css classes 19 22 - developing compatible supportive design 120309

Context Sensitive Solutions in Transportation Planning, Environmental

Analysis and Design

1

Classes 19-22

Using CSS to Develop Compatible Supportive

Designs


Analysis and Design

Excellent transportation design• Satisfies stakeholder purpose, needs, and

vision– Established early– Refined as process advances

• Safe for users and community• Harmonious with community• Supports other community objectives• Preserves environmental values and resources

Goal: Excellence

2


Analysis and Design

Project development process• Determine context

– Existing conditions• Physical

– Roadway, transitway, pathway– Roadside, streetside, wayside– Adjacent development

» Context zones » Land use site design» External factors

• Activity– Transportation facility– Roadside, streetside, wayside– Adjacent land, buildings

Process (Review)

3


Analysis and Design

Project development process (cont.)• Determine context (cont.)

– Environment (relevant)• Physical• Social

– Planed changes– External factors

Process (Review)

4

CS3 – context sensitive sustainable solutions (Oregon DOT version)


Analysis and Design

Project development process (cont.)• Identify issues, opportunities, constraints,

threats, strengths, weaknesses– Issues – concerns, problems, questions,

uncertainties– Opportunities – what could occur (physical,

operational, policy, transportation, development, economic, etc.)

– Constraints – limitations on opportunities– Threats – negative factors or prospects– Strengths – positive attributes on which to build– Weaknesses – shortcomings to strengthen

Process (Review)

5


Analysis and Design

Project development process (cont.)• Identfy goals, objectives, core values

– Desired outcomes• Goals (general statements)

– Mobility and access– Economic development– Land development– Activity– Other

• Objectives– More detailed statements

Process (Review)

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– Core values• Aesthetics• Safety• Character • Etc.


Analysis and Design

Project development process (cont.)• Select criteria for evaluation, prioritization

– Base on• Objectives• Issues• Opportunities • Concerns• Environmental impacts

Process (Review)

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• Mobility• Socio-econimic• Environmental• Cost-

effectiveness• Other


Analysis and Design

Project development process (cont.)

• Vision

– Outcome from goals

• Functional

• Appearance

• Resulting conditions

Process (Review)

8


Analysis and DesignProject Development

9

Develop alternatives

• Range

• Design criteria

• Approach

• Flexibility

• Components

Conventional

CSS



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Develop alternatives• Range in magnitude

– “No build”• May include improvements elsewhere in

system – Operational (TSM) improvements – Minor– Full “build”

• Range in type– Modal– Alignment– Type of facility– Extent of improvement– Relationship with adjacent

development



11

Develop alternatives• Design criteria

– AASHTO green book (using flexibility)– AASHTO, FHWA Flexibility in Highway

Design– State DOT design manual– City/county public works design manual– Local agency guidelines (incl. zoning

overlays)– Modal guidelines (ITE CSS for walkable

communities)• Ped – AASHTO ped guide• Bike – AASHTO bike facilities guide• Bus – TCRP 19, 33, 117• Rail – TCRP 17, 69

– Landscaping

(pendingTCRP D-09 guide)



12

Develop alternatives



13

Develop alternatives• Components

– Traveled way– Streetside, roadside, wayside– Land uses– Sense of place

• Urban design• Parks• Historic features• Social fabric• Arts and activity

– Design each– Adapt per activity– Enhance each to

work together


Analysis and Design

BUILT ENVIRONMENT

WHAT DECISIONS

?

Land UseTOD Circulation

WHO DECIDES?

City CouncilsBoard of Supervisors

COMMUNITY

INFLUENCEDirect engagement

Decision-Making Context

TRANSIT SERVICE

S

ServicesVehicles

Connectivity

Transit Agency Boards

Customers

Incorporate community input into decisions

THEPROJECT

AlignmentVehicles

OperationsStationsServices

JPB/CHSRA Boards

Federal agenciesElected officials

PRP

Customers

Facilitate community

engagement

Regional/state accountabilility

HSR

AlignmentVehicles

OperationsStationsServices

CHSRA BoardFederal

agenciesElected officials

Customers

consider community

input in decisions

Statewide accountability

Caltrain improvements – S.F. peninsula line



15

Evaluate• One measure per objective or issue

– Quantifiable (with available data)

– Sensitive to changes in performance

• Can be categorical or ratio

• Need quantification methodology

• Can work within Delphi process



16

Evaluate – Option: Delphi process• Combines performance and importance• One measure per criterion

– Objective– Issue

• Quantified in ratio scale• Criteria weighted per stakeholder input

– Initial– Again after interim results


Analysis and Design

• Delphi example(or other evaluation table)

Project Development

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Evaluation• Converge by narrowing, refining alternatives

1. Distinct ranging alternatives

2. Workable more detailed alternatives

3. (optional) Variations on final alternative(s)

4. Preferred alternative

5. Develop preliminary design

Cycle1.Formulate/ refine

2.Evaluate 3.Discuss4.NarrowEIS


Analysis and Design

Communities want• Flexibility• Compatibility with adjacent land uses• Balanced land use/transportation

functions• Safe and attractive streets• Multimodal facilities• Streets that are quality public space

Developing Designs

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Analysis and Design*Transportation design for livable communities

Examples of flexible DOT design criteria

Minimum lane widths

FDOT TDLC Roads*

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Analysis and Design

Techniques to support non-drive modes

FDOT TDLC roads

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Analysis and Design

Tenets of CSS• Balance

– Safety– Mobility– Community objectives– Environment

• Multimodal• Involve public,

stakeholders• Interdisciplinary teams• Flexibility in design• Incorporate aesthetics

Developing Designs

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Analysis and Design

Placemaking• Community-based approach to the development and

revitalization of cities and neighborhoods• Placemaking:

– Unique places with lasting value – Compact, mixed-use – Pedestrian and transit oriented– Strong civic character– Contributes to economic development

Developing Designs

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Analysis and Design

ITE framework• Context zones:

– Suburbs to downtowns• Street classification:

– Functional class – Thoroughfare type

• Boulevard• Avenue• Street

• Compatibility

Developing Designs

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Analysis and Design

Source: Context Sensitive Solutions in Designing Major Urban Thoroughfares for Walkable Communities

Context Zones – An Organizing System for Thoroughfare Design

Source: Duany Plater-Zyberk and CompanyGraphic source: Duany Plater-Zyberk and Company

Developing Designs


Analysis and Design

Features that create context• Land use

– Defines urban activity– Major factor in design criteria

• Site design – Arrangement of buildings, circulation, parking and landscape– Vehicle or pedestrian-orientation

• Building design– Height, massing shape context– Create enclosure/pedestrian interest

Developing Designs

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Analysis and Design

Land use influence• Major factor in thoroughfare design• Influences:

• Travel demand• Activity in roadside• Width of roadside• On-street parking• Target speed• Freight and transit

Developing Designs

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Analysis and Design

Site design

Developing Designs

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Feature Auto Oriented Pedestrian Oriented

Building Orientation and Setback

– Set well back into private property

– Oriented to parking or landscape

– Oriented to, and adjacent to street

– Direct pedestrian entrance on street

– Integrated with street using stoops, arcades, cafes

Parking Type and Orientation

– Surface lot between buildings and street

– Under or behind building access by alleys

– Structured– On-street

Block Length - Large blocks, often with no public throughway

- Superblocks

- Short blocks- High connected network


Analysis and Design

Building design• Significant contributor to

context defined by:– Height and thoroughfare

enclosure– Width– Scale and variety– Entries

Developing Designs

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Analysis and Design

Street enclosure• Building height to

thoroughfare width ratios:– 1:4 suburban– 1:2-1:3 urban

• Pedestrians first perceive enclosure at a 1:4 ratio

Developing Designs

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Analysis and Design

CSS tenet - thoroughfare design changes as context changesThe thoroughfare both responds to and contributes to shaping the context and defining the place

Developing Designs

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Analysis and Design

Thoroughfare types• Three classifications:

– Boulevard– Avenue– Street

• Basis for:– Physical configuration– Design criteria– Design speed

Developing Designs

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Analysis and Design

Functional classification in thoroughfare design

• Function and role in the network – Continuity– Trip purpose and length – Level of land access– Type of freight– Types of public transit

• Design controls – Design speed for sight distance– Horizontal and vertical curvature

Developing Designs

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Analysis and Design

Relationship: functional classification and thoroughfare type

Developing Designs

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Analysis and Design

Thoroughfare type in design• Design criteria

– Target speed (desirable operating speed)• Physical configuration

– With surrounding context• Dimensions for:

– Roadside– Traveled way– Intersections

Developing Designs

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Analysis and Design

Thoroughfare type characteristics

Developing Designs

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Analysis and Design

Speed reduction techniques

FDOT TDLC Roads

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Analysis and Design

Boulevard• Divided arterial (4+ lanes)• Target speed (35 mph or

less) • Through and local traffic• Serve longer trips • Access management• Major transit corridor• Primary freight route• Emergency response route • Limited curb parking

Developing Designs

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Analysis and Design

Boulevard

Developing Designs

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Analysis and Design

Multi-way boulevard• Characterized by:

– Central roadway for through traffic – Parallel roadways access abutting property,

parking, and pedestrian and bicycle facilities

– Parallel roadways separated from the through lanes by curbed islands

• Require significant right-of-way• Special treatment of intersections

Developing Designs

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Analysis and Design

Multi-way boulevard

Developing Designs

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Analysis and Design

Avenue• Arterial or collector (4 lanes max)• Target speed (30 to 35 mph) • Land access• Primary ped and bike route • Local transit route• Freight - local deliveries• Optional raised landscaped median• Curb parking

Developing Designs

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Analysis and Design

Street• Collector or local street (2

lanes)• Target speed (25 mph) • Land access primary function• Designed to:

– Connect residential neighborhoods

– Connect neighborhoods with commercial districts

– Connect local streets to arterials • May be commercial main

street • Emphasizes curb parking• Freight restricted to local

deliveries

Developing Designs

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Analysis and Design

Changing Thoroughfare & Context• Arterial Street• C-3: Suburban

Existing ConditionsSource: TJPDC, VDOT, City of Charlottesville, & Albemarle Co.

CD+A, Meyer, Mohaddes, & Urban Advantage

Developing Designs


Analysis and Design

• Boulevard Thoroughfare• C-4: General Urban

Alternative Future with Initial NetworkSource: TJPDC, VDOT, City of Charlottesville, & Albemarle Co.


Changing Thoroughfare & Context

Developing Designs


Analysis and Design

• Avenue Thoroughfare• C-5: Urban Center

Alternative Future with Potential “Full” NetworkSource: TJPDC, VDOT, City of Charlottesville, & Albemarle Co.


Changing Thoroughfare & Context

Developing Designs


Analysis and Design

Design controls• Speed• Design vehicle• Functional class• Location• Sight distance• Horizontal / vertical alignment• Access management• Pedestrians and bicyclists

Developing Designs

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Analysis and Design

Speed definitions• Target speed

– Desirable operating speed in specific context

– Balances • Vehicle mobility • Safe environment

– Usually posted speed limit– In CSS set by context and thoroughfare type

• Design speed– Governs certain geometric features– Usually set by functional classification

Developing Designs

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Analysis and DesignDeveloping Designs

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• Design Vehicle– Accommodated

without encroachment

– Turns with considerable frequency

– High volumes in opposing lanes

– Example: bus

• Control Vehicle– Encroachment

allowed– Turns infrequently– Example:

emergency vehicle

Design vs. Control Vehicle


Analysis and Design

Emergency vehicle operations• Turning capability• Access (clear areas)

– Building entrances– Hydrants– Walls

• Mountable median crossings (long blocks)

• Work with fire department

Developing Designs

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Analysis and Design

CSS vs. conventional design

Developing Designs

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Conventional CSS Approach

Context: UrbanRural

Urban Context:SuburbanGeneral UrbanUrban CenterUrban Core

Design criteria based primarily on:

Functional classDesign speedTravel demand forecastsLevel of service objectives

Design criteria based primarily on:

Community objectivesThoroughfare typeFunctional classAdjacent land use


Analysis and Design

Speed and capacity of urban streets• Address capacity issues with:

– Network capacity– Synchronized signal timing– Access management– Turn lanes– Other operational refinements

• Address safety: – Case-by-case basis

Developing Designs

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Analysis and Design

CSS design process

Developing Designs

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Thoroughfare Components

Roadside


Analysis and Design

Considerations in cross-section design

Developing Designs

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• Local objectives• Stakeholder

priorities• Adjacent activities• Functional class• Context zone and

thoroughfare type• Modal requirements• Other conditions

– Right-of-way– Traffic volumes– Vehicle mix


Analysis and Design

Stages in cross-section design1. Establish general parameters based on:

– Context zone– Thoroughfare type– Select starting cross-section

2. Determine number of lanes based on:– Community objectives– Thoroughfare type– Long-range transportation plan– Corridor/network capacity analysis– Maximum 6 lanes in walkable urban areas

Developing Designs

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Analysis and Design

Stages in cross-section design3. Determine design and control vehicle4. Identify transit, freight, and bicycle

requirements– Establish dimensions

5. Develop ideal cross-section - compare to ROW

– Acquire ROW or narrow design elements, or– Widen high priority elements to match ROW– Avoid combining minimal widths

Developing Designs

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Analysis and Design

Designing in constrained ROW• Prioritize design elements• Develop sections

– Optimal – unconstrained– Predominant – all priority elements– Functional minimum – many priority

elements– Absolute minimum – highest priority only

• ROW width less than absolute minimum– Acquire ROW incrementally– Change thoroughfare type

Developing Designs

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Analysis and Design

Lane widths• Up to 35 mph: 10-12 feet• Over 35 mph: 11-12 feet• With buses: 11-12 feet• Bike lanes: 5-6 feet (4 feet outside

gutter pan)• Parking: 7-8 feet

Developing Designs

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Analysis and Design

Medians• Functions

– Access management– Pedestrian refuge– Left turn lanes– Aesthetics

• Widths– 4-22 feet

• Landscaping– Trees (45 mph or less)

• 6-10 foot medians - less than 4 inch caliper

• 1½ feet lateral clearance

Developing Designs

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Analysis and Design

Transitions• Geometric transitions (use AASHTO)

– Change in thoroughfare width– Lateral shifts– Lane drops

• Location: on tangent sections• Context, visual, operational, environmental

transition– Speed zone transition– Visual cues

• Urban design, land uses, building design, gateways, signs– Change width of thoroughfare

Developing Designs

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Analysis and Design

Excerpt from ITE CSS guide – cross-sections

Developing Designs

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Analysis and Design

Streetside design• From property line to face of curb• Accommodates street activity

– Mobility– Business– Social

• Public space

Developing Designs

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Analysis and Design

Urban streetside uses• Movement of pedestrians• Access to buildings/property• Utilities/appurtenances• Transit stops• Landscaping• Urban design/public art• Sidewalk cafes• Business functions• Civic spaces (plazas, seating)

Developing Designs

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Analysis and Design

Streetside components• Streetside zones:

– Edge Zone– Furnishings Zone– Throughway Zone (ADA)– Frontage Zone

• Function and dimensions vary by context zone and adjacent land use

Developing Designs

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Analysis and Design

Streetside cross-section guidelines

Developing Designs

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1.5 feet2.5 feet at diagonal parking


0.5 feet

7 feet(trees in tree wells)


8 feet(landscape strip w/ trees and grasses or

groundcovers)

10 feet 8 feet 8 feet

3 feet 2.5 feet0 feet along lawn and groundcover

1 foot along low walls, fences, and hedges1.5 feet along facades, tall walls, and fences

0.5 feet

10 feet(landscape strip w/ trees and groundcovers or

low shrubs)

8 feet

0 feet along lawn and groundcover1 foot along low walls, fences, and hedges

1.5 feet along facades, tall walls, and fences



0.5 feet

WithParking

6 feettrees in tree wells



groundcovers)

WithoutParking

8 feet with buffer landscaping




3 feet 2.5 feet0 feet along lawn and groundcover




0.5 feet




groundcovers)


2.5 feet 2.5 feet0 feet along lawn and groundcover


C-4 w/ Predominantly Residential Frontage

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C-6 and C-5C-4 w/ Predominantly Commercial Ground

Floor Use

Throughway

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THIS THOROUGHFARE TYPE NOT APPLICABLE TO THE PREDOMINANTLY COMMERCIAL GROUND FLOOR LAND USES FOUND IN C-4 THROUGH C-6 CONTEXT

ZONES


Analysis and Design

Edge zone• Interface with traveled way

• Functions– Vehicle overhang and clearance

– Door opening area

– Wheelchair access at transit stops

• No (rural) clear zone width

• Lateral clearance– 1½ ft from curb face

Developing Designs

67


Analysis and Design

Furnishings zone• Buffers pedestrians from

traveled way• Functions

– Street furniture, public art– Utilities (within zone)– Transit stops– Lighting– Public spaces (seating)– Business space (cafes)– Landscaping

• Safe landscaping– Sight lines (CPTED)– Sight distances

Developing Designs

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Analysis and Design

Throughway and frontage zones• Throughway zone

– Clear area for pedestrian travel– ADAAG requirements– No utilities

• Frontage zone– Area adjacent to property line– “Shy” distance from buildings– Business space (cafes, signs)– Landscaping– Seating– Building access

Developing Designs

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Analysis and Design

Clear zones on urban thoroughfares• Defined as an edge zone clear of fixed

objects• Less consequence than rural context

– Lower speeds– Parked vehicles

• Often not practical in urban areas• Rural standards not used in urban

walkable areas

Developing Designs

70


Analysis and Design

Driveways• Minimize in high pedestrian activity areas• Maintain sidewalk cross slope

Developing Designs

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Best If necessary


Analysis and Design

Traveled way• Central portion of thoroughfare between

curbs• Provides for movement of vehicles• Interface with roadside via on-street

parking

Developing Designs

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Analysis and Design

Traveled way components• Functions, modes• Widths, ROW allocations• Through travel and turn lanes• Access management• Parking, transit stops, bike lanes• Emergency vehicle operations• Transitions• Mid-block crosswalks• Medians, pedestrian refuge

islands

Developing Designs

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Analysis and Design

Lane widths• Recommended practice

– Urban freeways: • 12 feet normal• 11 feet constrained

– Arterials and collectors• 10–11 feet on arterials and

collectors• 12-feet under special circumstances

– Based on:• Target speed• Design vehicle• Right-of-way• Width of adjacent parking and

bicycle lanes

Developing Designs

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Analysis and Design

Medians• Recommended practice

Developing Designs

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Recommended Median Widths on Low Speed Thoroughfares (35 mph or less)

Thoroughfare TypeMinimum

WidthRecommende

d Width

Median for access control

Arterial Boulevards and Avenues4 ft. 6 ft.

Collector Avenues and Streets

Median for pedestrian refuge



Median for street trees and lighting



Median for single left-turn lane

Collector Avenues and Streets 10 ft. 14 ft.

Arterial Boulevards and Avenues 12 ft. 16-18 ft.

Median for dual left turn lane

Arterial Boulevards and Avenues 20 ft. 22 ft.


Analysis and Design

Street trees - Recommended practice• In medians

– Min. median width• 6 feet for up to 4” caliper trees• 10 feet for larger trees

– Avoid trees larger than 4” caliper • Speed > 45 mph• Or use barrier

Developing Designs

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Analysis and Design

Bicycle lanes• Recommended practice

– Combined with on-street parking = 13 feet– Without on-street parking = 6 feet

Developing Designs

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Analysis and Design

On-street parking – recommended practice

Developing Designs

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Recommended Parallel Parking Lane Widths

Thoroughfare Type in C-3 through C-6 Context Zones

Parallel Parking Lane Width (commercial and residential areas)

Arterial Boulevard (commercial) 8 ft.

Arterial Boulevard (residential) 7 ft.

Parallel Parking Lane Width (residential areas)

Arterial Avenue 7 ft.

Collector Avenue and Street 7 ft.

Parallel Parking Lane Width (commercial areas)

Arterial Avenue 8 ft.

Collector Avenue and Street 8 ft.


Analysis and Design

• Mid-block crosswalks - Recommended practice– Locate so crossings are 200-300 feet apart– Significant pedestrian demand– Criteria

• 12,000 ADT or less• 15,000 ADT with median refuge• Speed less than 40 mph• Adequate sight distance

Developing Designs

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Analysis and Design

Urban intersections• General principles

– Minimize conflicts between modes

– Minimize pedestrian exposure– Provide crosswalks on all

approaches– Minimize curb radii consistent

with design/control vehicle– Ensure good visibility– Balance vehicle LOS with

pedestrian convenience and safety

Developing Designs

80


Analysis and Design

• Urban intersections - Design elements– Through and turning lanes– Intersection sight distance– Medians– Curb return radii– Design vehicle– Channelized right turns– Modern roundabouts– Crosswalks and refuges– Curb extensions– Bicycle lane treatment– Bus stops– Traffic signals

Developing Designs

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Analysis and Design

Urban intersections• Avoid large undefined open spaces

Developing Designs

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Source: City of Palo AltoCD+A, FPA, and Urban Advantage


Analysis and Design

Urban intersections - Creating opportunities to improve context

Developing Designs

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Source: City of Palo AltoCD+A, FPA, and Urban Advantage


Analysis and Design

Intersections – simplify for all modes

Developing Designs

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Analysis and Design

• Intersections – Curb return radius - recommended practice– Consider

• Design vehicle• Effective width• Curb return radii

– Minimum radius = 5 feet– Use 10-15 feet radius

• High ped volumes• Low turning volumes and speed• Bike/parking lanes create higher effective radii

Developing Designs

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Analysis and Design

Curb extension and effective corner radius

FDOT TDLC Roads

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Analysis and Design

Curb extensions• Improve visibility

• Reduce crossing width

• On streets with parking

• Recommended practice– Extend curb line 1 ft. less than

parking width

– Curb return radius for control vehicle

– Use with bus stops to increase waiting area

Developing Designs

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Analysis and Design

Channelized right turns - recommended practice

• Generally discouraged in walkable environments

• Signalized intersections with heavy right turns

• Low pedestrian volumes• Where pedestrian volumes high –

eliminate or install pedestrian signal• Low-angle turn• Clear visibility• Illumination

Developing Designs

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Analysis and Design

Roundabouts - recommended practice

Developing Designs

89

Parameter

Minimum “Mini-

Roundabout”

Urban Compact

Roundabout

Urban Single-Lane Roundabout

Urban Double-Lane Roundabout

Maximum Entry Speed (mph) 15 15 20 25

Design Vehicle

Bus and Single-unit truck drive over apron

Bus and Single-Unit

Truck WB-50

WB-67 with lane

encroachment on truck apron

Inscribed circle diameter (feet) 45 to 80 80 to 100 100 to 130 150 to 180 Maximum number of entering lanes

1 1 1 2

Typical capacity (vehicles per day entering from all approaches)

10,000 15,000 20,000 40,000

Applicability by Thoroughfare Type:

Boulevard Not

Applicable Not

Applicable Not

Applicable Applicable

Arterial Avenue Not

Applicable Not

Applicable Applicable Applicable

Collector Avenue Applicable Not

Applicable Applicable Not Applicable

Street Applicable Applicable Applicable Not Applicable



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Analysis and Design

Roundabouts

Developing Designs

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Analysis and Design

Design exceptions – 13 controlling criteria– Design/target speed– Lane width– Shoulder width– Bridge width– Horizontal alignment– Superelevation– Cross slope

• Needed when– Cannot meet minimums in applicable design

manual– Reasonable alternative design will work safely

Design Exceptions

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• Vertical alignment• Grade• Stopping sight distance• Vertical clearance• Horizontal clearance• Structural capacity


Analysis and Design

Number state DOTs reporting frequent design exceptions by criterionNCHRP Synthesis 316

Frequent design Exceptions

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Analysis and Design

Consider trade-offs• Mobility, access• Road user needs• Environmental impacts• Capital and operating

costs• Safety• Aesthetics• Local considerations

Design Exceptions

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Analysis and DesignDesign Exceptions

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Spe

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Design Domain and Risk

Adapted from: O. Arndt, R. Cox, “Using an Enlarged Design Domain for Road Restoration Projects,” Queensland Department of Main Roads, 2006.

Design Criteria

Decreasing scope for defense

Extended

Design Domain

Normal

Standard Minimums

Lower limit of extended design domain – existing roads

Increasing liability risk,

Lower limit of extended design domain – new roads


Analysis and Design

• Strong case– Show criteria not applicable

• Project can be safe not following criteria• Environmental or community needs prohibit

meeting criteria• Criteria impractical to meet

– Weak case• Saves money• Saves time• Designer found loop hole• Design similar to other existing designs

Design Exceptions

96


Analysis and Design

Minimum documentation• Established design criteria• Reasons criteria cannot be met• Why proposal is most applicable• Applicable background information• Pertinent information

– Safety assessment– Operations

Design Exceptions

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Analysis and DesignDesign Exception Form

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Analysis and Design

Documentation must be• Deliberative• Defensible• Clearly written• Explicitly evaluate safety

– Who is at risk• Motorists, pedestrians, etc.

– Exposure• Traffic volumes• Location

– Extent of exception– How risk is managed (solely relying on standards

does not guaranty facility free of risk)

Design Exceptions

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Analysis and DesignDesign Exception Process

100

Florida DOT design and utility exception process


Analysis and Design

Rule of thumb for success• No reasonable, feasible, practical solution

available that meets criteria, or• Selection of proposed criteria is advantageous

and results in overall superior designand• Use of proposed criteria is not expected to

unduly degrade or hinder safety or operational performance of the proposed facility

Design Exceptions

101


Analysis and Design

Reference (available on-line):

Design Exceptions

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Analysis and DesignAASHTO• A Guide for Achieving Flexibility in Highway Design, 1st Edition• A Policy on Geometric Design of Highways and Streets, 5th Edition• Guide for the Planning, Design, and Operation of Pedestrian Facilities, 1st Edition• Guide for High-Occupancy Vehicle (HOV) Facilities, 3rd Edition• Guide for Park-and-Ride Facilities, 2nd Edition• Guide for the Development of Bicycle Facilities, 3rd Edition• Roadside Design Guide, 3rd Edition• Roadway Lighting Design Guide• Design for Transit Vehicles and Facilities on Streets and Highways (pending from TCRP D-09)

ITE• Context Sensitive Solutions in Designing Major Urban Thoroughfares for Walkable Communities (2nd edition pending – retitled to Designing Walkable Urban Thoroughfares: A Context Sensitive Approach)

• Urban Geometric Design Handbook• Guidelines for Driveway Location and Design• Guidelines for Neighborhood Street DesignTRB• A Guide for Transportation Landscape and Environmental Design (update pending)• Access Management Manual

Design References

103


Analysis and Design

Class Project Discussion

104

• Projects to be – Presented Class 28– Submitted at start of Class 29

• Student questions?

css classes 19 22 - developing compatible supportive design 120309

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