Traffic Calming State of the Practice Slide Seminar

Session 2: Toolbox of Traffic Calming Measures

Toolbox of Traffic Calming Measures

A Matter of Choosing the Right Tools

Full Closures (cul-de-sacs, dead ends)

Least to Most Permeable

Full Closure for Crime Prevention Only

Half Closures (partial closures, one-way closures,directional closures)

Canadian Design Half Closure/Semi-Diverter

Diagonal Diverters (full diverter, diagonal road closure)

Canadian Design Diagonal Diverter

Median Barriers (median diverter, forced turn island, island diverter)

Forced Turn Islands (forced turn channelizations, pork chops, right turn islands)

Permeable Half Closures and Diverters

Concern About Compliance

Strong Cut-Through Pressure and Poor Design

Designing Half Closures for Compliance

Speed Humps (undulations)

12' Speed Hump Profile

ITE Speed Hump Guidelines

14' Speed Hump Profile

Other Hump Profiles

Four Different Rises

Aesthetics of Speed Humps

Prefabricated Speed Hump (Portland, OR)

Speed Tables (trapezoidal humps, flat topped humps)

22' Speed Table Profile Seminole County, FL

Alternate 22' Speed Table Profile Gwinnett County, GA

Gentler Ride for All Vehicles

Serving As Raised Crosswalks

Other Speed Table Profiles

Canadian Design Raised Crosswalk

Raised Intersections (raised junctions, intersection humps, plateaus)

Urban Design Element

Canadian Design Raised Intersection

Traffic Circles (rotaries, intersection islands)

Designing Circles to Fit Intersections

Circle Diameter vs. Street Width and Corner Radius (Seattle)

Accommodating Large Vehicles

Traffic Circles -- A Hazard to Bicyclists?

Traffic Circles as Civic Expressions

Deflection at T-Intersections

Modern Roundabouts

Roundabouts vs. Mini-Traffic Circles

Roundabouts vs. Old-Fashioned Traffic Circles

Chicanes (deviations, serpentines, reversing curves)

Cutting Corners at Chicanes

Designing Chicanes for Compliance

Canadian DesignChicane

Other Horizontal Measures

Horizontal Deflection via On-Street Parking

Neckdowns (nubs, bulbouts, knuckles, intersection narrowings, corner bulges)

Pedestrianizing Intersections

Chokers (pinch points, midblock narrowings, curb extensions, midblock yield points)

Safe Cross Designs

One-Lane Chokers

One and One-Half Lane Choker

Center Island Narrowings (midblock medians, pedestrian refuge, median slowpoints, median chokers)

Gateway Treatments

A Break for Pedestrians

Where Center Islands Are Most Effective

Narrowings -- A Hazard to Bicyclists?

Preferred Treatments for Bicyclists

Combined Measures

Standard Cost Estimates