Designing Complete Streets: What you need to know
Getting from this
to this. Continuous sidewalk Buffer w/trees Bicycle lane Raised median Buildings close to the street
Flexibility in design
Design and context
Design Speed and Design Vehicle 20 30 40 50 60 70 10 80 0 90
The need for Conventional design theory: Speed = Capacity
Speed vs. design scale Speed Scale/design geometrics
Wide lanes
Setbacks
Big intersections
Designing for speed
Designing for speed?
Design speed does not determine capacity in urban areas intersection operations/delay is major determinant.
Design Scale in Walkable Streets
Speed vs. design scale Speed Complete Streets Scale/design geometrics
Speed vs. Pedestrian safety Source: New Jersey DOT
Recommended practice for Complete Streets Maximum posted (target) speed 35 mph Maximum design speed 40 mph
Selecting the appropriate design vehicle Don t design for the exception
Road Diets
Many overly wide roads could use a road diet
What s a road diet? Classic road diet shrinks 4 lanes to 3 + bike lanes
Another road diet example Classic road diet shrinks 4 lanes to 3 + bike lanes
What else does a road diet do? Creates room for wider sidewalks
What else does a road diet do? Encourage appropriate operating speeds (consistent with design speed) Reclaims ROW for other features Bicycle lanes Wider sidewalks Street trees On-street parking Wider medians/turn lane Etc. An inexpensive tool for retrofitting existing streets
Four lane to three-lane conversion 4 2 12 12 12 12 2 4 6 2 12 12 12 12 2 6 10 2 4 11 10 11 4 2 10 6 2 8 11 10 11 8 2 6
Four to three lane reductions can actually enhance safety and capacity
Four lanes versus three X vs.
Four lanes versus three X vs.
Road Diet on Washington Street
Road Diet on Washington Street
Case study research Source; Converting four lane undivided roadways to a three-lane cross-section: Factors to consider. Iowa State University and Iowa DOT
Guidelines for Complete Streets: Lane reductions
Sidewalks and paths
Design elements Sidewalks Frontage zone Pedestrian zone Eight feet min. Furniture Zone (clear zone)
Minimum width is unacceptable
With higher vehicle speeds & volumes wider is better
On-street parking
On-street parking: Relationship to livable communities Intended for low-speed environments Provides buffer between roadside/pedestrians and traveled way
Back-in angle parking Improves visibility Improves safety for bicyclist Source: Walkable Communities, Inc.
Bulb-outs & curb extensions Provide visibility at intersections and mid-block crossing
Bicycle lanes
On-street bicycle facilities Shared facility Wide outside lane Designated bicycle lane Paved shoulder
Lane width reductions Existing 2 12 12 2 12 2 12 12 2 Proposed 2 4 11 11 12 11 11 4 2 Stripe 4 bicycle lane Reduce travel lane width to 11 Eliminate offset (design speed =< 35 mph)
Will bike lanes create safety issues?
Bike lanes can make streets safer, by. Creating appropriate lane widths Encouraging appropriate operating speeds Creating a soft buffer between travel lanes and roadside objects
Transit facilities
Transit facilities: relationship to complete streets Safe, deliberate facility for transit access Establishes legitimacy of transit Improved bus/vehicular operations and safety
Integrate transit with street design
Medians
Medians: Relationship to Complete Streets Safety Reduced vehicular crashes Crossing refuge for pedestrians Roadway character Can encourage more appropriate operating speeds Terminates long vistas Opportunities for landscaping enhancement
Medians improve safety at driveways
Medians and Islands Reduce crashes by 40%
Medians reduce crash risk for random midblock crossings
Flush median is not much of a refuge
Flush median is not much of a refuge
Basic Principle Break long complex crossing into two simpler crossings
Street trees and fixed objects
Relationship to Complete Streets Important buffer between pedestrian and travel lanes Contributes to roadway character Contributes to driver perception of speed
Plans Preparation Manual Ch. 2 Horizontal clearance Distance between the face of the curb and a roadside feature Horizontal clearance
Vehicular separation is critical to a walkable environment Pedestrians feel exposed and vulnerable within a constrained ROW, flexibility in clearance is absolutely essential!
Intersections
Intersection are barriers No/poor treatments Long crossing distance peds feel exposed Higher speed vehicular turn movements
Large radii 1. Increase crossing distance and 2. Make crosswalk & ramp placement more difficult
Effect of large radius on drivers They drive fast, ignoring pedestrians Tigard OR
Green Streets A green street can be defined as a street designed to: integrate a system of stormwater management within its right of way reduce the amount of water that is piped directly to streams and rivers be a visible component of a system of green infrastructure that is incorporated into the aesthetics of the community make the best use of the street tree canopy for stormwater interception as well as temperature mitigation and air quality improvement ensure the street has the least impact on its surroundings, particularly at locations where it crosses a stream or other sensitive area. The design and construction of green streets is one component of a larger watershed approach to improving the region's water quality, and requires a more broad-based alliance for its planning, funding, maintenance and monitoring. 2007 Alabama ASCE Summer Conference 76
Complete Streets are A way of addressing the needs of all potential users Based on sound engineering judgment and principals Unique to each specific street Safe, efficient and economically viable for all users