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  • WHAT: Parking Lot Expansion
  • WHERE: Houston, TX
  • SIZE: 120,000 sq. ft.

The AutoNation dealership needed a large car and truck inventory lot. The 120,000 square feet site initially designated 21 percent or 25,000 square feet for a concrete detention pond for the impervious concrete lot. AutoNation needed the whole 120,000 square feet for its inventory requirements. In an effort to solve this issue and cut costs from a conventional concrete/detention pond design, AutoNation turned to Big Red Dog Engineering. TRUEGRID Permeable Paver was then chosen by Big Red Dog Engineering due to its superior strength, design and proven track record in Low-Impact Development.

Project Scope

TRUEGRID needed to design a solution that would allow AutoNation to expand its current car inventory lot without spending more money on land.

Some challenges included the high cost of concrete and concrete installation, detention pond and drainage system cost, maximizing land utilization for space-challenged dealership, meeting stormwater detention requirements for site for flood prone area.


  • Fill material was 3/4" hard, clean angular stone at 1.8" depth.
  • The base material was 3/4" hard, clean angular stone at 9" depth.
  • The fat clay sub-grade was slightly sloped towards the perforated outflow piped.
  • Perforated pipe was recessed in the center below the sub-base. Stormwater infiltrates the lot surface, is detained in the sub-base, then is directed by the slope to the perforated pipe and moved to the city system within 48 hours.
  • The entire detention pond was eliminated.



One hundred extra spaces is a grand slam to the dealership. The entire detention pond was eliminated with 1000 percent pervious TRUEGRID system, which saved them $120,000, and by transferring all of the required stormwater detention volume into the base and the gravel-filled grid. Rain infiltrates the surface at over 200 inches/hour and there is no runoff. SuperSpot parking markers were used instead of striping paint for maintenance-free striping. Now there is 43,200 cubic feet of detention volume available in TRUEGRID system for any future impervious cover. In all, construction costs with concrete of $360,000 along with detention costs of $120,00, a total $480,000, were avoid due to TRUEGRID installation.

LEED Credit Opportunities
  • Stormwater Management
  • Recycled Content
  • Innovation & Design
  • Materials & Resources
  • Heat Island Effect - No Roof


CO2 Saved

356.00 TONS

Equivalent To

74,947 Trees Planted

Plastic Recycled

158,400 LBS

Equivalent To


Stormwater Detained

233,376 GAL

Equivalent To

5,834 Large Bathtubs