Traffic Calming

Topics

• Introduction andPurpose
• Traffic CalmingTreatments
• TrafficCalmingImpactsAssessment

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Traffic CalmingDefinition

Traffic calming involves changes in street alignment, installation of barriers, and other physicalmeasurestoreducetrafficspeedsand/or cut‐throughvolumesintheinterestofstreetsafety, livability,andotherpublicpurposes.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

GoalsofTraffic Calming

 

• Improvedqualityoflife
• Incorporationofthepreferencesandrequirementsof the people using the area along streets, or at intersections
• Creationofsafeandattractivestreets
• Reductionofthenegativeeffectsofmotorvehicleson theenvironment
• Promotionofpedestrian,cycle,transituse.

 

 

 

 

 

 

 

 

 

 

 

 

HistoryofTraffic Calming

• InternationalOrigins
  • DutchWoonervenandOtherExperiments
  • DanishEnvironmentallyAdaptedThrough‐Roads
  • GermanArea‐wideTrafficCalming
  • BritishEnvironmentalTrafficManagement
  • AustralianLocalAreaTrafficManagement

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OverviewofCurrentPractice

• Hundreds ofPrograms

 

• GrowingInterestAmongTransportation Professionals

 

• Someissuesofconcernarestillrelevant

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Traffic Calming

Topics

• Introduction andPurpose
• Traffic CalmingTreatments
• TrafficCalmingImpactsAssessment

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Traffic CalmingTechniques‐1

• Raised pavementareas
• Reduced streetareas
• Streetclosures
• Trafficdiversion
• Textureandvisualdevices
• Parking

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Traffic CalmingTechniques‐2

• CombinationDevices
  • Woonerf
  • Entrytreatments
  • Sharedsurfaces
  • Bicycleboulevards
  • Channelization
  • Trafficcalmingonmajorroads
  • Modified intersectiondesign

 

 

 

 

 

 

 

 

 

 

 

 

 

Choosing the RightTools

• Identifyingthenatureandextentoftraffic‐related problemsonagivenstreetoringivenarea
• Selecting and implementingcost‐effective measuresfor

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Traffic CalmingTreatments

1. High vehicle speed trafficcalming treatments
2. Hightrafficvolumecontroltreatments
3. Pedestriansafetyenhancementtreatments
4. Bicycle accommodations contributing to trafficcalming

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AddressingHighSpeed:NarrowTravelLanes

Treatment:

Restripingofexistingtravellanestoreducewidth.

 

 

 

 

 

 

 

 

 

 

 

AddressingHighSpeed:On‐StreetParking

Treatment:

Full‐time parking provided adjacent to the curb or just beyondabufferedbicyclezone (protectedbicyclelanes).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AddressingHighSpeed:RumbleStrips

Treatment:

Pavement surface treatments intended to cause vehicle vibrations signalingdriverstoslowdown.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AddressingHighSpeed:SpeedBumps/Humps

Treatment:

• Speedbumpsarenarrow,mountable obstructions installed on the pavement surface across travel lanes,intendedtocausevehiclesto slowtoalmostafull
• Speedhumpsareflatterandwider, creating a gentler crossing by

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Speed HumpTypes

Prefabricated humps

22’ parabolic hump ‐‐ Ft. Lauderdale

 

30’ circular hump ‐‐ Beaverton, OR

 

 

 

 

 

 

 

 

 

 

 

ITESpeed Hump Guidelines

• Streets classified as”local”
• No more than 2 travel lanes or 40 foot pavementwidth
• Horizontal curve of 300 foot radius ormore
• Vertical curve with adequate stopping sightdistance
• Grade of 8 percent orless
• Posted speed limit of 30 mph orless
• No more than 5 percent long wheel-basevehicles
• Not on primary emergency response route or busroute
• Majority of residentssupport

 

 

 

 

 

 

 

 

 

 

 

 

AddressingHighSpeed:SpeedTable

Treatment:

• Speedtablesaresimilartospeedhumps excepttheyhaveaflat‐top.

 

• Generally wider than speed humps, gentleronvehicles,andtypicallyusedon higher‐orderroadsbecausetheyallowa

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AddressingHighSpeed:RaisedIntersection

Treatment:

• Theentireareaofanintersectionis raised above normal pavement surfacelevel

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AddressingHighSpeed:Chicane

Treatment:

• Aseriesoffixedobjects,thataltera straight roadway into a zigzag or serpentinepath
• Canalsobecreatedbyalternatingon‐ streetparkingbetweensidesofstreet

 

 

 

 

 

 

 

 

AddressingHighSpeed:Chocker

Treatment:

• Narrowingofastreet,oftenmid‐block andsometimesnearanintersection throughcurbextensions,landscaping

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AddressingHighSpeed:Mini‐TrafficCircles

Treatment:

• Asmallcircularoroblongisland usedinthemiddleofintersections andintendedtoforcevehicular traffic to slow and negotiate aroundit.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AccommodatingLargeVehiclesatMini‐TrafficCircles

 

 

 

 

 

 

 

 

 

 

 

AddressingHighVolume:HalfClosure/ Semi‐diverter

Treatment:

• Half Closure/Semi‐diverters use barriers that block travel in one directionforashortdistanceonatwo‐ way

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AddressingHighVolume:DiagonalDiverter

 

Treatment:

• Barrier dividers placed diagonally connectingtwooppositecurbswithin the intersection, blocking through movementsandcreatingtwoL‐shaped street

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AddressingHighVolume:FullStreetClosure

 

Treatment:

Barriersplacedacrossanentirewidthofa street to completely close the street to through‐traffic,usuallyleavingfullpedestrian and bicycleaccess.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AddressingHighVolume:MedianBarriers

 

Treatment:

• Islands are constructed between travel lanesthroughanintersectiontoblock
• Median barriers are intended to preventleftturnsfromthemajorstreet and through movements along the minorstreet.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AddressingPedSafety:ModifyExistingGeometry

 

Treatments:

Modify existing intersection geometry:

• Reducing pedestrian crossing exposure totrafficandincreasingvisibility
• Addingoreliminatingatraffic movement

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AddressingPedSafety:Example:CenterIslands&Medians

 

 

 

 

 

 

 

 

 

 

AddressingPedSafety:TrafficControl

Treatments:

• In‐Street“YieldforPedestrian”Sign
• ProhibitRight‐TurnsonRed
• Signal‐TimingModification
• Leading PedestrianInterval
• Push ButtonRetrofit
• Pedestrian CountdownSignal
• ProtectedLeft‐Turn

 

 

 

 

 

 

 

 

 

 

 

 

 

BikeAccommodations:TrafficControl

 

Treatments:

• Bicycle Sharrows/Enhanced Sharrows
• Bike LaneMarkings
• BikeBox
• Bicycle‐ActuatedSignals

 

 

 

 

 

 

 

BikeAccommodations:GeometricDesign

 

Treatments:

• BicycleBoulevard/Greenway
• MultiusePathway
• Protected BikeLane

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Traffic CalmingOptions

 

 

 

 

 

 

 

 

 

 

 

TrafficCalmingGuidelinesforOldandNewStreets

Source: City of Eugene, Eugene Local Street Plan p. 71.

 

 

 

 

 

 

 

 

 

MUTCDOperationalGuidanceforTrafficControl

• Yellowdiamond‐shapedsignsforwarning
• Yellowlinesseparatingopposingtraffic
• Letteringorsymbolsofadequatesize
• Symbolsinpreferencetowordmessages
• Advancewarningwhenhighdriverjudgmentor decelerationtoaspecificspeedisrequired
• Size,height,position,lettering,and reflectorizationperMUTCD

 

 

 

 

 

 

 

 

 

 

 

TrafficCalmingTreatmentsStandardCostEstimates

 

 

 

 

 

 

 

 

 

 

 

Traffic CalmingCombinedMeasures

 

 

 

 

 

 

 

 

 

 

Traffic Calming

Topics

• Introduction andPurpose
• Traffic CalmingTreatments
• TrafficCalmingImpactsAssessment

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SpeedandVolumeImpacts‐‐SomewhatPredictable

 

 

 

 

 

38 -> 23mph

224 -> 92vpd

40 ->37 mph

13,000 ->10,300vpd

 

 

 

 

 

 

 

 

 

 

 

 

 

SpeedsImpactsofTrafficCalmingMeasures

85th Percentile Speed Changes (before and after)

 

Treatment         No.of      85%Percentile   Change inSpeed
	Sites	Speed	mph	%
12′ Humps	179	27.4 mph	‐7.6 mph	‐22%
14′ Humps	15	25.6	‐7.7	‐23
22′ Tables	58	30.1	‐6.6	‐18
Circles	45	30.3	‐3.9	‐11
Narrowings	7	32.3	‐2.6	‐ 4
Half Closures	16	26.3	‐6.0	‐19
Diverters	10	27.9	‐1.4	‐ 4

 

 

 

 

 

 

 

 

VolumeImpactsofTrafficCalmingMeasures

 

 

 

 

 

 

 

 

 

 

 

AvgReductioninCollisionsbyMeasure(International)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Source: E. Geddes et al., Safety Benefits of Traffic Calming, Insurance Corporation of British Columbia, Vancouver, 1996, p. 38.

 

 

 

 

 

 

 

 

SafetyImpactsofTrafficCalmingMeasures (U.S. Experience)

 

No.                     Avg.AnnualCollisions                           Sig.

Measure	Sites	Before	After	Change	Level
12’Humps	50	2.6	2.3	-13%	.40
14’ Humps	5	4.4	2.6	-40%	.18
22’ Tables	8	6.7	3.7	-45%	<.01
All Circles	130	2.2	0.6	-71%	<.01
Overall	163	2.5	1.2	-51%	<.01

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EuropeanImpactsofTrafficCalmingonBicycling&Walking

 

 

 

4,500

4,000

3,500

3,000

2,500

2,000

1,500

1,000

500

0

MotorVehicles            Bicyclists              Pedestrians

 

 

 

 

 

 

 

 

 

 

 

ModeShiftsasaResultofTrafficCalming‐Berkeley

 

 

 

600

 

500

 

400

 

300

 

200

 

100

 

0

MotorVehicles                         Bicyclists                            Pedestrians

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Other Impacts

• EnergyConsumption
• AirPollution
• NeighborlinessandSenseofCommunity
• ResidentialSatisfaction
• RetailTrade
• Real EstateValues

 

• EmergencyResponse
• WinterMaintenance

 

 

 

 

 

 

 

 

StrategiesUsedtoAddressFire‐Rescue’sConcerns

• AvoidanceofEmergencyResponseRoutes
• AvoidanceofEmergencyResponseFacilities
• GradualEscalationofTrafficCalmingMeasures
• Communication
• UseofMeasuresthatAccommodateFire‐RescueVehicles
• RedesignofTrafficCalmingMeasures
• AppealforCitizenSupport

 

 

 

 

 

 

 

 

 

 

 

 

WinterMaintenanceApproachonTrafficCalmedStreets

• Familiarizingpersonnelwithsnowplowroutes
• Markingtrafficcalmingmeasurestoletplowoperators knowexactlywheretheyare
• Usingappropriateequipment,suchasrubber‐tipped snowplowblades
• Applyingsaltandsandtoresidualsnow

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Readings

• FHWACourse,11,pp.11‐1to11‐23

 

 

 

https://safety.fhwa.dot.gov/ped_bike/univcourse/pdf/swless124.pdf

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Final Thought

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

West PalmBeach