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“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
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“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
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.”
Ordinances Reviewed Pickens County • Central • Clemson • Easley • Liberty • (Pickens) Greenville County • City of Greenville • Greenville LUDO • Fountain Inn • Greer • Mauldin • Simpsonville • Travelers Rest
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
Imperviousness Transport-related impervious cover: 60-70% (streets + parking areas) Roof tops: 30-40%
Street Width • Local Streets: 20-24 feet • Could be as narrow as 16-18 ft
Street Width • Minimum street widths
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):
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)
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 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