8/8/2019 Pages From Design Criteria - Medians

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JUNE2009 REVISIONNO.02 ROADWAY 832

Controldrainage Restrictvehiclestothepavementarea

Define

points

of

access

to

abutting

properties

Verticalcurbsshouldnotbeusedonhighwayswithdesignspeedsofmorethan70km/h. Ifacurbis

necessaryinthiscase,acurbclearanceof0.6mshouldbeaddedtotheoutsidelaneadjacenttocurbed

edges. Wherethereisashoulder,thereisnoneedtoprovideacurbclearance.

8.7.5 Borders,BufferStripsandSidewalksTheborderistheareaactingasabufferzonebetweentheedgeofpavementandtherightofwayline.

Borderareasseparatethetrafficfrompropertiesabuttingtheroadorhighway. Onsomeroads,

sidewalksareincludedwithintheborderlimits. Inthosecases,aminimum600mmbufferstrip

separatingthesidewalkfromthecurbisdesirable,providedsufficientrightofwayisavailable.

Bordersare

capable

of

accommodating

road

signs

and

structures,

traffic

control

devices,

traffic

signals,

utilities,lightingandlandscapingfeatures. Thepreferredlocationfortheseappurtenances(utilitypoles,

firehydrants,lighting,andtrafficcontrolboxes)isbeyondthebackofthesidewalk,especiallywhena

travellaneisimmediatelyadjacenttothecurb.

Sidewalksareprovidedwheretheyarejustifiedbypedestrianactivity. Sidewalkwidthvariesaccording

toprojecteduseandavailablerightofway,with2.0mpreferred. Incommerciallydevelopedareas,the

entireareabetweenthecurbandbuildingsisoftenusedasapavedsidewalk.

8.7.6 MediansMediansareusedtoseparateopposingtrafficlanesonmultilaneroads. Amedianwillprovidemanyor

allofthefollowingbenefits:

Separationfromopposingtrafficreducingthelikelihoodofaccidentsandimprovingthetrafficflowcharacteristics.

Refugeforemergencystops Areaforcontroloferrantvehicles Reductioninheadlightglare AreafordecelerationandstorageofmainlineleftturningandUturningvehicles Areaforstorageofvehiclescrossingthemainlineatintersection.

Area

for

placement

of

luminaire

supports,

traffic

signs,

traffic

signals,

guardrail,

landscaping,

and

bridgepiers.

Increaseddrainagecollectionarea Refugeareaforpedestriansandbicyclists. AreaforfutureadditionallanesMediansmayrangeinwidthfromaslittleas1.2minanurbanareato20mormoreinruralareas.

Medianwidthwilldependonthefollowing:

Functionalclass

8/8/2019 Pages From Design Criteria - Medians

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JUNE2009 REVISIONNO.02 ROADWAY 833

Typeofmedian Rightofwayavailable Trafficoperationsatcrossingintersections SafetyItisrecommendedthaturbanmediansbecurbed. Ruralmediansshouldbeprovidedwitha0.60mor

1.22mshoulderandnotcurbed;adepressedmedianispreferredtoimprovedrainage. Acurbed

median,however,isdesirablewherethereisaneedtocontrolleftturnmovementsandwhenthe

medianistobelandscaped. Ifthemedianiscurbedandpaved,themediansurfaceshouldbedesigned

tohaveslopesof2percent,andshouldfallawayfromthecenterofthemedian. Nonpavedmedians

shouldbedepressedandslopetowardstheinsideat1V:6Hforproperdrainage,butconsideration

shouldbegiventoadditionalstoragecapacityoroutletsforstormconditions. Pavedmediansmay

requireincorporatingdrainagesystemssuchasmanholes,culverts,etc. Alldrainageinletsinthe

medianshouldbedesignedwiththetopflushwiththegroundandsafetygratingsforculvertends.

Table822setsouttheminimumwidthsforcertainfunctionalrequirementsofmedians.

Table822. MinimumMedianWidthsforCertainFunctions(m)

RequirementsAtSignalized

IntersectionsElsewhere

Minimumtoaccommodatesignalheads 1.2to1.6

Minimumcurbedtoseparatetraffic 1 1

Minimumtoaccommodatepedestrians 2.0to3.5 3.5

Minimumtoprovideleftturnlanes 4.2 4.75

MinimumtoprovideUturn n/a 5.0

Minimumforlandscapingprovision n/a 8

Table823providesthetypicalmedianwidthsbasedonroadwayclassifications.

Table823. TypicalMedianWidths(m)

RoadwayClassificationUrban Rural

Min. Desirable Min. Desirable

FreewaysandExpressways 6.0 8.0to10.0 6.0 8.0to10.0

PrimaryArterials 6.0 8.0to10.0 6.0 8.0to10.0*

SecondaryArterials 4.0 6.0 4.0 12.1*

Collectors 2.0 6.0 4.0 6.0

* Considerationforfuturelanewidening