HomeMy WebLinkAboutItem 6.3 Sierra Ct Speed Limit (2) C o,z,D
CITY OF DUBLIN
AGENDA STATEMENT
MEETING DATE: August 22 , 1983
SUBJECT Ordinance establishing speed limits on Sierra Court
and Sierra Lane
EXHIBITS ATTACHED August 8 , 1983 Agenda Statement ; Traffic Engineer' s
Report ; Ordinance
RECOMMENDATION V: Waive reading and adopt ordinance
FINANCIAL STATEMENT: See attached
DESCRIPTION At its meeting of August 8, 1983, the City Council
introduced an ordinance changing the prima facie speed
limit of 25 mph to 30 mph on Sierra Lane and on
Sierra Court from Dublin Boulevard to Trinity Court .
It is recommended that the City Council waive the
reading and adopt the ordinance .
COPIES TO:
TTFM TTf
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CITY OF DUBLIN
AGENDA STATEMENT
MEETING DATE: August 8, 1983
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SUBJECT Speed Studies - Davona Drive , Sierra Court , Sierra
Lane, Starward Drive , and Trinity Court
EXHIBITS ATTACHED Traffic Engineer' s report dated August 2 , 1983
6(Ordinance
RECOMMENDATION 1) Waive reading and introduce ordinance
: establishing speed limits on Sierra Court and on
�. .Sierra Lane.
2) Authorize installation of additional 25 mph. sign
for N/B traffic on Starward at Gunshot, and 25 mph .
signs on Sierra Court , north of Trinity Court and
on Trinity Court .
FINANCIAL STATEMENT: Cost for installation of speed limits signs
approximately $100.00 each ( $700.00) total. Sufficient funds have been
budgeted.
DESCRIPTION:
The Traffic Engineer has undertaken several speed studies as the result of
requests from residents and the Police Dept. to investigate speeding
problems in various areas around town. As indicated in the Traffic
Engineer' s memorandum ,(see attached) , stop signs , reduced speed limits , and
traffic humps are not recommended to control speed at those locations
studied.
The Traffic Engineer has recommended establishing speed limits in the
industrial area on Sierra Lane and on Sierra Court from Dublin Boulevard to
Trinity Court at 30 mph. These streets are zoned and not posted and,
therefore, a prima facie speed limit of 25 mph currently applies .
The Traffic Engineer has also recommended posting 25 mph signs on Sierra
Court north of Trinity Court and on Trinity Court. These streets are also
unzoned and not posted. The current prima facie speed limit is 25 mph.
Lastly, it is recommended that an additional 25 mph sign be installed for
northbound traffic on Starward at Gunshot .
It is Staff ' s position that these modifications will reduce confusion for
motorists in those areas studied and provide a more realistic speed limit
where warranted.
With respect to the speeding in the vicinity of Davona Drive, it is Staff' s
position that radar enforcement would be the only effective tool in
reducing speeding on that street . If the City is successful in its
application to the State Office of Traffic Safety for a city wide traffic
study, Staff will be able to address the utilization of a radar in a more
comprehensive manner.
ITEM # . 8. , • COPIES TO:
1 km
MEMORANDUM
DATE: August 2, 1983
TO: City Engineer
FROM: Chris Ki n zel
SUBJECT: Result of Speed Studies
I have completed an investigation of requests made by Dublin residents
concerning speeding problem on various streets . As a part of our
investigations , we obtained radar speed checks on each of the streets
from unmarked vehicles for the purpose of determining prevailing
motorist practices . We also made repeated field surveys of the area in
order to observe problems and possible solutions first hand.
Two general conclusions stem from these surveys. First , there is a need
for Dublin to continue the practice of establishing 'realistic' speed
limits . Unrealistic speed limits are those which are lower than
practical with the attempt to significantly and permanently lower"
vehicle speeds . Studies performed throughout the state and the nation
prove that motorists ignore unreasonably low speed limits regardless of
. the degree of enforcement . While it is hard to believe , on a given
stretch of roadway , average speeds of motorists will not change
regardless what speed limit sign is displayed or even if there is a sign
at all . Most motorists choose their speeds based on observed conditions
at the time on the street in question . Speed limits have as their
primary purpose the guiding of unfamiliar motorists and the setting of
enforcement limits .
The second general conclusion from the survey is that the use of radar
for speed enforcement would allow the Police Department to enforce
speeds more effectively. The use, or threat , of radar by police could
affect the speed of motorists who might otherwise select unreasonable
speeds. The City still hopes to receive a a grant from the Office of
Traffic Safety to fund portable radar sets for use in police vehicles.
Residents along streets with prevailing speeds greater than 25 mph tend
to request STOP signs , humps , dips and related devices in an attempt to
curtail speeding . The general experience is that these devices are
ineffective in reducing speeds along the street . On occasions , where
the street is used by "through" traffic , the device can become
sufficiently annoying to direct traffic to other routes .
City Engineer -2- August 2, 1983
A few cities in California have installed humps on streets with on-going
speeding problems. Because they constitute an added 'hazard' , they have
a potential liability to the public agency. They are , however ,
effective in reducing speeds near the installation.
Our survey included the following streets : Davona Drive , Starward
Drive, Sierra Court and Sierra Lane.
Davona Drive: In 1982, the City Council authorized STOP signs at two
intersections along Davona Drive . Since their installation , there
continue to be complaints of speeding . Over the years , traffic
engineers have noted that the use. of STOP signs for speed control is
ineffective. Motorists tend to roll through unwarranted STOP signs and
then make up for lost time by going even faster. In the case of Davona
Drive , we have not made STOP sign compliance checks but in our most
recent radar checks we have noted that speeds have not reduced since the
placement of the STOP signs . We made a total of 12 radar checks at
different times and locations along Davona Drive and found that the
average speed is still about 30 mph, and the speed driven at or below by
85 percent of the motorists is still about 35 mph.
With these findings, we cannot recommend any additional STOP signs nor
do we recommend a change in speed limits . It is felt that traffic
conditions on this street would be susceptible to improvement by radar
enforcement .
Star ward Drive : This is a collector street more local in nature than
Uavona Tra is speeds on this street also average about 30 mph.
Starward has relatively sharp curves at both ends and there have been
speed-related accidents in the past along the street. It was observed
that the existing 25 mph sign for northbound traffic is located near
Amador Valley Boulevard near businesses rather than near Gunshot Lane ,
which is the start of the single family residential district. We are
recommending an additional sign near Gunshot Lane.
Again , the specific problem on this street lends itself more to an
enforcement solution than by any change in signing or regulations.
Sierra Court : This street is unzoned at the present time and is the
location of numerous business and manufacturing establishments. A speed
limit is appropriate and, based on our surveys and driving of the area ,
a 30 mph limit is recommended between Dublin Boulevard and Trinity
Court . From Trinity Court to the north end of the street , a 25 mph
limit is recommended. In this northern section , the roadway has curves
and the safe speed is lower.
Sierra Lane : This is also an unzoned street in the business and
manufacturing district. The recommended limit for Sierra Lane between
Sierra Court and Dougherty Road is 30 mph.
DIY
TABLE I
COLLATION OF RAW RADAR SURVEY DATA
LOCATION OF SAMPLE* AVERAGE CRITICAL 10 MPH EXISTING RECOMMENDED
(50TH) (85TH) PACE SPEED SPEED
(DIRECTION) SPEED SPEED SPEED LIMIT LIMIT
Davona Dr e/o Briarwood Ln 29 33 24-33 . 25 25
(EAST)
Davona Dr e/o Briarwood Ln 30 35 26-35 25 25
(WEST)
Davona Dr s/o Bluebell Wy 32 36 29-38 25 25
(NORTH)
Davona Dr s/o Bluebell Wy 29 34 27-36 25 25
(NORTH)
Davona Dr s/o Bluebell Wy 31 34 26-35 25 25
(NORTH)
Davona Dr s/o Bluebell Wy 33 36 27-36 25 25
(SOUTH)
Davona Dr s/o Bluebell Wy 30 34 26-35 25 25
(SOUTH)
Davona Dr s/o Bluebell Wy 30 36 25-34 25 25
(SOUTH)
Davona Dr w/o Chatam St 30 35 26-35 25 25
(EAST)
Davona Dr w/o Chatam St 31 34 27-36 25 25
(WEST)
Davona Dr w/o Village Pkwy 30 36 26-35 25 25
(EAST)
Davona Dr w/o Village Pkwy 31 36 28-37 25 25
(WEST)
Sierra Ct n/o Sierra Ln 33 39 28-37 25 30
(NORTH)
Sierra Ct n/o Sierra Ln 34 38 29-38 25 30
(SOUTH)
Sierra Ct n/o Trinity Ct 27 34 21-30 25 25
(NORTH)
* Not necessarily indicative of entire street
0 •
TABLE I
COLLATION OF RAW RADAR SURVEY DATA (CONT.)
LOCATION OF SAMPLE* AVERAGE CRITICAL 10 MPH EXISTING RECOMMENDED
(50TH) (85TH) PACE SPEED SPEED
(DIRECTION) SPEED SPEED SPEED LIMIT LIMIT
Sierra Ct n/o Trinity Ct 28 34 22-31 25 25
(SOUTH)
Sierra Ln e/o Sierra Ct 30 35 26-35 25 30
(EAST)
Sierra Ln e/o Sierra Ct 29 35 25-34 25 30 •
(WEST)
Sierra Ln w/o Dougherty Rd 29 34 24-33 25 30
(EAST)
Sierra Ln w/o Dougherty Rd 30 35 25-34 25 30
(WEST)
Starward Dr n/o Gunshot Ln 29 35 26-35 25 25
(NORTH)
Starward Dr n/o Gunshot Ln 31 34 27-36 25 25
(SOUTH)
Starward Dr s/o Hillrose Dr 30 34 25-34 25 25
(NORTH)
Starward Dr s/o Hillrose Dr 29 32 24-33 25 25
(SOUTH)
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ORDINANCE NO. - 83
AN ORDINANCE OF THE CITY OF DUBLIN
ESTABLISHING TRAFFIC REGULATIONS
The City Council of the City of Dublin does ordain
as follows :
Section 1 . SPEED LIMITS :
Article 18 , relating to "Speed Limits" , of the
Alameda County Ordinance Code previously adopted by the City of
Dublin is amended by the addition of Section 6-628. 31 and
6-628. 32 to read: Thirty ( 30 ) Miles Per Hour (MPH) .
6-628. 31 Sierra Lane
6-628. 32 Sierra Court from Dublin Boulevard to Trinity Court
Section 2 . POSTING OF ORDINANCE
The City Clerk of the City of Dublin shall cause this
ordinance to be posted in at least three ( 3) public places in the
City of Dublin in accordance with Section 36933 of the Government
Code of the State of California.
PASSED AND ADOPTED by the City Council of the City of
Dublin on this 22nd day of August , 1983 , by the following votes :
AYES :
NOES :
ABSENT:
. . . . . . . . . . . . . .
Mayor
ATTEST:
By
City Clerk