HomeMy WebLinkAbout0569.000Novembe~ 15, 1985
HONORABLE CITY COUNCIL
Palo Alto, california
Attention: Policy and Procedures Committee
Use of Road Bumps on a Citywide Basis
Me~ers of the COUPcil:
REPORT IN BRIEP
t
The purpose of this report is to respond to Council's direction of
one year ago reqardinq consideration of fllture road bump
. installations, and to refer that discussion to the Policy and
Procedures comaittee~ staff recommends that Council: (a) approve
the use of road bumps as a spe.ed management tool ~ {b} approve
administrative procedures to.t' the c.onsid.eratiol'! of road' bumps and
guidelines for their application and desiqn; and (c] direct staff
to initiate a study to identify primary eaerqency routes.
This report includes a discussion of the performance of the Midtown
road bumps; the status of road bumps in other California cities;
the position or the california Traffic Cont~Ql Devices Committee;
why road bumps 41:e appropriate for Palo Alto; legal issues; the
opinions of other City Departments; cost and funding implications;
and recommended procedures aoo guidelines:. for application and
design of road ~ps~ The procedures and guidelines are the key to
the recommended program in that they define a strict policy which
insures that road bumps would be used very sparingly. ,
BACKGBOmlD
• The fin"1 eleae.nt of the Midtown Neighbor-hood Traffic study was
completed in Koveaber 1989, with council's final approval of the
road buap demonstration project. At that time z staff recommend~d
that consideration of further application of road bumps be deferred
fer a year. with the expectation ,that the California Traffic
control Devices Committee wo'Uld have developed statewide quidelines
for road buaps by that time.
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council had also directed staff to respond to recommendations of
tha Hoover Park Neighborhood Association reqar~inq the completed
Midtown Neiqhborhood Traffic Study. Staff's response is contained
in a sep4rlte report, CKR:568;O~
UPDATE OF PERFORMANCE OF MIDTOWN ROAD BUMPS •
In September and OCtober 1990,. statf remeaGured the traffic volumes
and speeds on the Midtown Etreets on wbich the eight road bumps are
installed. The previous measurements had been made in May and Jun.e
1989 (at the end bt the demonstr~tion project) and reflected the
changes caused by the installation of the bumps. The latest
measurements show that there have ~en no measu~able changes in
speeds and volumes sInce that ti.e (staff had not anticipated any
substantial changes). The data is presented in Attachments 1
and 2.
In the past year .. since final council approval of the Midtown
bumpsr the Transport3tion Division received one resident complaint
about vehicle noiee~ (This was an unsolicited complaint--residents
were not surveyed this past year about the bumps~) No complaints ..
incidents, or traffic accidents related to the bumps were reported
in the past year by the Police })apartment, Public Works Department"
:Risk Manaqer.. Palo Alto Sanitation company.. or the Palo Alto
Bicycle Advisory Committee. During this period.. the Fire
Departaent responded to twelve calls for emergency services in the
area wbere the bumps are located. Of those, three could be
considered potentially life-threateninq, where any delay is
important to the patients' outcome. Cne of these calls (on Marion
Ave~ue) required paramedics to perform cardiopulmonary
resuscitation on a patient .. and the patient did not survive~ The
Fire Department does not attribute the outcome of this call to the
presence of road bumps in the ~~ea~ The incident does, however,
emphasize the need for proapt response in life-threatening cases;
and for that reason the Fire Department is generally opposed to
road bumps ~
STATUS CF posITION OF CALIFORNIA TRAFFIC QQNTROL DEVICES coMMITTEE
The California Tra.ffic control Devices Committee (CTCDC), which
se-rves as an advisory comaittee to Cal trans regarding traffic
control devices, took no formal action on road bUMpS in the past
ye.ar, and none is expected~ However, CTCDC discussed rQ.3.d bumps as
an infor:rna:tional item in 1Ju1.l 19l90 r and C"I'COC reemphasized its
earlier conclusion thatl.they are pave~ent design features rather
than traffic ,ontrol I devices r and r hence, not under its
jurisdiction~ ,CTCDC noted that Cal trans has no interest in
developing geomatric design guidelines for road bumpsr and
recaa.~ that cities look to other sources for guidelines .. such
as tbf Inatitute of Transportation Enqineers CITE). An IT!:
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technical cOllUllittee hal!-recently ·jeveloped draft guidelines fo~
road bUlDf~e I but th-e rT£ .executive board ,.i11 not decide until
January 1991, at the earl iest, whettler or not to adopt these
quideli1lt!s formally as a ·recom."T,~r.·::L"d pr~ctice!ll.
ThUS,. ,*oac1~bumps hav~ the same stab .. s a~. they did last year: they
aloe c~sidered to be geometric aesig..'"' f-:·=.ture;;; yhich have not beer:
formally reeoqnized by Caltr;:inr:. ot" e.'I1Y other st.ate or national
agency or organization. Thel:'">;! are v~r:yin9 quideline3 for their
design and application, but tr.c:;:-e 9"')i 4~lin'!'s have not beer. adopted
beyond a local level. Even so, road bumps continue to be used in
increasing nUllll;iers, ... ith vruious ;.!esigns, in :many cities ,-'orldwidej'
incltldill9 many in Californi~.
Since the beqinning of the Midto· ... '1"', project., staff has heen in
contact with several C~lifornia jurisdictions t~at use road bumps.
Road bwups are being u~ed in inc.;reasing numbers in most of these
cities I with virtually no prcb"t:=:ls l~ally or ope'rationally. '!'h~
nUllber of 't.umps in these cities has increased b::t an averag.e of
about 40 percent in the past year. Some cities have adopted. a: very
liberal policy under ~hic~ road bumps are installed regularly in
.fairly larqe numbers; others have used them very sparingly. Of all
the cities contacted, only Menlo Park considers the use of road
bu.ps to be temporary, with removal of bumps anticipated once other
actions: such as road closures or-turn restrictions are. implemented ..
Refer to Attachment 3 for details.
fURTHER APPLICATION OF ROAD BUMP~_ PALO ALTO
Staff bas concluded that road bumps are an appropriate speed
management tool for certain situations, which would be determined
by the city council '$ appli-eation of strict procedures and
quidelines. This conclusion is based upon the tollowing
considerations:
• The Midtown derr.onstr-ation project has shown that road
bumps can be applied successfully. In Midtolam, they have
reduced speeds. and have since lila intained that speed
reduction, with limited negative side-effects.
• other co~on means of reducing speeds that Palo Alto has
investigated do not 'PPear to be always cost-effective,
reliable,\or suitable (e.g., regular Police Dep0ctmcnt
enforcement,., bulbouts l textured crosswalks, stop signs,
street closures).
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As. 1ft !ltidtcwn, roaJ b:..l;r'f"';; (..:;:[1';= ~;-I alt(Ornative to road
closures. Closures have be6.n c(lntroversi~l, prima:t'ily
because they sUbstantial-ly ch~T'ge tl"aftic patterns.
• Road bumps are !',eing uaed ami' accepted in ir.creasing
n~rs in nea~by jurisdictic~s.
• Compared to some other !w.('~2..SfJreS, such as c!,ntinuou£
Police Department enfo~c.ell:;.:~nt and full road closures.,
road bumps are relatively inexpensive .
, Disadvantages.
The 'tinal staff report for t.r.e MiJtolliT! road bunw demonstration
project pointed ~~~ wost of th~ pr~blems associated with road bumps
(CMR:.!-7.2:9, 10/12/89). The: lllajor CJ,GS are listed below:
• The Fire Departn:ent is QPpc.:ed to road bumps bocat.J6e {a)
they have caused increased response time on specific
route-s; (b} there is the p--=;ssibility of further injury to
an injured person beiT!q tl'"ansported by amhulanc2; and (el
bumps have caused injury and damage to responding
personnel and equipment (an incident thdt caused minor
injury to a driver was described in CKR:412:9, page 4).
• The Public Works Department is opposed to road bumps
because of the costs of cumulative long-term maintenance
without a cocmensurate increase in staff and budget.
o BUllps can cause some diversion of traffic to adjacent
residential streets.
. • Bwlps can create increased noise in their imDediate
vicinities due to increased vehicle bl"akinq and
acceleration, and equipment bouncing in trucks.
• Signing and stripin9 associated with bumps can have a
n~~ative visual iEpact.
• Bumps can be a nuisance and a general inconvenience to
the driving public~
.• There is no standardized design or accsptance of road
bumps.
Will I.syes
A full report on legal issues of road bumps, as they pert3lin to
Palo Alto. was presented in the final report on the Midtown road
buap project, and is i~luded as Attachment 4.
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QPINIONS Of CIT! PEPARTMENTS &~D O'rH_~.R ____ ~ITE.lAD GRO~i§
The Fire OepartJaent is strongly opposed to road b\.imps fer the
reasons stated on paqe 4. HO,"'~ver ~ the: Department recognizes rhat
there may be cvt:!rridinq publ i.e benefits which just,iCy the adverSE:
impact of road bumps ~n the Department's emergency responses~
The Fire Depart.ment would be willing to sllpp'.Jrt the furtper use cf
road bUlllf5 on r~dwa~~s that aid net serve as primary emergency
routes. such routes wOuld n~ed to bE: identified by ~eans of a
comprehensive citY'iide studi'o S~(..J.;:.ion 8 of th~ rec:om.Jr..;!r.ded
procedures and guidelines prElSellted l;:,.ter in this no.port does not
permit the installation uf road bumps on such rcutes. At this
time" however, the only primary eme.l.-g;zncy .t-e-utes that can be
identified would be the obvious ones, slJch as the rO_'3.ds in the
immediate vicinity of a fire 6t~tl~n, Gr a s~bdivision with only
one or two acce.ss roads. A CCIP.preh":'-:isiv~ si...udy of such routes
would Include the 'Jorle scope o'...ltl i:1c,j ir~ Attdchr::;ent 5, ,*,ould
require the services of a consultant, and may take about a year to
co:za.plete. The cost of the study is estimated to be approximate-ly
$ 35,000. Staff recommends t~lat such ? study :'e purs:usd. In the
interi., the Fire Department would participate in the review of any
streets on whi~h road bumps may be recommended~
The Public Works DEpartment is strongly opposed to road bumps
because of cumulative lonq-te~ increased ~aintenance costs. If
road ~umps were approved for application beyond the three existing
streets, Public Works believes that~ after a few years~ the need
fo~ additional funding and staff in the Operations Division CQuid
be substantial.. PUblic Works is also concerned about the illlpact of
road humps on drainaqe, especially on streets with no established
qutters. Section B of the recommended procedures and qul~elines
addresses the drainage concern by nvt permitting road bum~s to be
located on streets or in locations where inter-ference 'With drainage
would be substantial.
The Polic~ Department is not opposed to road bumps, ar~ supports
the ident!fjcation of primary emergency routes as proposed by the
Fire Oepart~ent.
Tbe Palo Alto Bicycle Advisory committee (PAEAC) believes that road
bumps do not appeer to impede or pose a hazard to bicycle tt"avel.
However~ a few individual committee Zlembers have reservations about
the increased ,use of road bumps. PABAC wants to insure that its
favorable posi'tion on road humps not be. construed to mean
acceptance of the abrupt speed bumps which are usually found on
priv"ate property. To this end, PARAe requested that the City's
terminology be changed from -road bumpsN to -speed humps-.
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Risk ",nagement is still not in agreempnt with the installation of
4 road tAlmps. :tiowever, as there h3V-~ be€:!1 no reported serious
inciaents or claims, there is no evi~epce that road bumps cause
increased risk to the City.
'Itle Finance Department t,('li~v€'5 t"at e.lw.y future toad bump
installation projects should c·--;:m;-ete with other 8.apit31 projects
for tunding. Even though the· cost: of a iiingle road bUl:lp is
relatIvely 5:.11'111, a typical project 1'I'-igh"t call for two tc four
bumps at a total cost of apprn)l'i~t:'.:t"""ly $7,500 to $15,000. The
.funding issue-is addressed in Section 'A of tha recol:lmended
procedures by which CQuncil-apprc."re.d road bump projects 'Would need
to be added to the Capi tal ImproveJ:1e-:-:lt. Pr09'l."alll. dev.alopment process.
The Palo Alto Sanit.at!on core.pany (PASCO,) is not opp<ls-ed to road
bumps, provided that the tleiq1"J,t is ;"0. q:reat_er than three inches and
the vertical clearance over the bU;;":f:-s is rlot ir.p.:l.ired.
pj;.O\...CiU"i''REii ilND GUIDELINES FOR .~ ___ p_~·n:_r~TrON JU~D D!(SIGN OF ROAP BUMPS
IN PAW ALTO
General Policy
Staff believes·that road bumps should be used primarily fo~ the
purpose of speed management. The ability of b 1m.ps to discourage
throuqh traffic should be considered or.ly as a secondary benefit in
conjunction with the primary goal of speed ma:1aqement.. Staff
believes that bumps should be used very sparingly through the
application of strIct eliglbility.criteria~ ~e reasons tor this
relatively strict apprvach are the following:
• Widespread use of road bumps could compound recognized
negative impacts, p~imarily the concerns raised by the
Fire and !'h.lbltc ~y-I:kS:': Depe\rt.~~t~t.s, tha aesthc-tic impac"ts,
and potential traffic diversion.
• considerable staff time ..,ould. be needed
small area study for each ""pplication
minimiz.e potential traffic diversion
residential streets.
to conduct a
in order to
to par-allel
• Though road bumps are relatively inexpensive~ a typical
application would probably involve at least two bumps at
a total installed cost of approximately $7,500.
The rgcoaaended procedures ana guidelines for design and
application of roa~ bumps are listed below in italics. [Explanatory
comments are non-italicized and a~e in brackets). The procedures
and quidelines are based on the findir~s of the ~CDC and other
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cali~ornla cities. They are similar to the draft ITE guidelines
sud. to thot;e of other local cities s~h as Menlo Park and
CUpertinO'. Should official guidelines ever be adopted by Caltrans,
IT'B or any othe.r recognized body, Palo Alto could modify its
guidelines eecordinqly.
A. 4dafpistr,tiyc Prqcedures_
[The steps of th:ls procedure are illustrated a3 a flow chart in
Atteclment 6. J
1.
2.
'3.
I.
5.
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A re<plest for road bumps ~st origil1at~ froa .i resident of the
street on which the bU8p is de'irod. That request II,Y b. '.rw.rded
through the neighbarho~d association . representing that ,rea.
A~ternatfve],1' staff lNy suggest to • resident who has filed •
ctnlphfnt relating to his !Jr her street that road bu1lfP~ "II be In
option for addressing the comp7aint (itt whiclJ case the next step
wo.ld b. ski ppod) .
After receipt of , request, staff wi' 1 determine if the street ft"ets
the 8ilSfc triteri" J istefl ff'l Slction 8~ If the street dJes not meet
th! Buic Criterfi, staff wili SG info,.. the req:;estor ia writing,
and .d~j5e the poric! Depal"t~nt that" speed comp1.int has been
recefved that tHy need enforcpment Iclioll. [This is similar to
the current procedure whereby staff determines
aainistratively that some requests for st.op siqns can be
dealt with tllr-ouqh other means. and so informs the
requestor.]
If the street does .et the B,s;c Criteril, the requestor wtn be
required to sub,.;t • petition (fa ... s provided by the City) which
establishes the extent af neighborhood support (two· thirds, IS
eXI',.fned in Section Bl.
After staff receives and '.Ierifies the petition J staf' ~i71 g,ther
traffic dlta iD order t~ determfne jf the street .,ets the
Operational Crfttrfj listed in Sect ien B. If the street does not
aeat the Operationl1 Criteria. staff wi J J so irrfo,... the requestor irJ
writing, 4!nd advise the Po1ice Department that a speed compl,/nt has
been received that •• y need enforce.ent action.
If the street ",eets al1 the criteria listed i" Section BJ staff vi11
conduct I I/IO~ thorough eVi1uation J including:
•• Ifullber and location of potentf.1 r.ad buRlps on the e1igibTe
street win be detertljned.
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b. The extent of the are .... he-,.-e tr"dfffc dj'{~rsfoft ,,-rpM lcc~r
will be detertrlirted. The ~mOl.mt of trdffic divers.ion froll the
eligible ("priMJry·) ,street to other ("secondary·) streets :"11
this ,,"e'ltIi71 be c:JU.'r.3~:;-~". T'("dffc speed and vo'lJfr~e duff on
-these sKanc1;}r/ strel?ts If':'.!' roE col1ected.
c.
d.
If necessary: .'1Ijtfg~tf""l ,rJl2"s:.'res fer the stcofidl7 stre,e,ts
w111 be prop!lsed. If rc;;1 t,~,_'1jpS Ire proposed is flIitiglt ion
lteiSVreS, the s~cor:ifU"l st,-e~ts slli!l} meet as .iny of the
r1igibiHty crite,"'i?; U!tr': h 5ectfon 8 1$ possibje.
A flefghbl)rhood meetifl9 (oJ;· r!Sfdents of the prf.ary and
secrmdary streets wn, b.a I!eid.
•. ... rl,Dorf far eft."! Cour)ci 1 ~f]} be prepared. It is anticfpat~
thilf this repfJrt itlQi.i7d be refErred to the Pa7fcy and
Procedures C"mmftte-s. [If several eligible r-equests
are processed in less than a year's period~ staff
aay combi~e these requests into one annual re~~rt
to Council. sir::.ilar to the procedure used for
eligible stop sig" ::-,:;!quests.]
6. After Policy and Procedure::; COIM1Htee review, the request If/in be
forwarded ta the Cfty Council for prograJfl, but not funding •
• pp", .. ' .
;. If Cit, Council approves the read bump request, the preject will be
consfder~ f-'Jr futrding approvaT by inc1usion in the Capita1
laprov~rlt Pf'09ram (CIPj interna.1 sta.ff screening process which
no~aJl¥ begins ia Dece~er of each year4
84 If Ipproved during the screening process, the road bulSp P,.oj~t tIIi11
"., inclutfed in the CIP wold the City Ifanager r.c ..... ods to the Cit,
C<nIncil. 1ft /lay af eadr yea,., the reco/l17;ended CIP is transllitted t~
the City CoclncH for consideration and approva1 f "fa pub1ic hearings
before the Fi!lfJnce and PlJbi i,:-;torks COlfJlfJittee. (Note that, road
bullp project may meet ,n crjteria and guide1ines, but cotJ1d sfil1 f.n to receive funding jppro'l11 in the CIP.)
9. Road buMpS "'Y be c~nsidered for re:8~v.] under I S1"j Tar procedure.
s. Criter;' for Deterflllinatfon of f1igib1e _~_r_~_t SecpJents.
A street segMent (·stree~·) is eJigib7e for rOad bumps if ill of the fe77ewing
crite~f. are .et.
• Buie Criteria
• Wefghborhcod Support Criterion
• Oper.tional Criterii
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[The eligibility criteria ar1ll the :key to the strictJ1tlss of the
reooaaended road buap progra.~ These criteria have been developed:
with the expr ••• purpose ot insuring that road bumps are used only
for the .oat serious speedinqtrroblems.]
Bas ic trUer; i
1. Tbe street f. • loe.' st~e.t •• defined by the P.70 ~Ito
Coapr,hen$ive Pian. and is prec!o,,,"n;tnt7,T rufd'fltfa1. [Collector
streets should not have road bumps. The purpose of
col 1 ector& JI even if residential.. is to facilitate the
flow of traffic to and from residential areas. They are
frequently used by eme.rgency, sanitation, and service
vehicles. Tbey qenerally carry hiqher volUDes than local
atreet., so a relatively small amount of traffic diverted
fros a collector could produce a relatively large
increase of traffic on a local street. Attachment 7 is
a map of Palo Alto's street network.]
t. The prfaa facie or posted speed "/i.it is 2S aph or I.... {All
local residential streets in Palo Alto have this speed
Ii_it. The advisory spee~ of 15 .ph at bumps would make
bumps inappropriate on streets with speed limits higher
than 25 aph because of the larqer speed differential that
the bu.ps would create along the street~]
3. Tbe segtll!nt /JIIIst begin .rod .nd at Iogie.1 p<>ints such '$ arteri.l
and co71ector streets l sharp c,"'rves l Jogs. cu1-d~-sacs~ or or other
discontfnuiHes. The segRfent !JUst be long enough that at least one
luJlIp can be inst,Hed t.:hjc" .-ets the distance requfreaents of
SectfDn D. it ... 2 (gener.l1, 800·1000 feet long). [Tbe minimum
secpK!llt lenqth is determined by the. .. ini.WI; bump spacinq
o~ 500 feet. A -logical ~eqaent-, as de~ined here, is
likely to have similar traffic cbaract~ristics along its
length: hence, all the blocks in the seqaent would be
likely to meet the ,eligi.bility criteria for bumps. Bumps
sbould not be installed in isolated or arbitrary blocks
of such a street segment.]
of. The street ;s not a designlted trock or transit b~s ro~te or ,
prf.,ry Dr routfn! access rout, for e.ergency vehfcTes. [If Santa
Clara County Transit District vere to propose moving a
bus route to a street on whlch there already were road
bumps, ana if this street were f"ound to be the only
feasible street tor the route, the road buzps would have
to be removed. J
5. The grade doe. not exceed fi.e percent.
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lie fghbprltood Suppa rt Crt t e.rLqa
1. Occupants. of itt feast two-thirds Qf an dwe'Tings with addresses on
t.lte stl*eet where bl.imps Uf req!.Jt:$~ ~d t" be IIcded sig.<J • petition
requesting the bumps. [This criterion ~cognizes that road
bumps are a ne-ighbo::.-ho<::,,-j i~ s·...\e fer \/hich thf'!!re should bE
IIlljorit.y support. It ~.lso ins:ures that a req'.lestClr is
concerned enough abGut the r~quest to ~ake the effort to
contaot the neighbor~ .... l"dch would be affected by the
'bu:e::>s. The petiti':)n is the f'or.nal means by which th1S
support is transmitted t·:'I t.he ci'ty. -Neighborhood-is
defined as the length of the street segment where bumps
are requested. This ~as already been determined by the"
application of ite~ thres of th~ Basi~ crit~ria4 Bumps
.iqht also ultimately ~e~d to be installed on parallel
streets, as explained in Section A, item five, of the
guideline.s. But, the ~nitidtinq petitio.1 'Would apply
only to the stroeet,s) cO!r.prising: the initial request~]
Operati9n.' Criteri.
L The average dai1, traffic (A,!") is between 500 and 4000 vehjc1es~
[Tbe lower limit recognizes that the absolute number of
incidents of s~edin9 on a low volume street is small,
and reflects tlle -worthiness" issuE!. ll'entioned above. The
upper limit recoqr-izE::s that the street, even though
local, serves a purpose ~imilar to a collector. In most
ihStances this limit would not apply because fev, if any,
local streets in Palo ~lto carry 4000 ADT.]
z. The ,fverage prevajling 85th percentile speed is a mi..,jIllUIJ of 35 mph.
[This is one of thE!. key criteria which is designed to
restrict road bumps to only the most serious problem
areas. Staff belieYes that 10 mph over the residential
speed limit of 25 mph is the beginnin~ of a potentially
serious speeding' proble'l:l. The Police Department normally
permits d.rivers lee.~ay of 5 mph over the speed limit, and
sometilles more. Furtbennore, staft is proposing that
bumps be spaced to achieve a maximwn 85th percentile
speed of 30 mph bet~een bumps (refer to design
guidelines, Se.ction D) ~ Staff believes, therefore, that
a road bump installation, to be ~orthy of its cost and of
any negative impacts which might accrue, should reduce
speeds by not less than 5 mph.}
3. At least si~ reported speed-re1it2d trctffic accidents have occurred
ill the iMedilt~1y precedfng three consecutiye years. [Thif;, is
also a key criterion of strictness. staff believes that
accident history should he an important determining
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~actor in wh.the~ or not a speeding preblem is judged to
be serious. In reality, this is a llberal standard, a~
the typical ~ltran. accident warrant for such ite .. as
installations of siqnals and stop signa on all types ot
strf!!eta" including residenti.al, is five accidents per
year.)
Locatiq" of Road BulRJ's . . ,
1. The .iRiau. distance frail in inter~l!'cf (on to I r(J-N bullp, tthere the
stroet "It~ the bu"", is • through street wlt~ no stop sign, shill
r.ng. f~ 50 to 200 fe~t, depending on the type of fnlersection.
{Driver. need thia d~ .. tance toO make judq:eaente related to
activities at the intersection, and &hould not be
distract""-by bU>lpo.) .
2. A lHnIp sha11 nat be instl1 Tfld with," • sh,rp horizontal curve
(genero1ly I curve of less than 300 feet ce.terlioe rldius) or
~fthi" 100 feet of the beginning or end of suclt , curve.
3. Tho ffrst buMp .t either end of • series sh.l1 be phced sucb that
I ".mini sign can be inst.l1ed before the buill' at I dist.nce equal
t. at least the aini"". safe stopping dfstaoco, bued on the
pre •• ilfng 85th percentfle speed.
4. AIry buap sh.11 be vi.,ble to Dnco"'ng tTiffic for at le .. t the
.ftti .. saf. stepping distl"ce~ bued on the prev,iJing Dr expected
85tlt percentile speed.
S. A bUip shl1l not be placed ,ver ~nho7es, catch ba$jns~ Dr other
utility ,ecess points.
6. A buill' sh.11 only be located where it does not cause. substanti.1
adverse .. "",act on established dr.in.ge patterRs.
1. A buMp ,h.l1 only be loc.ted "here, curb. pole, Ir"". Dr Dther
obstruction (existing or new) "ould block troff;c froll dri.ing
.round t~e end of the bullp.
8. The follawing guideline. should apply whero f .. sible.
I. Road buill's should be pl.eed n •• r sfreetlights.
b. Ron bullp' should not be locat"" i_iitel, adjocent to
dri"eways.
c. Rold buops .nd rellt"" .i9ni.g should be loe.t"" on property
liMS, and wh!re shrubbery, fences or ot~r obstructicns
int.rfere witlt the direct .iew of the bu"",s fro. resfdeoces.
t4'
CMR:569:0 11/15/90
paqe 11
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D. Qcsjon pf Rp~ Bumps
1.
• A raid lnJllp sha'l b~ thr'~~ i!i(;n€$ ;,,"gh a-t its midiJiJfnt (t"7er-a~Jce-of
-0, +0.25 inches), irld 12 feet "Nrc:? in tJ:e dfrection of trave1 ~ as
shawn in Exhibit B (part of AUdcM:eflt 8). [Most road bc.mps in
other cities are bet1.:£er. tr rE.e and four inches high.. A
three-inch high CUtl'.p is: ~referred, ~s it all.,ws for a
reasonable crossing "':;;C-2Q (15 r_ph advised} in relation to
the 2S mph resiC!~r.t.:al ~f0e:::! limit ... thus providinq a
smoother speed profile ale,] a $treet than with a higher
bump .. It: is re-ason;tl:::ly for:;i_vhl9 in abruptness to larger
vehieles such ap fiy~ ~y ~i~~s~ deliverI trucks and
sanitation vehicles. l~ tesults in less noise than a
higher bump .from eg;.:i:.-: -':o:",t bOlll'lCj nq in trucks and from
vehicle braking and ~c~81eration~ Three inches ~as the
~ominal height s,p€cifiea tor the: Midtown bumps. The z.ero
negative tolerance .... as r.ot specified for .Midto~.n and ~ill
insure that bumps are never le.s.:S than tltree inches high.]
2. The distance between ro,'Jd bumps Dr bctlt!een I raid bump Inri a stop
sign, shlrp cU"~'e~ jog, ,",,;7 -d~-sac~ or other discontinuity tMhich
reduc~s speed to iippro)';'rn~lf:!f 15 mph, 517;111 b~ SC.O feet (tolerance
of -101J~ +50 feet). [Th_is results in the desired 85th
percentile speed of 30 mph between bumps. Even though
the speed resulting tt"-,--r this spacing Is higher than the
25 mph residential spc.e-d limit~ staff believes that
d.rivers should be allol,o'!;d this latitude in choosing thedr
speed (refer to the discussion on t~e prev&iling speed
criterion in Section B of the procedures and quidelines).
On Co .... >per Street in the Midtown area., the 500-foot
spacing has produc~i. a maxlITlum 95th percentile speed.
between bumps of 30 1!'tph for tbe past tlfO years. Some
bumps in Midtown were purposely spaced less than 500 feet
so that speed reducticD at various spacings could be
tested.]
3.
CKR:569:0
Signing and striping shall be in accordance wHir Exhibits A ind C
(plrt of Atta-chmellt: 8) _ [This is the sa::ne strlpinq pattern
used for the Midtown bulT'.ps I excE'.pt that the placement cf
stripes has been slightly modified. A F~deral H19h~ay
Administration Study sho',.'s that the -ladder" marking as
used on the Midtown bumps is the type of marking most
conspicuous to a driver. It is al[l;;o difterellt than the
aarkinq Palo Alto uses for crosswalks, so bumps will not
be confu&ed with cross'Walks. This lllarking will be
retained.. Reflective paveroen';. tape or th.ennaplastic will
be used for bump stripes and legends, instead of paint,
and reflective markers will be placed on the bump along
the roadway centerline. Tape and thermoplastic retain
their whiteness and reflectivity much longer than paint,
and the centerline markers will add additional night time
visibility.]
11/15/90
Page 12
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COST Qr MAp IWMps AND FUNDING PROGRAM
The Public Works Department l which p~epared the bid docuaents and
adainistered the construction contract for the Midtown road buaPSI
estimates ~t the average cost per bu.p i. approximately $380<.
including preparation of plans, construction of bumps, installl!ltion
ot associated si9I1s and striping, and inspection. Future road bump
~o:1e~s would be aanaqed in essentially the same way as the
Mid.town project. That is, the Transportation Division 'Would desiqn
the PJ:ojectl the Publ ic Works Department \l'ould prepare the bid
documents, solicit bids~ and a~inister the const~ction contract.
A typical eligit;:le application for road bumps would probably result
in a ainimus rietd of two bumps~ for a minimum cost of about $7500
per elIgible application. This cost could rise cons:iderably i.t
other parallel streets needed the protection of bumps to minimize
potential traffic diversion.
Staff t.lee for processing an eligible road bump application,
including qatberinq technical data~ conducting a small area study
to identify potential traffic diversion l and prepar~tion and
presentation ot .an annual report to Council.. is estimated to
require a .inim~ of 80 to 100 person-hours.
It is not anticipated that enough applications ~ill be eligible for
illplementation to warrant an on-goinq road bump capital improvement
project. .Nevertheless~ staff believes that road bump projects
should co.pete with other c:api tal proj ects for fundill9 t as proposed
in section A of the recommended procedures and quidelines.
The Public Works Operations DepartJaent ~ould be responsible for
J%laintaininq road bumps. The Midtown bumps have not been installed
long enough to develop reliable long-term estimates of maintenance
costs, nor do other cities have this dat~. Long-term mainter~nce
issues include:. debris being left on the pavement by street
sveepinq machines when they cross a bump;-engine oil gradually
accu:ulatinq on the pavement, causinq it,s premature deterioration;
replaceJltent ot siqns and stripinq: and l'elJl,Qval and replacement of
a bump when the street is resurfaced. Public Works ' best esti~ate
of long-term maintenance costs is about $370 annually per bump.
Public Works' aaintenance budget does not include funds for this
maiutenance~
CONCWS1QN
Staff believes that, with the acknowledged success and approved
peraanent status of the road bumps in Midtown, it is reasonable and
appropriate to expand the potential use of road bumps as a speed
aanagezaent tool to other neighborhoods.. Essentially the same
considerations exist now as existed last year when Council
considered the approval of the Midtown road buaps on a permanent
CIIR:569:0 11/15/90
Page 13
f •
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basi •• J The procedures and guidelines discussed in ULla c-eport
abould ihSure that road bumps are inst~lle~ only in the most
appropriate cases, thus not creating a program 1fhich.~ is out of
proportion to the spe.eding problems, too expensi .. re.. or too
consuainq ol'.taft tbo A c1t~ .... ide Btudy of primary e1Derqenc'.l
routes. should help protecl important roadW'l3ye. fro~ impediments such
as road bWllPS end street clos'ures. Should Council not approve any
futuro us. of roa~ b~, statj believes that the eight r?ad bumps
in Midtown' IIbould remain permanently as a unique, effective
Qpproacb to the pa~iCUlar problems in that area.
ENYlBOtI!f!1fTAL MSISSMlWr
council adoption of the procedure a. and cri t2ria does not constitut~
a project for the purposes of the California Environmental Quality
Act (CEQA).
RI!COM!IEI!JlATIOI!
Staff r~s that council (a) by motion.. approve the
administrative procedures for the consideration of road bumps
(Attachment 8, Section A), ana the guidelines for application and
deGiqn of road bumps (Attachment S, sections B, C, and OJ; and (b)
direct stafl to develop a detailad scope of services and request
for proposals for a study to identify primazy ellergency routes
(Attaclment 5).
CMR't569TQ 11/15/90
Paqe 14
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Respectfully aub.i~ted,
E~EL~ t£n7Ull' i~7.jdzu:kf
KENNETH R. SC!rR.EISER )i
Transportation Engineer Director of Planning and
community Environment
;\
•
1. Midtown Road Bumps--Existin9 Speed Data
2. Midtown Road Bumps--Existing Traffic Volumes
3. status of R~d Bump Instal1~tions--selected Jurisdictions
-4. Legal Issu-es Pertaininq to Road Bumps
5. Tentative Scope ·of Work for a study to Identify Primary
Eme%gency Routes
6. Flow Chart for Administrative Procedures
7. Hap of Palo Alto street Network.
S. Procedures and. Guidelines for Application and Design of Road
BuE~s in Palo Alto (includes Exhibits A,B, and C)
cc: Palo Alto Bicycle Advisory Committee
~tantord university (Julia Fremon, Andy ooty)
Neiqhborhood Associations [from Planning Dept. list updated
July 1990]
People Who have contacted the Transportation Division
requesting road bumps [distribution list available in the
Transportation DiVision]
Bob )loss
Denny Petros ian
Cena Mossar
Related staff Reports: CMR:472:9, -Midtown Roadbump Demonstration
Project--Final Evaluation Report-, dated
October 12, 1989
CXR:569:0 11/15/90
Paqe 15
MICTOWN ROAD BUMP OEHONSTRATIOH PROJECT
COMPARISON OF 85TH PERCENTILE SPEEeS
...................................... _-............... _ ..................... , ..... .
85TH PERCENTILE SPEEDS (MPH. AYG BOTH OIRECTIOHS)""
OISTAHCE ~.------~-~-.------------~-y--~--~--.---.----------LOCATION 18ETWEEH Exp.ctod--I S.for. Hid After 15 110.
SUMPS based on Bumps Il<!noo Demo After
(f •• t) bump 5/88 1/89 6/89 D.mo
spacing* , 9/90
........ a __ ••••••••••• ___ •••••• _____ ••••••••• ____ •••••• ____ •••••• ~. ____ •••••
Marion 380 27 29 26 26 27
betwsar, bumps
Colopado 350 Z7 32 26 28 27
bet ..... n bumps
2500 blk Cowper I 500 29 31 30 29 30
bet ..... n bumps
2600 blk cowperl 500 29 32 30 I 29 29
between bump
and stop sign
2900blk Cowper I 230* ... ·1 26 31 27 I 27 I 26
between b'impS
---.......... -~----......... -......... -----........ ---........... _-....... _--...
"Source: California Traffic Control Devices Committee, 'Subco~ittee Report on Pave~ent
Undulations', pp, 10, 15. Exp.cted speed depend, on bump spacing.
"*Measurements of speeds may fluctuate up to approximately. or . 3 mph, so changes
of le5$ than 3 mph should not be considered to be particularly meaningful or to b. causad
conclusively by the road bumps.
""In January 1990, this spaCing was reduced to 230 feet from the previous 270 f •• t.
<D
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G> ATTACHMENT 2
MIDTOWN RD.1\Il BUMP .Il£MONSTRAThlll PROJECT
COMI'AA1SOII Of DAILY TRAffIC VOlVMES
... "''''c,.. •• ....; ............... _,.· •• c ...... ''' ............... ''' •• ". ........ ''' ....................... .
lOCATlOfi I ~~~~_~~F~~_V~~~.~:~~~~_~~_~~~~:~~~~~~
I 16 ,,"S
)
BofOre Bumps INid Oemo After Demo After
5/88 1/89 5,89 De"",
(IO/90}
"'=_~Q_~._a ... __ ~_ .. _g •• I~._~~~=~==g ••• _.2 .. ~~=~~ __ ~=.,._=,._ .......... ~ ...
, i Streets with bUlllps:
C """"r between 281~ 1115 1515 1550
Oregon 1 IIarfon (8/89j
Cowper between 2525 la9S 2240 21SO
Colorado. £1 Oorado
f4ariort between 77S 595 650 630
Ta ssO 1 Cowper
Color.do between 2985 2,65 2155 2nO
8yro" I Cowper
----------------------------------------------.---------------------
Streets without buaps:
ColJrado between
Kipling 1 Wayerley
waverley between
Dreg .. , "arion
950 910
1095 895
1010 gao
1135 1085
••
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(;) ~ ~ • ATTACHMENf 3 . ....
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"'J'~_~_. ,.:_,_!... ____ . ___ .
o AT TACHMEffi 4
LEGAL ISSUES P(RTAIN!~G TO ROAD BUMPS
(E<eerpt feom CMR:47Z:9, October 12, 1989).
Consfderatfon of lWhether to install and maintaln road bumps lnvah"es two legal
issues: IIIhethier the City has the legal authority to il'lst.a11 road bumps and the
potEctfal lilbfTitJ of t~e City, or lack th~reof, for injuries relating to roaj
buIops.
legl1 AutMrjty, Section ,1 iOG.l of the Cal ifornia VehftTe Code prohibits cities
frOil instilling any traff1c control dEVice that does not con(o)ll' to the Cal trans
lr.f'1~ J4anl.!a 1 . Therefore, t f road bumDs are c1 ass ifi ed as tra ffi (: control de~ices they are not authorfzed~ Vehic1e'Code Section 440 defines in ·official
traffit contral device-as, ·an~ sign, sig~al, markir.g, or device.~.pTac~d or
erect~.~~for the purpose of re9ulating, w~rn1ngt or guiding traffic, but does
not include isl~ndsJ curbs, traffic barriers cr other roadway design features.
The CTCDC 1 previously mentioned. after lengtny discussion and debate, agreed that
road buaps should be considered r(lad~ai' des1grl features and not troilfflc control
dev1ces. Th~5 chssHfed, the,Y are subJect to local control and not state
preemption .. Tl:;e CTeO( recoomendatiDl ,..:.;). bued en extensive research and
investigation, and the CTeO( is the only technical body to have spo~e, on the
is.$J.!e~ It DUst be kept 1l~ IIIfnd, hO\Jio'ever, that Cal traM lias so far refused te
acknowledge ro.d bumps It .11. Sine< the prl.ary focus of Caltr,ns is traffic
co~trol deY1~es. the cantinufng refusal of Cal trans to classify road bumps as
traffic control deYices qiY~s some weight to the deter.inllfon tnat they are
Tuadway design features. further support for t~is position is found in Sect~on
21l01{f) of the Vehicl. Code, which was enacted In response to the Berkeley
street barricades cas. (Rumford Y. Berkeley, (1982), 3i C.3d 545}, and ohich
specifically recognizes islands, curbs, ~nd traffic barriers as roadway design
features under local contrDl, wtien us.ed to implement the circulation element of
• iener.l plan. Although road bumps are not included i. the Vehicle Code list,
and although the purpose of road bumps is not to prohibit entry to or from
streets (is is the purpose of those listed features). the two types of features
are installed on a pavement and not netessarily is an 1~te9rited part of the
pavellent , and both ~av!! the effect ~f Slowing and diverting traffic~ Therefore,
ilttlougn neither iii court. Caltrans. nor the tE-9is1 ature tlas spoken on ttle
subject j we bel ie\fe that the City Council can reasonably deterlline that reac
bumps are roadway design features and, thus, are under iocal control.
J...ijbilit't rssues. The potential of the road bumps to cause accidents is slight,
as discuss~ elsewhere in this report. Therefert, we do not believe that read
buaps, If properl, Installed and s!g"ed, would be held to constitute. dangerous
condition for which lIability would be attributed to the City. However, If •
court were to find that road bumps did constitute a hazardous condition ana were
the praxillate c.ause of an injury. Se<:t1on a30.6 of tne Cal iforrlh Government Code
would give the City a qualified i..unity from liability, If it were shown that
the City Council .tudied the design and the issu •• regarding implementation and
exercised Its discretionary authority to adopt reasonable standards pursuant to
whIch the bwops were then properly inst.iled.
: ... -' ~ '. , .
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• ATTACHMENT 5 o f
IDENTIFICATIO~ OF EM~RSENCY RESPONSE RdJTES
Tentative Scope of Work
The ccntractor will review and b~come familiar with the 19B~
Ftre Demand Zone Hap for the Pale Alto Fire Oe:~artmer.t service
area, including the desired response time performance standard
by demand ~one.
Zone A z < 4 minut~s
Zone B < 5 ~inutes
Zone C < 8 ninutes
Zone D < lS ~ir.utes
2. The contractor 'Will revi<ew the exie-ting locations of fire
stations and viII identifl~ Primary or Routine EI:Iergency
Response routes into all fir~ demand zones ar.d ~ill include
those routes in the Fire Departm~nt's digital mapping system.
The contractor will d~velop the criteria used for identifying
what is a primary emergency response route in conjunction 'With
the Fire, Public works, and Planning Departments.
J. The. contractor will identify on that map all non-temporary
obstacles to emergency responses in all fire demand zon~s ..
includinq, but not limited to:
(4) traffic barriers:
(b) ~oad closure6~
ee) road bwops,
(d) unique access problems~
4~ Tha contractor will evaluate the effect that those obstacles
will have on the desired response time perfonnance standard by
delDand zone. and will identify all obstacles which would
negatively iapact those times.
RG:cs
11/15/90
No
No
No
HO_===r-__ ..j
No
yes
Report to CDuncil
Refer to P ana P
\
.f.tll!t.iliML9_f Ba sic Crj ter i a:
-leCil resident~al street
-speed limit 2S mp~ or les~
-logical sogment; SOO fe.t to "n"polnt
··not a trl,} ~k.. bl1s or primary emergency r<lute
-rad~ not to exceed 5 percent
fuluiltion QL.r~eighborho?d Criteriq";
-1/3 of resid'nts of str •• t sign petltlon
valuation of Operatjonal Criter~a:
-B5t~ percentile speed 35 mp~ or more
-AnT bet.een 500 .nd 4000 v.~icl.s
-6 or D".ore :speed rel ated accidents in preceding
three yearL
Determination of Bump locatjons:
-nu.ber .nd loc.tion of bumps
-traffic diversi~n i~ .!t'gation st~dy
-neighborhood ~.t;ng
-staff recommendatlon
FUNDING PROCESS;
\ Yes ..
Imp 1 emt!nt at; on
o
ATTACHMENT 7
f>ALO ALTO
ST~E:e.1 NE.TWO~K
---CO\..LI!.C TO~
---..... "'T£;"" .... L
___ !E.lf-PP<!iSSWAY
FPle.E.WAY
• INT~"'C 1-<AN6E
.'?'",' PL.~N'NG AP-E .....
aoUNt::>_y
o ATTACHMENT 8
PROCEDURES AND GUiDELINES FOR APPLICATION AND DESIGN OF ROAD BUMPS
IN PALO ALTO j
A. AdministratiVe Procedures
1. A request tor road bumps must originate from a resident of the
street on which the bump is desired. -:'hat request may bE
forwarded through the neighborhood association representing
that Area .. Alternatively, staff may suggest to a resident who
haa filed a complaint relating tQ his or her street that road
bumps BaY be an option for addressing the complaint (in which
case the next step Would be skipped).
2. After receipt of a reql.lest, staff will detena.ine. if the street
aeets the Basic Criteria listed in section 5. If the street
dQes not meet the Basic Criteria, staff wi 11 so inforJI the
requestor in writi"9,. and advise the Police Department that a
speed complaint bas been received th~t aay need enforcement
action.
3. It the street aoes lIeet the Basic criteri.a,. the requestor will
be required to submit a petition (forma. provided by the City)
wbich establishes the extent of nei.ghborhood support ,tvo
thirds, as explained in section BJ~
4. After staff receives and verifies the petition, staff will
qather traffic data in order to dete~ine if the street meets
the Operational Criteria list.ed in saction B. If the street
does not meet the Operational Criteria, staff will 80 inform
the requestor in writinq, and advise the Police Depar+ ..... ent·
that a speed complaint has been received th.at may need
enforcement action.
5. If the street Ile;ete all the criteria listed
statf will con~~ elmore thorough evaluation ...
a. Number and' lJlation of potential road
eliqible street will be determined.
in Section B,
includinCj;
bumps on the
b. The extent cf the area ~here traffic diversion .ight
occur will be determined. The amount of tratfic
diversion from the eligible (~priuary·J street to other
{-secondary1ll J streets in this area will be estiaated.
Traffi~ speed and volume data on these 'secondary streets
will be Follected.
c. If neceS'5ary, mitigation measures for the secondary
streets will be proposed. If road bumps are proposed as
aitigation measures, the secondary streets shall meet as
li1any of the eligibility criteria listed in Section B as
possible ...
•
d. A neighborhood meeting for residents of the primary and
secondary streets will be held~
e. A to.port. for City council will be prepared. It Is
~ anticipated that this report would be referred to the
Policy and Procedures CQmmitte~.
6. After" Pol icy and Procedures Committee review, the request will
be forwarded to the cjty Council for program, but not fundinq.
approval.
7. If City Council approves the road hump request., the project
will be ccnsidered for fundi~~ approval by inclusion in the
capital Improvement Program (CIP) screening process which
normally begins in December ot each year.
a. If approved durir~ thf! scree.ning process., the road J)ump
project will be incl~ded in the elP which the city Hanaqer
recommends to the city Council. In Kay of each year, the
recollUlended C.IP is transmi't.ted to the city council for
consideration and approval., via public hearinga be:fore the
Finance and PUblic Works Co~.ittee~ (Note that a road bump
project IlAY aeet all criteria a . .,d guidelines, b'.lt could still
fail to receive fundinq approval in the CIP.)
9. Road bumps may be cons1.dered .for reJlOval under a similar
procedure.
e. CTitar$a tor Determination of Eligible street segnents,
A street seqaent (·stre.et") is el 19' ible for road buaps it All of
the ~ollowing criteria are met.
o Basic Criteria
o Neighborhood Support Criterion
o Operational Criteria
Basic Criteria
1. The street Is a local &tre~t as defined by the Palo Alto
Comp~ensive Plan, and is predominantly residential.
2. The prima facie or posted speed limit is 25 mph or less.
3. The segment :.\1st begin and end at logical points such as
arterial and collector streets, sbarp curves, jogs, cul-de
sacs, or or other discontinuities. The seqment must be long
Guidelines
November 14, 1990
page 2
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enouqh that .et lea.t on~ bump can be installed which meets the
diatanca raquireltents of :.Section D, ite. 2 (qenerally 800-1000
teet 1,,"9). I
4. The street is net a desiqnat6d truck or transit bus route or
a pri.ary or ro~tine access route for emerqency v~hicles.
5. The grade does not exceed five percent.
• Neighborhood support Criterion
1. OCcupants of at least two-thirds of all dwellings with
addresses en the .. treet 'Where b\UlPs are request.ed to };Ie
locatsc! "iqn a pet! Hon nquesUng the bUllps.
operatiooal Cliteria
1. The average daily traffic (ADT) is bet-ween 50C and COOO
vehicles ..
2. The ~verage prevailin9 85th percentile apeed is a aini~uD of
35 mph.
3. At least six reported speed-related traffic accidents have
occurred in the l ... ~iatoly preceding three conse.cutive years.
c, Ipgation of Road Bumps
1. Tbe m.iniaWl. distance fro. an intersection to a road bump,
where the street with the bump is a through street with no
stop sign, shall range from 50 to 200 feet, depending on the
type ot intersection.
2. A bump shall not be installed within a sharp horizontal curve
{gene.rally a curve of less than 100 feet ee:nte'["lin~ radius) or
within 100 feet of the beqinninq or end of such a curve.
J~ The first bump at either end of a series shall be placed such
that a. warning sign can be installed be.tore the bump at a
distance equal to at least the .iniJlUIl safe stoppinq distance,
based on the prevailinq 85th percentile speed.
4.., Any bump shall be viaible. to oncoming traff~c for at l.east the
.inimua safe stoppinq distance, based onithe prevailing or
expected 85th percentile speed.
Guidelines
November 14, 1990
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page 3
•
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5~ A bu.p ahall not be placed ever manholes, catch basins, or
other utility access points~
6 ~ A bump shall only be leeatad ""here it does not cause ~
substantial adverse impac't on established drainage patterns ..
1. A bump shall only' be loca.te:i 'Whert! a curb, pole, tree, or
o~er obstruction {existing or new) would block traffic from
~rivinq around the end of the bumpa
8. The following quidelines should a~ply ~here feasible.
a. Road bumps should te placed near streetligbts.
b. Road bumps should not be loc~ted immediately adjacent to
driveways.
CoO Road bumps and related signing should be located on
property lines... and ",here shrubbery, fences or other
obstructions interfere ~ith the dir&ct viev of the bumps
from residences~
Dr Design of Road Bumps
1~ A road bump shall be three inches high at its .idpoint
(tolerance o.f -0,. +-0.25 inches) I and 12 feet wide in the
direction of travel, as shown in Exhibit B.
2. The distance between road bumps or between a road bump and a
stop I!!IIlgn, sharp curve, jog, cul-de-sac., or other
discontinuity which reduces speed to approximately is mph,
shall be 500 feet ,(tolerance of -100, +50 feet}.
:J.. Signing and striping shall be in accordance with Exhibits A
and C.
Attachaents: EXhibits A, S, C.
Guidelines
Noveabe!' 14, 1990
paqe ..
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rt. OF STREET ....
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CURB,GUT7EfI .. SIOewAL.1(
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EDGE OF PAVEMENT 01'1 auTTt:R LlP-,
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_~ WHITE F'''''I::MENT MARKING --
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[ PROPEO,.. LINE
~...--W31 & we SIGNS
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B
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fil6I'L'~ '1'111 ""V.MI!HT MARIlER.
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50'
Wll & W" SIGNS r--
_DIM'""O.' Allla 'CMII ID-'OOT WIDTH I." •••• OUTT."',.
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SPEED BUMP Q~TAIL
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EXHIBIT A
<:!' AEFLe:CTIVE WHITE STRIPE {"TYPICALl
~OG~ 0" PAvEMENT OR GUTTEA UP
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BItCK OF CURS 3 GUTTER
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CUIIIB,GIJT'rER &. SIDEW .... LK -'\
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CONCRETE SIDEWALK -.
CONCRETE -
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EXHIBIT C
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;"OlAM£TER1
TYPU;.A4 WARNING SIGN /.NSTAUATION.
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TYP.!£A.J".I'{JljlNING SIG!! INSIALLATION
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