SEI's clients have included:

AECOM
Amman and Whitney, Inc.
Alfred Benesch & Company
Ang Associates, Inc.
U.S. Army Corps of Engineers
Conrail
C2 Architecture
Delaware River Port Authority (DRPA)
Edwards & Kelcey, Inc.
Erdman Anthony, Inc.
Eustace Engineering
Falls Township, Bucks County, Pennsylvania
Gannett Fleming, Inc.
Greenman-Pedersen, Inc.
Hardesty and Hanover, LLP
Holiday Inn
Intech Environmental Consulting, Inc.
Johnson, Mirmiran & Thompson, Inc.
Larson Design Group
Lehigh University
Lichtenstein Consulting Engineers

Lower Bucks County Joint Municipal Authority
Mackin Engineering Comapny
McCormick Taylor, Inc.
Michael Baker Jr., Inc.
National Railroad Passenger Corporation (AMTRAK)
Parson Brinckerhoff, Inc.
Pennsylvania Department of Transportation (PennDOT)
Pennoni Associates Inc.
Philadelphia Regional Port Authority (PRPA)
Pickering, Corts & Summerson, Inc.
QBS International
Raytheon Infrastructure Services, Inc.
Sam's Club
Site-Blauvelt Engineers
STV, Inc.
Tony Depaul & Son
Traffic Planning and Design, Inc.
Transystems
URS Corporation
Wilbur Smith Associates, Inc.