“Pavement Audit” for Greenville and Pickens Counties

Diagnosis Report to Focus Group

January 25, 2006

Presentation Overview

• Lawrence Group • Scope of Audit• Audit Methodology• Recommendations/

Findings• Questions/Feedback/Next

Steps

The Lawrence Group

• Founded in St. Louis in 1983

• Carolinas office in Davidson, NC

• Town Planning & Architecture

• Municipal, non-profit, and developer clients

Lawrence Group Projects

Mooresville, NC Code

Haynie-Sirrine Master Plan – Greenville, SC

General Development Guidelines – Research Triangle,

NC

Active Living Assessment

Concord-Roberta Church Small Area Plan - Concord,

NC

Woodlands-Davidson, NC

Belmont Reserve-Belmont, NC

Project Scope

Saluda-Reedy Watershed

“. . .non-point source pollution – sediment, nutrients and waste carried by storm water – is now the chief threat to these rivers. . .

It will take a concerted effort by

community leaders across the Upstate to effectively address the threats of non-point source pollution fed by rapid development . . .”

-SRWC

Project Scope

•“. . . audit of paving requirements in the codes and ordinances of Greenville and Pickens Counties. . .”

•“Identify opportunities. . .to reduce the amount of impervious cover generated by new development.”

Project Scope

Ordinances Reviewed

Greenville County

– City of Greenville

– Greenville LUDO– Fountain Inn

– Greer – Mauldin

– Simpsonville– Travelers Rest

Pickens County– Central

– Clemson– Easley– Liberty

– (Pickens)

Methodology

• Zoning Ordinances and Land Development Regulations

• Based on “Builders for the Bay” process (www.cwp.org)

• 10 major categories; 36 factors

Methodology

• Major Categories– Street width– Right-of-way width– Cul-de-sac design– Street drainage (swales v. curb

& gutter)– Parking ratios– Shared parking– Parking lot design– Parking lot landscaping– Sidewalks and planting strips– Driveways

Imperviousness

Rooftops + Car space

Transport-related impervious cover: 60-

70%(streets + parking

areas)

Roof tops: 30-40%

Imperviousness

Street Design

• Local Streets: 20-24 feet• Could be as narrow as 16-

18 ft

Street Width

• Minimum street widths

Street Width

Street Width

• Local Streets: 20-24 feet• Cul-de-Sac streets: 22-28

ft– Could be as narrow as 18 ft

• Manufactured home park streets: 20-28 ft– Should be same as local streets

• Alleys: 12-30 feet (Greenville County standard is

good: 12-18 ft)

Street Width

• Local Streets: 20-24 ft• Cul-de-Sac streets: 22-28

ft• Manufactured home park

streets: 20-28 ft• Alleys: 12-30 ft

(Greenville County standard is perfect)

• Collector Streets: 24-40 ft– Could be as narrow as 20 ft– Consider parking, bike lanes,

turn lanes

Curb Radii

• 25-40 ft (Greenville County)

• Pickens Co: Not specified• AASHTO Guidelines:

– Local/local: 10-15 ft

– Local/collector: 15-20 ft

– Collector/collector: 15-25 ft

Right-of-Way Width

• 40-50 ft; typically 50 ft

• Could be as narrow as 34-38 ft.

• Allow utilities in the street

Cul-de-sac Design

• Typical: 40 ft(Greenville: 41 ft; Clemson: 35

ft)

• Landscaped Islands: 8 of 13 allow

• Alternate turn-arounds: – Greenville: yes– Pickens: no

Cul-de-sac Design

• Cul-de-sac islands: – Greenville Co.: typically yes– Pickens Co: typically no

Open Channels/Swales

• Only Clemson, Easely, Liberty require curb & gutter on all streets

• Pickens County swales: < 2 dua; slopes “not excessive”

• Tom Schueler:– No slopes > 5%– Runoff velocities > 4-5 ft/sec.– Soils/climate don’t allow dense

turf– Water table < 1 ft below channel– No densities > 3 dua

Sidewalks

• Context-sensitive requirements– Based on street-type (Clemson)– Development density (> 2 dua)– Proximity to schools (1-1.5 miles)

• One side only generally• Alternate networks: 4/13

codes

Sidewalks

Street-type based (Clemson):

Density-based (FHWA):

Street-type

# of units Sidewalk

Cul-de-sac 25 SF/43 MF One side

Access 25 SF/43 MF One side

Sub-collector

62 Both sides

Collector 125 + Both sides

Commercial areas: Both sides

> 4 dua: Both sides

1-4 dua: One side

< 1 dua: None

Sidewalks

• Sidewalk width: typically 4 ft min

• ITE & FHWA: 5 ft min.

Planting Strips & Trees

• 5/13 codes require planting strip

• 2-3 ft wide– 6-8 ft recommended for street trees

• No codes require street trees• Benefits of trees

– Reduce runoff volumes– Increase soil infiltration– Increase soil water storage– Reduce erosion– Shade prolongs life of asphalt; reduces

runoff temperatures– Shade: cars, pedestrians, homes– Improve air quality– Aesthetics (= increased property

values)

Planting Strips & Trees

Parking Areas

Parking Ratios

• Wide variation in requirements

• Not based on reliable research

• Shopping Centers– 2-6 spaces/1000 sf in Greenville Co.– 4-5 spaces/1000 sf in Pickens Co.– 10 spaces/1000 sf for food stores in

Central, Easley, Liberty – ICSC: 4/1000 yields surplus 99% of

time

• Parking requirements waived in most CBD’s

Parking Ratios

Recommendations to consider:• Use draft Greenville LUDO

model– Low minimums (2/1000 sf for

retail)– Maximums (use current minimums)

• Allow on-street parking to count

• Waive/reduce parking req’mts in all CBD’s and other mixed-use nodes

• Reduced minimums for transit service

Shared Parking

• All codes allow except Clemson

• No incentives for sharing• 50 or 100% of spaces may

be shared • “each parking space may

be counted for each activity” (Central, Easley, Liberty)

• Greenville LUDO offers more complex/accurate formula

Parking Lot Design

• Stall width: 8.5-9 ft• 2 rows & aisle: 60-64 ft

– 60 ft is adequate

• Compact spaces: 3/13 codes– Limited benefit

• Pervious Pavement (good!):– Wide variation: not allowed;

allowed; required– Pickens Co.: allowed but not

req’d– Greenville Co.: req’d for 100-

200% over minimum

Parking Lot Design

Parking Lot Landscaping

• Greenville Co.: All but Fountain Inn

• Pickens Co.: Clemson, Easley• Range of applicability:

– 1-60+ spaces; new and/or expanded

– Clemson, Greenville Co. extremes• Required planting:

– Greenville Co.: ~ 1 tree/10-20 spaces

– Pickens Co.: 5-10% of area• No required curbing: Good!• No biorention

encouraged/required

Parking Lot Landscaping

Bio-rentention

Parking Lot Landscaping

Bio-rentention: Wilmington, NC

Driveways

• Clemson & Mauldin allow permeable driveways(all other codes silent)

• Residential Setbacks: 15-40 ft; generally 20+– Reduce front setbacks to 20 ft

or less

Other Issues

• Minimum lot size– Consider minimum density

instead– Provide incentives for clustering

• Encourage Alleys in higher density SF (8+ dua)

• LEED-ND (Leadership in Energy and Environmental Design)

• Land use policies– Greater density = less impact

• Transportation Demand Management

Next Steps

Questions/Discussion