HomeMy WebLinkAbout0186.091Karch 21, 1991
HONORABLE CITY COUl<CIL
Palo Alto, California
Use of Road Humps 00 a Citywide Basis
Members of the Council:
REPORT IN BRu;r
9
The purpose of this repoct is to present supplemental information
followinq the November 20, 1990 Policy and Procedures Committee
~iscussion on the citywide use of road bumps. staff recommends
that council approve the re.ised procedures and guidelines for
application and desiqn of road bumps (Attac~ent 1).
SUMMARy OF THE NOVEMBER 2 Q POLICX AND PRQCEOUPjES COMMITTEE MEE~.-ING
Tbe discussion of the policy and Procedures committee focused on
staff's recommended procedures and guidelines for application and
desi9n of road bumps (CMR~S69:0, November lS, 1990. pages 6-12);
and a study of primary emer-qency routes for the Fire Department
(CMR:569:0, page 5).
The committee voted not to recommend a stu~y of primary emergency
route5~ The Committee voted to recommend approval of staff's
procedures and guidelines for road bumps, with one modification:
that criterion 12 under "Operational Criteria-be changed fr:lm
35 mph to 32 mph (CMR:569:0, page 10).
Additional comments from-Committee members included a request that
sta~f consider making t~o further changes to the procedures and
quideline.s:
1. Under Section A, -Administrative Procedures-. items '2 and #3
(CMR:569: 0# paqe 7), staff should determine if the street a1 so
meets Operatio~l criteria '1 ~~ f3. provided that data were
readily available, before asking the request"'!:' to submit a
signed petition.
CMR: 186:91
---,.,.,..,,~ . .;,..-----
o
2~ Under Section 0, ·Design of Road Bumps·, item 13, Exhibit C
(CMR:569:0, paqe 12 and Attachment 9), reconsider ~hether or
not having a sign at each bump is necessary, and whether or
not greater a~vanced warninq of the 15 mph advised speed could
be provided.
The committee also discussed the relationship bet.een the spacing
of bumps and the committee's recommended qualifying speed criterion
of 32 mph. No consensus was reached regarding changes in staff's
recommended spacing.
REVISEP RECOMMENDED PROC~QURES AND GUIpELINES
In response to the committee's recommendations and requests, staff
bas aodified appropriate sections of th~ procedures and 9-uidelines.
In addition.. staff has reduced the spacing between :bumps as a
co<nsequence of the Co~ittee' s lOloilering the qualifying speed
criterion from 35 ~ph to 32 mph. Staff has also made a few other
changes .hieh are unrelated to ~he committee's discussion.
The recommended procedures and,_ 9uid*'!lines;; ,frolll ~:569:0 ,eire
p!"~~~n~ed ~low in it-lic type. it;~~'kJ"l'!'~i:.1iIf<i4.~' $(ni:iith~f._jtt.e f!te~!ifti.:M~"fi!flfj4(#i.:J. (Minor revis10ns ~ave not been highlight
ed4) Follov~nq each h~1hl!qhted revision 1S a short discussion of
tbat revision in non-italicized typ~. Attachlll.ent 1 is the complete
set of revised procedures and guidelines, including all proposed
changes, but cleared of all discussion comments, hiqhlighting, and
italic;s4
PROCrnJRfS N/Q GUlOHIN£S FOR APPLICATlON AHD !l{SlGN OF RON2J1VI!PS lit PAID AUSl
~, Ad_fnistr,tfve Procedures
The steps of this procedure are illustrated as a tlow chart in
Figure 1~
1. A request for road bumps IUIst odgfrlate frell iI resident of t,~&
street en which the blimp is desired~ That request may be forwarded
through tht neignborhoDd ilssociation representing !~at area~
A1t~,..native-l,~ staff IN! suggest h I' resident who has (Oed a
cOMp1ilrlt relating to his or her street that road bumps II-al be all
,ption fer ,ddressfng tfj~ comp7iint (in tI"ich else the next step
would b~ skipped).
2~ if the street meets
~~~i;~1~~~~i.:~ tf <f~tf·i:r.aan, .4 cu,.~or' de.te .... i.a·
guidel,ines i" Section
fdt.~~~!;!1: If the street does eo the reque.stD"r in
the Oepartfllent that I speed compl.fnt has
.ay need enforcement action_
CHR:186:91 3/21/91
Page 2
,
~ , ~ B.M' A!MNST'AAllVE ~~. ii:.. ___ .;,F .. IGYlE;;;.;-.'
PfKIJ[CT OfYELOPl!Etfl c£f 55: v
No
No
No
No
yes
Report to Council
Refer to P and P
Yes
Evaluation of Basic Criteri~:
-local resident;ill street
-speed limit 25 mpo or less
-logltol segment; 500 feet to endpoint
-not a truck, bus or primary emergency ro~te
-rade ~at to exceed S percent
Eyal~atfon of Neighborhood Criterion:
-2/3 of residents of street sfgn petition
£Valuation of Operational CrlterL~
-85th percentll. speed 3S mph or oare
-AnT between SOO and 4000 vehic12s
-6 or rIOre speed related ac{:idents in pneceding
three years.
Determination of Bumo locations;
-number ind loeation of bumps
-tr;ffic diversion and mitigatfon study
-neighbQrhood meeting
-staff recommendation
FUNDING PROCESS:
Implementation
~~----------------.
. ,
,
./
---.-_\_-~-----.----------, .. -_._.----. ----' ........ _'._--
o
This change and that in item '3 below had been requested by some
co~ittee .eahers. The change. qive statt the flexibility to use
all readily available data to determine whether or not a street
passes the -first level evaluati~n· before the requestor is asxed
to circulate a petition~
J_
5_
~qut:;t.:t;m te°~~:r~ ~:~ su1!ftii'!~~fff'!!!(fPoJ/l'~f!;'Je'/~;
the Cit,) "Mch estilb/fshes the extent of neighborhood support (two
thirds, .s exp1.'ned fn Sectfon 8)_
After st.ff receives .nd ~erifies the petition, stiff wi11 gather
tr,ffic data in ,,,..der to detefYJine if the street meets the Opera
tio,," C,.it~ril Jisted i" Section 8~ If the street does not Meet
the Oper.tfona1 e,.,·teri., staff win sa infol'1l the reqClestor in
writing, and .dvfs~ the PQlice Oepart.eent that a speed complaint has
been receh'ed th,t 1IIi,1 need enforct!lJtent Iction~
If the street wets .11 the criteria listed in Section 8. staff wn 1
conduct" ""r. thorough ev.'udfon~ induding:
.-
This change is the consequence of a change in basic criteria '3, 8S
explained later.
b. The extent of the are, where traffic diversion might occur
will be deteNlined. The UJOUnt of traffic diversion fro.1JJ the
e'igible C·prflNry-) street to other (·secondary·) streets in
this are. wi1i b4t esti.,ted. TraffiC speed and VO;IIRte dat, on
t~se secondary streets will be co]]ect~.
c. If CJecess'rJ~ .ftfgaHof! lIe,sures f~r the secondary streets
wil1 be proposed. If read bl.Jmps ilre pfaposed as lDitfgatio.1
aeasurEs, the secondary streets sha11 ~et as ..ca·'1Y of the
e1igibility criterfl listed in Section B ~s possib1e.
d. A nefghbcrbood aeetfng for residents of the primary and
•• cond8ry streets will be held_
e. A' report for City CouneiJ ..-11 J be prepl'"ed. It is anticipated
that this repDrt would be refe~rEd to the Pc1fcy and Proce
dures C~(ttee.
6. After Po7icy Ind Procedures Comittee review. the request wil1 be
forwarded to the Cit.! CQunci1 fo,. p,.og"lm~ but nat funding •
• pproval_
3/21/91
Page 3
~
\
"
8.
" -,
If Ctty CDunet] .pprovu tilt! reid bu,1tp reqlJ~$t, the pr-oject will be
consid.red for funding 'ppro¥ll by Inclusion in the Cap,-t.1
1.1"D~ .. nt Progr .. (eI,) intlrn,' staff screenir:g procea IfIhich
nOMOlII, begins f. Ceceeber of •• ch , •• r.
If rpprov«/ during th, sCrfer:fng process. the road bump project 14'111
b. Incl.dod in tho CIP which tho Cit, " ... gor reco_nds to the City
Councf1. In flay of .,C~ y •• r. the reco-.rtded CIP is transmitted to
the Cft.1 CQuncf 1 for cons iderat io" I.I)(! approvil. 'til pubifc hearings
berGr, th~ Fi",ne, and Public Works Co.afttee. (Note that i road
~ prGject ~l? Meet .11 crfteri, .nd gufde1ines. but cou1d stiTl
f.f] to receive funding .pprov.1 in th~ C[P.)
9. Ro.d bumps .,, be considered for relllOvaJ under a simf7ar pracedure.
L ([!'f,riA fer Ddrnafnat(on 9' lljqib'e Street Segments.
A street seg.ent (or streot) f •• llgib1. for ro.rI bu,"'Ps if ill of the (allowing
'·rit~rjl .~ _L
• B.sfc Criteria
• Neighborhood Support Criterion
• Oper.Hona' CrHeria
Basic Crit,d.
1. Th. street fs • 10c.1 street .s deflood by the P,lo Alto Comprehen
$f~f Plan. and is predoeinlntl, resfde"ti,,1.
2. The prf/li f.cfe .r postod speod li"t! Is 25 "ph or less.
3.
This chanqe hi!!!& been made by staff. It deletes a somewhat
arbitrary fOrW!:er proposed criterion for a mirdmum segment length ~
In order to .eet this nev criteri~n, a street need only be lonq
enougb. to acco-.odate at It!ast one road bUlllp 'With a .2S0-foot
.ini.ua 8pacinq.
f. 111. stf'Ht ;$ not I designated truck or transit blJs route or a
prf .. ,., or rout in. access route for emergency r~hicTe$.
5. Tho '.ogitudin.1 grarle of the street doe. not exceod five perceot.
lefgbbcrhood Suppprt Crjterio~
I. Occup.nts of .t , ... t tOIo-tMrds of .11 dole I lings with .rld",s ••• 00
tho street whore butlps or. requestod to be Toc.ted sign. petition
requesting the buops.
C!IR:186:91 3/21/91
Page 4
..
~ ..
. .
. ---.---~-'-'--'-
o
Statf 'WIll ma:ke an initia.l determination ot the length of the
street to be included in the petition. As explained in ~Admlnis
trative Procedures·, ite: IS(a). a mere thorouqh evaluation of the
length of the street segment would be ccnducted after receipt of
the pet! t1 on.
Optr.tfpncf Crjtrrj.
l. The .v.r.g~ d.ily trlfflc (NJT) Is bet" •• " 500 .nr1 4000 v.hides~
2. The .~,.,erage 85th percentilf speed .'ong the segment ;s i minimum of
~,.,
This is a major change ~ecommended by the committee. The primary
impact ot reducing the qualifying speed from 35 to 32 mph is to
lessen the strictness of the qualit~·irl9 criteria. Staff still
believes th!llt only the most serious speeding problems should be
addressed by the use of road buaps. and those would be the streets
with speeds of 35 mph or above, as explained in CMR:559:0; page 10.
There are probably many residential streets that 'Would meE::t the
qualif'yinq speed criterion of 32 mph~ Thus, it is lik.ely th.'lt more
streets 'Would qualify for road bumps as a con.s:equence of this
chanqe. The relatively strict accident criterion ('3. belo",') still
remains as a li.iting ractor, however. None of the Midtown streets
which now have road bumps would hava qualified under the 35 mph
criterion, but would have ~alified under the 32 ~ph criterion.
Comaittee members, staff, and many Midtown residents agree that the
Midtown buaps have been succeseful. Staff still prefers the 35 mph
criterion tor the initial application of these procedures and
guidelines. but can s~pport the change to l2 mph.
J. At hut si-t reported speed-nllted traffic accidents hive occurred
'" the i/llllte(/iatel, preceding three consecutive ye,rs.
C. lQcltion qf Bold Bu.ps
1. The lIilliecJlI dista.,ce froll ~ri intersection to I road bump, "'here th~
street wfth the buRtP is , t/lrougfi street tifth no stop Sign, sha71
r,nge from 50 ta 200 feet. depending ~,., the type of intersection.
1. A ro!d bump shan not be installed 'fIitbflt l sharp harilontal curve
(gener,' iT • curve of 7en tftar; 300 feet centerline r~dfiJs) or
wftAiR 100 feet of the beginning or end ~f such' curve.
J. The first road butlp .It either end of I series shalJ be placed such
tll,t i warnieg sign can In iFfst.a] red before the bump at a df5t~nce
eqUi) to at least the .i~jmu. safe stopping distan,e~ based on the
•• 'st'ng 85th percentil. speed.
f. MY road bump shall be vi:5ib1e tOi oncOiming tra(fic fo!' ,t least the
.iDiau" safe stopping distince. based on the e.dst (fig 0" expected
85tk percMtiTe speed.
CMR: 186, 91 3/21/91
Page-5
5. A road bump shan not be p1lced over .anhaTes. catch basins, 0"
other ~tjl;tr access p~int$.
6. A road bump sha11 onTI be located where it does nat CiJUS~ a
subshntif7 Id'lerse impact on estabHshed dr' ("age patterns.
l~ .. road bullp s.~a1J on1, be Tocated wh~"e ., curb. poTe, tree, or other
obstructirm (,xf$ting or new) ~olJ]d block traffic fro(l drivir,g
IroUnd th~ end of the bump.
8. The folJowing guldelfnes should apply "here feasible.
•. ROld bumps s~ou1d be pl1Ced nelr street7ig~ts.
b. iload bumps should not be IOCited i""n,,':Jiately adjacent to
dr-iveways.
c. ROld bu~s lnd re!dtd s;gning shou1d be loclted on prope,.ty
lines, and where shrubbery. fences or other obstn1l';tions
interfere "'it'" the direct vjew of the bumps fram reSidences.
D. Design qf R9~d Bumes
1. A road bump shan be t"ree inches high at its midpaint (to1erance of
-O~ +0.25 iflches), and 12 feet wide ill the direction af travd ~ as
shown in f."fblt B (p.rt of Attachment 1).
Z. and a stop
di.,ce,ntfnulty "hfc~
451] to 551J
is less tha.n
If tltere are g;;ei'~~r~~,~~!'r.nSJoOl"fa,tfC" Divis jan,
staff still prefers the nominal spacing of 500 feet • .....-hich results
in an 85th percentile speed bet'We.an road humps of 30 mph. as
explained in CMR:56S:0. page 12. (After crossing a road bu~p. d
driver accelerates until approximately half-way to the next road
bump. then decelerates. When a radar speed o~servation is ~adc~ a
drlvert$ maximum speed is recorded. This is referred to as the
spe.ed between road bmtps.) Exception (a) has been develop'6:d by
staft as a consequence of the committee'& recommendation to lower
the qualifyirua speed to II lIIph. This spa~ing range would result in
a range of 85th percentile speeds between road bumps of fro~ 27 to
30 apb, thus qiving staff the latitude to select a spacing Yhich
produces the desired 5 mph speed reduction wh~n the pre-road bump
speed i$ as low as 32 mph. Staff believes that it is net ~orth the
cost and other impacts of road b\..lInps to install them 'Without
reducing the existing speed by at least 5 mph.
Exception (b) has been developed by staff because there could be
unusual circumstances in vhich it might be advisable or acceptable
to reduce speeds to 25 mph betW'een road bumps. One such
CMR, ]86: 91
: -.' '
3/21/91
Page 6
.~ ...
circUlIIst.ance .ight be .eli street seqll1:ent that e¥ceeds all qualifying
criteria for the installation of one road bump, except chat the
mini~u. 350 teet spacinq CQuld be realized or. only one side of the
bump, vhile at least 250 feet could be realized en the other side.
J~ Signing and striping sf/aH be ;"n accordance lIIith f)J}ibits,~ flnd C
(p.rt .f Att.chmeot 1). .
As a result ot the committeefs ':iiscussion, statl has modified
Exhibit C aa tollows: The -15 mph-~arnin9 sign ~ill not be placed
on the sign pole next to each bump. Instead it will be placed only
at the beqinninq of the street segment (and on side streets), on
the same pole with the -Sumps Ahead-sign. Staff has determined
that the -Bump· sign should remain at each b\.nII.p because it is
recommended in the informational report of the California Traffic
Control ~vices cOm:fll:ittee, a.nd in-the draft quidelira~s of the
Institute of Transportation Bnqineers~ Staff believes that the
additional warning provided by the -Bump· $ign is needed in case
the pavement aarlc.inqs are obscured by other vehicles, and to
maintain a lower liability exposure for the City_ Staff supports
this chanqe because it will reduce the number of signs at each bump
and p~ovide q~eater advanced warning of the advisory speed limit.
Staff has also .ade a ainQr modification to Exhibit A, ~hich had
incorrectly showed the spacing bet~een stripes to be five feet two
inches. The correct spacing is three feet_
STATUS OF OMIT GUIDELINES or INSTITUTE OF TRJ .. NSPORTA,TION ENGINEERS
The Institute of Transportation Engineers (ITE) has developed draft
guidelines tor road bumps. These were discussed by the ITE pcli~y
committee in January 1991" but no action was taKen. It is now
expected that the dr.1ft guidelines 'Will be published for the
purpose of allowing approximately one year af public discussion.
Next year, they will be conside~ed by the ITE executive board for
possible tinal approval. lTE has already implicitly approved the
use of road bumps under interim gUidel ines. because they are
sanctioned as a traffic management tool in the 198; ITE publication
Resigential street Oe~ign and Traffi_t::_S.9ntrol.
According to the proposed Administrative Procedures, staff would
prepare a report for Council action for each eligible road burop
request (or for sever31 at a time), on an approximately annual
basis~ Even if no eligible requests were received, staff antici
pat~s that it would still provide Council an annual information~l
report~ Because the proc~ures and guidelines have not yet been
applied in Palo Alto (e-xcept for the design guidelines, which were
tested in Midtown}, staff expects that some changes ~ill inevitably
be needed" based on experience~ The annual report -would he an
appropriate time for staff to identify possible changes.
CMR: 1&6:91 3/21/91
page 7
'.
" V
ENVIRONMENTAL ASseSSMENT
Council adoption of the revised procedures and guidelines does not
constitute a project tor the p.urposes of the California Environ.m2n
tal Quality Act.
staff recommends that Council approve the revised administrative
procedures and quidelines for the application and design of road
bumps (Attachment 1).
Respectfully submitted,
£:iF~~
Transportatl Engineer
jdI~'ZAl
~~ETH R. SCHREIBER
Director of Planning and
Cemmunity Environment
city M naqer
Attac ants:
1. Procedures and Guidelines for Application and Design of Road
Bumps in Palo Alto (includes Exhibits A" B,. and C) (revised)
2. CMR:569:0" ·Use of P.oad Bumps on a citywide Basis-,
November 15, 1990
cc: Palo Alto Bicycle Advisory Committee
Stanford University (Julia Fremon, Andy Coty)
Bob Moss
Denny petroslan
Dena Kosar
Individuals in the following groups were sent a letter notifying
them of the availability of this staff report and the date of the
city Council mee~inq at which the report will be discussed:
Neighborhood Associations [from Planning Department list
updated July 1990J
People who have contactea: the Transportation Division
requesting road bumps [distribution list available in the
Transportation Division]
People who attended the January 10, 1991 meeting on "Midto~TI
Pedestrian Safety· [distribution list available in the
Transportation Division]
Relate4 staff Reports: CMR:471:9, -Kidtown Road Bump
Oemonstration--Final Evaluation Report-~
October 12, 1989
CMR:286:91
,
Page 8
3/21/91
•
o ,,--," ATIACHMENT 1
PROCEOORES AND GUIDELlliES FOR APPLICATIOIi AND DESIGN OF' ROAD BUl<PS
IN PALO ALTO
A. Administrative PIQCedurts
1. A request for road bumps must originate from a resident of the
street. on which the b\llllp is desired. That request may be
forwa.rded thr-ough the neighborhood association representing
that area .. Alternatively, staff 1I'la.y Sl!.gq'e-st to a resident "wo'lio
has tiled a complaint relating to his or her street that road
bumps may be an option for address.ir.g the cc-mplaint (in 'a!hich
case the next step would be skipped).
2. After receipt of a request, staff will determine if th.e street
meets the Basic Criteria listed in Section E, and, if data is
readily available,. Operational Criteria (1) and (3). A
cursory determination vill also be made of ~hethe~ any of the
guidelines in Section C would preclude the installation of
bumps_ I:-f the street does not meet these criteria, staff .... ill
so inform the requestor in writin9~ and advise the Police
Department that a speed complaint has been received that may
need enforcement action.
3. If the street does ~e~t the criteria identified in A(2}, the
requestor ~ill be re~~ired to submit ~ petition (forms
provided by the City) which establ.ishes t_he extent of
neiqhborhood support (two-thirds, as exp~ained in section e}~
4. After staff receives and verifies the petition, staff will
gather traffic data in order to determine if the street ~cets
the Operational criteria listed in section B~ If the street
does not meet the Operational Criteria, staff will so inform
the requestor-in 'fIo'ritinq, and advise the Pel ice Department
that a speed complaint has bcpn received that may need
enforcement action.
5~ If the street meets all the c-riter-ia Ijsted in Section 8,
staff will conduct a more thorough evaluation, including:
a. The logical length of the street segment 'Where bumps
should be installed and the number and location of
potenti~l road bumps on thi~ segment will be determined.
b. The extent of the area wher-e traffic diversion might
occur will be determined. The amount of traffic
diversion rr-om the eligible ("primary·} street to other
(-secondary") streets in this area will be estimated.
Traffic speed and volume data on thes~ secondary streets
will be collected.
~---'~-.. -.--
c,
d,
e,
. ~--. -,-_._-
If necessQ, aitlqatlon mC&:::iures to the second;:arj
5treets will be proposed. If road bumps are proposed a$
miti9ation .easures, the secondary streets shall meet as
.~ny of the eliqibility criteria listed in section B as
possible,
A neiqhborhood ~eeting tor residents of the primary and
seco~dary streets viII be held~
A report tor city Council will be prepared. It loS
anticipated tbat this report would be referred to the
Policy and Procedures commit~ee.
6. After Policy and procedures COml:littee revieW', the request 'Will
be rorvardad to the City COOncil for program, but not funding,
approval.
7. If city council approves the roatj, bump r'equeat, the project
will be considered for funding approval by inclusion in the
Capital Improvement PrograJl (elF) internal staff screeninq
process which no~ally beqins in Oeceaber of each year.
S.. If approved during the screening process" the road bump
projact will be included in the CIP which the city Manager
r~1DIends to the City COlJncil~ In May of each year" the
recollltended CIP is transmitted to the City Council for
consideration and approval" via public hearings before the
Finance and Public Works Committee. {Note that a road bump
projew-t .ay meet all criteria and guidelines~ but could still
fail to receive fundinq approval in tbe eIP.)
g~ Road bumps may be considered tor-removal under a similar
procedure.
B~ Criteria for DeterainatiQo of Eliqi~le Street SegMents.
A street segment (or street) is eligible for road bumps if all of
the following criteria are met.
• Basic Criteria
• Neighborhood support Criterion
• Operatione! criteria
.Basic Criteria
1. The street is. a local street as defined by the Palo Alto
Comprehensive Plan, and is predo~lnantly residential ..
2. The prlca facie or p09t~d speed liDit is 25 mph or less.
Cuidelines
March 21, 1991
Page 2
•
", "
/
"" " ,.--., 3~ Tbsl.". is n~Jnimulll requin.rr.E:ont fc-nu',,-_,r of bumps or length
of street where road L·) .... ~!J& i"Ize J.·1"'1~:~E'~, pro\1ided that there
can be at least 250 feet betioleen ~)'.·"ps or between a bump ane!
a atop 5i9n, sharp curve, jog, cul-~-sac, or other
discontinuity which reduces speed to approximately 15 ~ph.
4. The street is not a designated truck or transit bus route or
a primary or routine access route for emergency vehicles.
5.. The longitudinal grade of the street does not exceed five
percent.
tleighl?orbood Support Criterion
1. Occupants of at least two-thirds of all dwellings with
addresses on the street 'Where bumps are requested to be
located sign a petition requesting the bumps.
Operational criteria
1. The average daily traffic (ADT) is between 500 and 4000
vehicles.
2. The average 85th percentile speed along the segment is 21
.ini~um of 33 mph.
3. At least six reported speed-related traffic accidents have
occurred in the i:Bllediately preceding three consecutive years.
C I LocH ion 0 f Road Bumps
1.. The minimum distance from an intersection to a road bump,
where the street with the bump is a through street with no
stop alqnJ shall range from 50 to 200 feet, depending on the
type of intersection.
2. A road bump shall not be installed within a sharp hori~ontal
curve (generally a curve of less than 300 feet centerline
radius) or within 100 feet of the beginning or end of such a
curve.
J. The first road bump at either end of a series shall be placed
such that a warning sign can be installed before the bu~p at
a distance equal to at least the minimum safe stopping
distance, based on the existing 85th percentile speeQ~
Any road bump shall be visible to oncoming
least the mini.om sate stopping distance,
existing or expeeted 85th percentile speed.
traffi.c (or at
based on the
5. A road bump shall not be placed over manholes, catch basins,.
or other utility access points.
GUidelines
March 21, 1991
Page 1
."
A road bump shaC:>only be located where it<:les not cause a
substantial adve~se impact on established drainage patterns.
7. A road buap Bhall only be located where a cu~b~ pole, tree. or
other obstruction (existing cr new) would block traffic from
driving around the end of the bump.
8. The following quidellnes should ~pply where f~asible.
a~ Road bumps should be placed near streetlights.
b. Road bU2ps should not be located immediately adjacent to
drIveways.
c. Road bumps and ralated signing should be located on
property I1ne3, and where shrubber.l, fences or other
obstructions interfere with the direct view of the bumps
~roa residences.
p. PCsign 9f Road BumpB
L A road bump shall be three inches hiqh at its n'lidpoint
(tolerance of -0, +0.25 inches), and 12 feet wide in the
direction of travel, as sho~n in Exhibit B.
2. The spacing between road bumps or between a road bump and a
stop sign, sharp curve, jog, cul-de-sac" or other
discontinuity which reduces speed to approximately 15 mph,
shall range from 450 to 550 feet, except: (a) if the existing
8~th percentile speed is less than 35 mph, the spacing may
range fro. 350 to 550 f~et~ (b) if there are unusual
circuastanees, as determined by the Transportation Division,
the spacing may ranqe frOll 250 to 550 feet.
J.. Siqnlng and striping shall be in accordance with Exhibits A
and c.
Guidelines
xarch l!l, 1991
Page 4
~\
" .
•
,-__ PROPERT'~ li .... E
--------
"..A : ______ 1__ _ ____ L __
CURB,GUT T!::FI 5 SIDEWAlK ~ ___ WF
I r-----•
-. ---------
EDGE OF PAVEMENT OR Gl.'lTER LIP __ J it
_:i 8
, IL
l-.. , , -. • • --• -~ OF STREET-
TWO-WAr nUbW ~I:. ~AV_~~E: U~:-__ ~c:~ ~ 1~.
• -----<~-
"
I • , I
, I
r
\6'37 -----
-------
1
-~
I
I
*OtIIlllllUOtIa "I'll" FQfII.lI-FOOl Wlilo"tH MTWUII GI,ITrUl8.
DI.Ii!~1 WILl. YAJII" .. OIII DLf'I'Ie.I!!N1' ~DTH'.
pLAN
SPEED BUMP DETAIL
","OT f:;) SCAoL£ REV 3121191
EXHIBIT A
,
I........ Wl-ITE PAVE MENT MARKING
IW'E (R lHEIMF\..ASIO
12' R£Fl..ECTrJE 'Mfl'f "ST'RIPE I T'rPiCAU
rW'EOR~
( EDGE Of: PA~NT OR GUTTER UP
-,-------
C~B.GtJTTER & SIDEWALl!(
"ROPERT'" lif'lt:
•
•
•
--------"'FlO?E,",T'f UN€:
C'JRi3 &. GUTT£R
,-'SP""CT CONCRE~',; r'12~-:APe~,i
e:J~;..: """","""""",,-_::!w_:::,,=---:p; :c;, '.;::-±====:::::5z:-"/=' ="" =" ==::::::::I"" ::-J?:::-!!:'==-~",=--::::::==:::::;::. -==i-
TACK COAT
'-----EXlSTII'«J "'SPHAlT CONCAETE ""YEMENT •
SECTION A-A
.. co, TO SCAot.E
~-----. ----~------.-.-.
)6' T'lf.
"-------~~
~ ;. '" b :: ~ ~ ~ ~ '" 0
'" ~ ~ " ri
'" ~ ~ " " ': ~ ~ ;, 0 0 • 0
A~lTC~TE
----------1
•
T-.CK COAT
I
J
"
EXHIBIT B SEc:..uON B-B
"'or -0 SC~~~
•
/ ,y
/ /. '"
/,.1 "-( BUMP ,. ,>PEes
W37
--.
EXHIBIT C
tyPICAL WAR'fING SIGNJNsrA~tATlQ!'i...
'>!'-:--T\; 5:;"_"
nPJCAL WARNING SIGN INSTALlATION
::;:-:-;-SC~~L'--------.--------,'-,-,'------