Attachment

ATTACHMENT #1 SA&T Committee Meeting of 10/28/2009 Traffic Calming Treatments February 10, 2009 SA&T Committee Meeting of 10/28/2009 ATTACHMENT #1

Objectives of Traffic Calming Traffic calming may be used to address safety issues on neighborhood streets: • Discourage speeding • Raise awareness of conflicting traffic movements • Enhance pedestrian safety • Discourage use of neighborhood streets as high-speed bypasses around congestion on major highways.

Typical Treatments Intersection Treatments • Roundabouts • Realigned Intersections Midblock treatments • Median treatments • Bulbouts • Chicanes

Roundabouts • Traffic entering the circle yields to traffic already in the circle. • Deflection forces reduced speeds through the intersection. • Splitter islands for larger roundabouts can serve as pedestrian refuge. • Center island can be designed to accommodate larger vehicles. • “Mini-roundabouts” can often provide traffic-calming benefits without requiring widening.

Realigned Intersections • Converts “T” intersection to all-way stop. • Bulbout island discourages through- street traffic from “blowing through” the intersection. • Enhances visibility of side street traffic from through-street approaches. • Creates an opportunity for all-way stops at intersections that would not ordinarily meet warrants.

Median treatments • Median separation, either midblock or at intersection approaches. • Appropriate for wider roadways; islands channel traffic and narrow the roadway, encouraging slower speeds. • Pedestrian safety is enhanced by limiting crossings to one traffic direction at a time. Islands may serve as refuge areas. • May be combined with bumpouts to create chicanes.

Chicanes • Chicanes create deflection in the travel lanes through a combination of bumpouts and median islands. • Designed to force travel speeds more consistent with speed limits. • Islands and bumpouts can shorten crossing distance or provide median refuges, enhancing safety at midblock ped crossings.