Traffic Calming:Traffic Calming:
Introduction and ApplicationsIntroduction and ApplicationsJune 21st, 2007June 21st, 2007
bybyIndraneel Kumar, AICPIndraneel Kumar, AICP
Transportation Planning and Traffic Transportation Planning and Traffic Calming- Part 2Calming- Part 2
• 3 Es- Education, Enforcement, and Engineering
• Police enforcement-engineering options- street closure
• Management of traffic by volume and speed
• Part of “Context Sensitive Design”
• Flexible design standards
IntroductionIntroduction
What is Traffic Calming?What is Traffic Calming?
Several definitions- ITE, VTPI,
Source: VTPI.org
HistoryHistory• 1960s first experiment commenced in Holland
• 1970s- Implementation in Germany (Verkehrsberuhigung or Transportation Calming)
• 1980s- Livable Streets by Appleyard, UC Berkeley
• Institute of Transportation Engineer’s Guidebook
• 1990s- Traffic Calming: State of the Practice, Reid Ewing, ITE
• Thousands of Traffic Calming projects
Control Speed; Control Volume; Control Volume / SpeedControl Speed; Control Volume; Control Volume / Speed
Applications: Traffic Calming to Control SpeedApplications: Traffic Calming to Control Speed
Bulb-Outs/Bulb-Outs/
Curb Extensions/Curb Extensions/
NeckdownsNeckdowns
• Bulbs, Chokers, Neckdowns are Bulbs, Chokers, Neckdowns are interchangeable termsinterchangeable terms
• Extension of the curb and Extension of the curb and sidewalk to narrow the roadwaysidewalk to narrow the roadway
• Physical constraintPhysical constraint
• Visual traffic calming effectsVisual traffic calming effects
• Pedestrian crossing Pedestrian crossing
Source: www.pedbikeimages.org / Dan Burden
Source: www.pedbikeimages.org / Dan Burden
Bulb-OutBulb-Out
• Extension of the curb and Extension of the curb and plantingplanting
• Midblock or intersection Midblock or intersection cornerscorners
• Parallel, angled chokers, etc.Parallel, angled chokers, etc.
• Planting to alert the motoristPlanting to alert the motorist
• Physical constraintPhysical constraint
• Visual traffic calming effectsVisual traffic calming effects
Source: Making Streets That Work
ChokerChoker
Applications: Traffic Calming to Control SpeedApplications: Traffic Calming to Control Speed
ChokersChokers
Source: www.pedbikeimages.org / Dan Burden
Source: www.pedbikeimages.org / Michael King
Applications: Traffic Calming to Control SpeedApplications: Traffic Calming to Control Speed
• Chicanes- staggered curves Chicanes- staggered curves
• Alternate extension of the curbAlternate extension of the curb
• Shift in alignmentShift in alignment
• Physical constraintPhysical constraint
• Visual traffic calming effectsVisual traffic calming effectsChicanesChicanes Source: ITE
Source: www.pedbikeimages.org / Michael King
Source: www.pedbikeimages.org / Portland
Source: www.pedbikeimages.org / Portland Office of Transportation
Applications: Traffic Calming to Control SpeedApplications: Traffic Calming to Control Speed
Speed Tables, and CushionsSpeed Tables, and CushionsSource: www.pedbikeimages.org / Dan Burden
Source: www.pedbikeimages.org / Mark Lavergne
Source: www.pedbikeimages.org / Michael King
• Cushions- Convenient for Cushions- Convenient for emergency vehiclesemergency vehicles
Applications: Traffic Calming to Control SpeedApplications: Traffic Calming to Control Speed
Speed Bumps and HumpsSpeed Bumps and Humps
Source: PCRD / Kumar
Source: PCRD / Kumar
Curb Radius, Raised Crossings and IntersectionsCurb Radius, Raised Crossings and IntersectionsSource: www.pedbikeimages.org / City of Portland
Source: www.pedbikeimages.org / Dan Burden Source: www.pedbikeimages.org / Peter Lagerway
Applications: Traffic Calming to Control SpeedApplications: Traffic Calming to Control Speed
• Tighter curb radius Tighter curb radius
• Raised crossing and Raised crossing and intersection- alerts driversintersection- alerts drivers
• Paving treatment + Raised Paving treatment + Raised surfacessurfaces
• Visual traffic calming effectsVisual traffic calming effects
Applications: Traffic Calming to Control SpeedApplications: Traffic Calming to Control Speed
Paving TreatmentsPaving Treatments
Source: www.pedbikeimages.org / Dan Burden
Source: www.pedbikeimages.org / Dan Burden
Source: www.pedbikeimages.org / Dan Burden
• Delineate users Delineate users
• Visual traffic calming effectsVisual traffic calming effects
Applications: Traffic Calming to Control SpeedApplications: Traffic Calming to Control Speed
Paving TreatmentsPaving TreatmentsSource: PCRD / Kumar
Source: www.pedbikeimages.org / Dan Burden
• Delineate the edge Delineate the edge
• ADA GuidelinesADA Guidelines
• Visual traffic calming effectsVisual traffic calming effects
Applications: Traffic Calming to Control VolumeApplications: Traffic Calming to Control Volume
Diverters, Partial Street ClosuresDiverters, Partial Street Closures
Source: www.pedbikeimages.org / Dan Burden Source: www.pedbikeimages.org / Dan Burden
• Diagonal diverters create two Diagonal diverters create two unconnected streets- unconnected streets- intersection intersection
• Partial closure for motorized Partial closure for motorized traffic traffic
Source: Delaware DOT
Applications: Traffic Calming to Control VolumeApplications: Traffic Calming to Control Volume
Full Street ClosuresFull Street Closures
• Full closures- reroute Full closures- reroute the trafficthe traffic
• Partial/ Full closures Partial/ Full closures and diverters are used to and diverters are used to retrofit neighborhoods retrofit neighborhoods for traffic calmingfor traffic calming
Source: PCRD / Kumar
Gateways, Lane ReductionGateways, Lane Reduction
Applications: Traffic Calming to Control Volume/SpeedApplications: Traffic Calming to Control Volume/Speed
Source: www.pedbikeimages.org / Dan Burden
Source: www.pedbikeimages.org / Michael Cynecki
• Lane reduction is also Lane reduction is also known as road diets; lane known as road diets; lane narrowing- visual traffic narrowing- visual traffic calmingcalming
• Gateways- visual traffic Gateways- visual traffic calmingcalming
Source: PCRD / Kumar
Refuge Islands, Roundabouts / Traffic CirclesRefuge Islands, Roundabouts / Traffic Circles
Applications: Traffic Calming to Control Volume/SpeedApplications: Traffic Calming to Control Volume/Speed
Source: www.pedbikeimages.org / Dan Burden
Source: www.pedbikeimages.org / Dan Burden
• Roundabouts are Roundabouts are popular techniquespopular techniques
• Comprehensive traffic Comprehensive traffic management plan / management plan / retrofitretrofit
Applications: Traffic CalmingApplications: Traffic Calming
Traditional Neighborhood / Narrow StreetsTraditional Neighborhood / Narrow Streets
• Congress for the New UrbanismCongress for the New Urbanism
• Wider street standards are giving Wider street standards are giving way to narrower streets, way to narrower streets, particularly in residential areasparticularly in residential areas
• More asphalt = More vehiclesMore asphalt = More vehiclesSource: www.pedbikeimages.org / Dan Burden
• A grassroots effort for A grassroots effort for narrow street standards narrow street standards is happeningis happening
Source: FHWA
Applications: Traffic Calming- Streets for Living Applications: Traffic Calming- Streets for Living
WoonerfWoonerf
• Streets designed to be Streets designed to be shared by pedestrians, shared by pedestrians, motorists, and the community motorists, and the community
• Sidewalks, planters, Sidewalks, planters, benches are merged into the benches are merged into the streetstreet
• Physical constraints Physical constraints
• Speed < 10 miles per hour Speed < 10 miles per hour
• Public realm Public realm
• Higher costs Higher costs
• Emergency vehicles ?Emergency vehicles ?
Source: Maricopa County Government
Travel Impacts-Travel Impacts-
• Pre and post Traffic Calming Pre and post Traffic Calming travel impacts- motorized / non travel impacts- motorized / non motorized travelmotorized travel
• Assumption- 10-20 % increase Assumption- 10-20 % increase in non motorized travel- half of in non motorized travel- half of that substitute motorized travel that substitute motorized travel
Traffic Calming Impacts- Benefits and Costs Traffic Calming Impacts- Benefits and Costs
Advocates- Advocates-
• Traffic Calming protects Traffic Calming protects residents, bicyclists, and residents, bicyclists, and pedestrianspedestrians
• Multiple and safe use of Multiple and safe use of the street the street
Critics-Critics-
• Waste of resourcesWaste of resources
• Shifts the traffic Shifts the traffic problems from one to problems from one to another streetanother street
Source: Todd Litman; Traffic Calming: Benefits, Costs, and Equity Impacts; www.VTPI.org; Calgary health region
Traffic Calming Impacts- Benefits Traffic Calming Impacts- Benefits • Increased SafetyIncreased Safety
# Significant reduction # Significant reduction in accidentsin accidents
# Payback through lives, # Payback through lives, injuries, and insurance injuries, and insurance savingssavings• Increased non Increased non motorized and motorized and decreased decreased motorized travelmotorized travel
# Less noise and # Less noise and air pollution; air pollution; health benefits; health benefits; parking & gas parking & gas savings, etc. savings, etc.
Source: Todd Litman; Traffic Calming: Benefits, Costs, and Equity Impacts; www.VTPI.org
FatalFatal
Traffic Calming Impacts- Benefits and Costs Traffic Calming Impacts- Benefits and Costs
Benefits….. Benefits…..
•Increased public realm, Increased public realm, interaction and crime interaction and crime prevention- Crime prevention- Crime Prevention Through Prevention Through Environmental Design Environmental Design (CPTED)(CPTED)
• Defensible Space by Defensible Space by Oscar NewmanOscar Newman
• Increased property Increased property values values
Source: Todd Litman; Traffic Calming: Benefits, Costs, and Equity Impacts; www.VTPI.org
CostsCosts
• Project expensesProject expenses
• Liability claimsLiability claims
• Vehicle delaysVehicle delays
• Traffic spill to other Traffic spill to other roadsroads
• Problems for Problems for emergency and emergency and service vehiclesservice vehicles
• Driver frustrationDriver frustration
• Problems for Problems for bicyclists and visually bicyclists and visually impaired impaired
Traffic Calming Impacts- Horizontal vs. Vertical Equity Traffic Calming Impacts- Horizontal vs. Vertical Equity
• Equity is important in Equity is important in Transportation PlanningTransportation Planning
• Horizontal equity is distribution of Horizontal equity is distribution of benefits and costs within groups benefits and costs within groups similar in income, wealth, and abilitysimilar in income, wealth, and ability
• Vertical equity is distribution of Vertical equity is distribution of benefits and costs within groups benefits and costs within groups dissimilar in income, wealth, and dissimilar in income, wealth, and abilityability
• A better balancing of different A better balancing of different uses of the street- motorists, uses of the street- motorists, cyclists, pedestrians, residentscyclists, pedestrians, residents
• Increased safety for pedestrians, Increased safety for pedestrians, cyclists, residents, and transit userscyclists, residents, and transit users
Source: Todd Litman; Traffic Calming: Benefits, Costs, and Equity Impacts; www.VTPI.org
Traffic Calming – Planning Process Traffic Calming – Planning Process
• Public / residents must be involved Public / residents must be involved from the beginning (neighborhood-wide from the beginning (neighborhood-wide traffic management)traffic management)
• Residents petition for traffic calming Residents petition for traffic calming (street-wide)(street-wide)
• Public Works or Engineering Public Works or Engineering Department propose- traffic calming Department propose- traffic calming strategies and devicesstrategies and devices
• Community acceptance is essentialCommunity acceptance is essential
• Traffic calming device is put on placeTraffic calming device is put on place
• Project evaluationProject evaluation
• Traffic calming device is made Traffic calming device is made permanentpermanent
Traffic Calming- SourcesTraffic Calming- Sources
www.VTPI.org
www.ITE.org (Traffic Calming: State of the Practice)www.ITE.org (Traffic Calming: State of the Practice)
www.PBIC.org
www.PPS.org
www.TrafficCalming.org
http://www.fhwa.dot.gov/environment/tcalm/index.htm http://www.fhwa.dot.gov/environment/tcalm/index.htm
www.planning.org (Traffic Calming: PAS 456) www.planning.org (Traffic Calming: PAS 456)
http://www.io.com/~bumper/ada.htm http://www.io.com/~bumper/ada.htm