If
a petition
in
favor of Speed
Humps
or
tables
is
received, a
speed
survey
will
be
conducted to
support
the
residents concerns
of
excessive speeding.
Excessive
speeding
is
defined
in
the Citywide
Traffic
Calming
Study
on
file in the
City
Engineer’s
office.
Once
determined
that
excessive
speeds
are
occurring,
and
the
adopted
Speed
Hump
or
Speed
Table
policy
is
met,
residents
and
staff
will
work
together
to
determine
appropriate locations
for
proposed
installations.
- If, at a
future time,
residents want
to remove
Speed Hump,
they must
submit a petition
with
at least 51%
approval of
the original
affected
neighborhood area.
If approved,
residents must
pay to
remove the humps.
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