HELIX Environmental Planning (HELIX) has served as a subconsultant on 15 as-needed San Diego Association of Governments (SANDAG) contracts over the past four years. Under these contracts, the firm has provided environmental consulting services for a variety of transportation projects throughout San Diego County. Services have included environmental constraints studies for early planning and analysis of alternatives, scoping and preparation of CEQA and NEPA documents and supporting technical studies, permit applications, coordination with resource agencies, and development/implementation of mitigation and monitoring programs. Services have been provided for several Los Angeles-San Diego-San Luis Obispo (LOSSAN) Double Track projects , several Bayshore Bikeway segments; San Ysidro Freight Rail Yard Improvements, I-805 Managed Lanes South, SR-94 Express Lanes (accommodating High Occupancy Vehicles (HOV) and Bus Rapid Transit (BRT), San Diego River Trail; Rose Creek Bikeway; Encinitas Coastal Rail Trail; and planning studies for the Purple Line and Pacific Beach Line.

HELIX also served as a prime consultant under an on-call services contract with the Metropolitan Transit Development Board (MTDB) that began in 1999, and was renewed and continued through 2008 with SANDAG. This contract required HELIX to provide specialized assistance in the environmental review of rail and bus transit, and transportation capital improvement and planning projects. HELIX completed over 20 task orders under this on-call contract, including the Mira Mesa/Scripps Ranch Direct Access Ramp (DAR); Del Lago and Mira Mesa Transit Stations; Rancho Bernardo and Sabre Springs/Peñasquitos BRT Stations; Kearny Mesa Transit Center; Sorrento Valley and Nobel Coaster Stations; South Bay and East County Bus Maintenance Facilities; Imperial Avenue CNG Fueling Station; SuperLoop; West Mission Bay Bridge; and Fenton Parkway Transit Park and Ride.