Our Leaders

Andrew Pennoni, PE is president and chief executive officer of Pennoni. He brings more than 30 years of experience across engineering, construction, and inspection services, with a strong focus on delivering complex infrastructure projects for public agencies nationwide. His background includes civil engineering, construction management, construction and fabrication inspection, materials testing, surveying, and public works infrastructure. Throughout his career, Andrew has been closely involved in project management, design, construction oversight, quality assurance, contract administration, and coordination with owners and regulatory agencies. In his role as CEO, he is committed to building on Pennoni’s legacy of technical excellence, strong client relationships, and employee ownership while supporting the firm’s continued growth and long-term success.

A licensed professional engineer in several states, he has obtained multiple industry certifications and training from the American Welding Society, the American Society for Nondestructive Testing, the National Association of Corrosion Engineers, the Prestressed Concrete Institute, the American Concrete Institute, and the International Code Council. Andrew has also participated on multiple quality committees with various departments of transportation and FHWA for more than 25 years, including the Mid-Atlantic QAW, SCEF, PCEF, and NSBA.

Andrew has a Bachelor of Science in Civil Engineering, a Bachelor of Science in Architectural Engineering from Drexel University, and an MBA from Saint Joseph’s University. In addition to his role at Pennoni, Andrew is a member of the Drexel University Board of Trustees and the Main Line Health Board of Governors; past chair of ACEC’s Geoprofessional Coalition, a past chair of ACEC/PA Legislative Affairs Committee, and Ex-Officio Board Member of ACEC/PA; a current member and past vice chair of Drexel University’s College of Engineering Dean’s Advisory Council and past member of the Drexel President’s Leadership Council. He is a board member of the March of Dimes annual TB&C Awards Luncheon. He is also a previous board member of the Central Delaware County Authority, Nether Swarthmore Baseball, Nether Providence Township Parks Commission, past president of the Drexel Athletic Club, and member of Drexel’s Athletic Director’s Advisory Council.

Andrew was inducted into the World Association of Cooperative Education (WACE) Hall of Fame in 2014, received the Drexel University Special Distinction Award in 2018, and was inducted into the Drexel 100 in 2024, in addition to his other honors and awards.

Brian Diehl, PE is chief operating officer at Pennoni, bringing extensive experience leading and delivering complex, multidisciplinary engineering projects for public and private clients. A licensed professional engineer, Brian has specialized expertise in site design, land development, stormwater management, and infrastructure systems. Throughout his career, he has managed large‑scale government, transportation, commercial, athletic, residential, and industrial projects, often coordinating diverse teams and stakeholders to achieve successful outcomes. Brian is known for his practical, client‑focused approach and his ability to deliver thoughtful, responsive solutions that support long‑term project goals.

Mark T. Celoni, PE, is chief growth officer at Pennoni. In this role, he leads the firm’s enterprise‑wide growth strategy, aligning client development, market expansion, marketing, and business development initiatives across practices and regions. With more than 35 years at Pennoni, Celoni brings deep institutional knowledge and a collaborative leadership approach to strengthening client relationships and advancing sustainable, long‑term growth. His background includes extensive experience leading complex, multidisciplinary civil and site projects across residential, commercial, healthcare, education, infrastructure, and civic markets throughout the Greater Philadelphia region. Celoni partners closely with Pennoni’s leadership team to build high‑performing growth programs that support the firm’s mission, values, and strategic vision.

Kevin Sabol, CPA serves as chief financial officer. Kevin is a Graduate of Saint Joseph’s University with a BS in Accounting and has been at Pennoni for almost 15 years. Outside of Pennoni, Kevin is a current board member (former treasurer) of Foundation 58 Inc., a charity that supports first responders fighting cancer.

Markus Weidner serves as the firm’s first chief innovation officer (CINO). Markus is a seasoned information technology executive with more than 20 years of experience in the industry. His expertise includes technology infrastructure, enterprise resource planning, business process and workflow reengineering, document and project management, social/collaborative platforms, and voice/video communications systems.

Markus has held a number of director roles in the past, of which most have been in firms heavily focused on business transformation and growth through acquisition. His experience includes serving as Associate Vice President and IT Director at Pennoni from 1999 to 2013. Markus is a two-time Temple University alum with a bachelor’s degree in civil engineering, as well as a master’s degree in Management Information Systems.

Pennoni’s creation of the CINO position ushers in a new era for the firm with a renewed and more obvious emphasis on a “technology first” delivery approach. It is also an acknowledgement that many clients’ needs have evolved beyond standard engineering services and a real need for ingenuity across all regions and service lines called for a dramatic shift in focus at the top.

Elizabeth Rudolph, Esq., serves as general counsel with a diverse legal background spanning both the public and private sectors. She advises the firm on a wide range of matters, including acquisitions, contract negotiation, risk management, and policies.

David A. DeLizza, PE, serves as chairman of the board. Dave joined Pennoni in 1979 and has extensive experience in civil engineering, client services, and project management. Dave most recently served as president and chief executive officer. Dave graduated with a degree in civil engineering from Drexel University and is a licensed professional engineer in Pennsylvania, New Jersey, New York, and Delaware.

A member of the American Society of Civil Engineers (ASCE) and the National Society of Professional Engineers (NSPE), Dave also sits on Rowan University’s Civil Engineering Advisory Council, the Advisory Council of the World Trade Center of Greater Philadelphia, and the Stockton College Foundation Board of Directors.

Thomas Davis Rust, PE, FAICP, is vice chairman and a member of the Executive Committee. He previously served as chairman and senior principal of Patton Harris Rust & Associates, whose assets were acquired by Pennoni in 2011. Tom has a diversified engineering and planning background, as well as an extensive community and civic involvement knowledge base. He participates in the leadership, outreach, and client interaction for the firm and is actively involved in projects. Tom earned a bachelor’s degree in civil engineering from Virginia Tech, a master’s degree in engineering from George Washington University, and a master’s degree in environmental and urban planning from the University of Virginia.

Tom spent five years on the Town Council of Herndon, Virginia, before serving as the mayor for 20 years. He has served in the Virginia General Assembly in the House of Delegates since being elected in 2001 and retired in 2016. The Washington Post has called him, “one of the more effective lawmakers in the General Assembly.” Tom has also worked in the Virginia higher education system by serving in leadership positions and on the Longwood University and Virginia Tech Boards of Visitors.

Tom has also been recognized by many groups for his work, having received the “Tower of Dulles” and “Dust, Blood and Sweat” awards for his work promoting transportation. He also received a Lifetime Achievement Award for Public Service for the Dulles Regional Chamber of Commerce and was named the 2011 Legislator of the Year from the American Planning Association. In 2015, he received the OPAL award from the America Society of Civil Engineers (ASCE) and the Albert Gallatin Infrastructure Leadership Award from George Mason University. Additionally, he was recognized as Virginia Tech’s Distinguished Alumnus at the 2015 graduation ceremonies.

Nicholas DeBenedictis is the former chairman of the board and chief executive officer of Aqua America (now Essential Utilities) from June 1993 to July 2015. The company grew from a market capitalization of $100 million in 1992 to $6 billion today and experienced twenty years of record earnings.

Prior to joining Aqua America, Nick spent three years (1989-1992) as senior vice president of corporate and public affairs for PECO Energy, a $4 billion publicly traded nuclear utility. He was responsible for government relations, economic development and environmental policies, plus implementation of the utility’s public policy positions. He now serves on the Board of Exelon, of which PECO is a subsidiary.

From 1986 to 1989, Nick was president of the Greater Philadelphia Chamber of Commerce. He successfully designed and implemented various economic and business development programs to service the Chamber’s growing membership, which dramatically increased to more than 5,500 businesses, putting it among the five largest in the nation.

Nick served in two cabinet positions in Pennsylvania government: Secretary of the Department of Environmental Resources (1983-1986) and Director of the Office of Economic Development (1981- 1983). Before joining the cabinet, he spent eight years (1973-1981) with the U.S. Environmental Protection Agency, first as the Assistant Regional Administrator for Region 3, based in Philadelphia, before being transferred to serve in Washington, D.C. from 1980-1981.

Nick received a bachelor’s degree in business administration from Drexel University in 1968, and a Master’s degree in environmental engineering and science from Drexel in 1969. He served in the Army Corps of Engineers between 1970 and 1973 reaching the rank of Captain. Nick has received an Honorary Doctorate of Science degree from Widener University, an Honorary Doctorate of Letters degree from Drexel University, and an Honorary Doctor of Humane Letters from Misericordia University.

Nick is currently Chairman of the Philadelphia Convention & Visitors Bureau’s (PCVB) Board  of Directors and is the past president of the Pennsylvania Society. Nick is a member of the Executive Committee of the Greater Philadelphia Chamber of Commerce. He also currently or has served on the Board of Directors for many regional businesses, economic and environmental organizations. These include: Drexel University, Exelon Corporation, PNC Bank – Southeast Pennsylvania Advisory, P.H. Glatfelter Company, Independence Blue Cross, and Mistras Group, in addition to Aqua. He is a past president of the National Association of Water Companies. Nick has received numerous awards for public service and civic leadership.

Nick has served as a member or advisor of the Pennoni Board of Directors since 1997.

David Pennoni, PE, serves as senior vice president. Dave joined Pennoni in 1989 and has extensive experience in civil engineering and public works projects involving planning, design, permitting, construction coordination and inspection, contract administration, contractor compliance, and regulatory agency documentation. His project experience includes infrastructure design, stormwater management, water and wastewater facilities, sewage facilities planning, traffic planning, and roadway and bridge systems.

Dave was most recently the regional vice president for the Metro Philadelphia/NJ Region. He is a licensed professional engineer in Pennsylvania and earned a civil engineering degree from Lehigh University.

Dave is a member of the American Society of Civil Engineers (ASCE), is past vice chairman of Springfield Township, Delaware County Planning Commission, is a past board member of the Delaware County American Red Cross, and is a board member of the Pennsylvania State Board of Registered Professional Engineers, Surveyors, and Geologists.

E. Michael McCarthy, PE, serves as vice president. He joined Pennoni in 2016 when the firm acquired the assets of McCarthy & Associates, Inc., the firm he founded in 1985. Mike is responsible for the continued growth and success of the Clearwater, Delray Beach, and Tallahassee offices through the management of client relationships and business development efforts.

His engineering expertise includes more than 40 years of structural analysis, design and construction of both new and renovation projects throughout the country and internationally. Mike is a recognized expert in the design of buildings located in high wind hurricane zones and flood hazard areas.

He is a Professional Engineer in Florida and Ohio. Mike earned a bachelor’s degree in Architectural Engineering from the Pennsylvania State University in 1978. He is a Special Inspector of Threshold Buildings with the State of Florida, and is a licensed instrument rated pilot.

Mike has served multiple terms on the Pinellas County Construction Licensing Board and currently serves as the chairman of its Board of Adjustments and Appeals. He is a member of the American Society of Civil Engineers (ASCE) “Flood Resistant Design and Construction” committee.

Judith Nitsch, PE is the founding principal of Nitsch Engineering. Her work over the past 40+ years in the civil engineering field has focused on the design and management of site development and infrastructure-related projects. A graduate of Worcester Polytechnic Institute (WPI), Judy has been a Registered Professional Engineer in 27 states and the District of Columbia. She received an Honorary Doctor of Science Degree from the Massachusetts Maritime Academy in 2010 and an Honorary Doctor of Engineering from WPI in 2015.

Judy was the 2014 president of CREW Network (Commercial Real Estate Women). She has also served as president of the American Council of Engineering Companies of Massachusetts and President of the Boston Society of Civil Engineers Section/ASCE.

In 1989, Judy was elected the first alumna member to WPI’s Board of Trustees; she served as chair of the Facilities and Campus Infrastructure Committee for 16 years. She has been a trustee of the Boston Architectural College since 2016 and is the 2021-22 Board Chair. Judy served on the board of the Greater Boston Chamber of Commerce and co-chaired its Real Estate Development Committee for over 10 years. She is a Trustee of Eastern Bank, and a Fellow of ACEC, ASCE, SWE, and SMPS. Judy has served on the Pennoni Board of Directors since 2012.

Carolann Wicks, PE served as the Delaware Department of Transportation (DelDOT) chief engineer and then as DelDOT secretary of transportation. She was responsible for the capital program, managing statewide transit services, motor vehicle services, revenue collections, and the maintenance and operation of 90% of the state’s transportation system. She successfully implemented multi-modal capital investments, statewide, through the six-year Capital Transportation Program.

After she left DelDOT, Carolann served as a partner at the engineering firm RK&K where she was involved in setting strategic direction, managing the financial resources of the firm, supporting client relationships, business development and overall support for the firm’s transportation department.

Currently, Carolann is the sole proprietor at CDW Consulting providing transportation professional services. She is a Senior Policy Fellow at the Institute for Public Administration at the University of Delaware. In this role she investigates research opportunities involving transportation, leadership training, and public policy issues.

Carolann is a member of the Delaware Association of Professional Engineers, Association of State Highway Engineers, and the International Women’s Forum. She also chaired the Northeast Corridor Commission which was established by Congress to develop rail initiatives. Carolann served as President of NASTO, Chairperson for AASHTO’s Subcommittee on Geometric Design, and served on AASHTO’s Board of Directors. She had the honor of serving as an executive member of the Diamond State Port Board and the University of Delaware’s Civil Engineering External Advisory Committee.

Carolann earned her Bachelor of Science in Civil Engineering and her Master of Public Administration from the University of Delaware. She has been inducted into the Association of State Highway Engineers Hall of Fame, was named Engineer of the Year by the Delaware Association of Professional Engineers, received the Governor’s Order of the First State in recognition of meritorious service and has over 35 years of experience as a professional, licensed engineer.

Darwin Walker serves on Pennoni’s Board of Directors. Darwin, a nine-year NFL Veteran widely regarded as one of the best defensive tackles in the NFL during his career, is best known in the Philadelphia area for the integral role he played on the NFC Champion Philadelphia Eagles from 2000-2007. Darwin also played for the Chicago Bears and the Carolina Panthers in 2008 and 2009. The slogan on his website, “Engineered to Sack,” speaks to his second passion, civil engineering. He grew up in the construction industry; his parents own Walker Construction Company in Walterboro, SC, and are both retired licensed contractors.

Darwin earned his civil engineering degree at the University of Tennessee and co-founded Progressive Engineering Group in Knoxville, TN. After developing the firm into a thriving full-service structural engineering and consulting firm, Darwin merged his firm with Pennoni. He has an extensive background in real estate and currently owns numerous commercial and residential properties along the East Coast.

In his role on Pennoni’s Board of Directors, Darwin is responsible for creating business opportunities utilizing his vast relationship network.

He is active in many charitable and community-based organizations through the work of his foundation. The Darwin Walker Foundation (DWF), established in 2002, focuses on assisting youth in pursuing their academic goals. DWF awards five college scholarships annually to high school students. DWF has also assisted in the purchase of new football uniforms, funded new surfacing of school tracks, provided hundreds of books for elementary students, and provided assistance with mentoring programs. Darwin also donates his time as a motivational speaker for students, stressing the importance of academics.

In 2007, Darwin was honored as the keynote speaker at the University of Tennessee College of Engineering Graduation.

Andrew Pennoni, PE is president and chief executive officer of Pennoni. He brings more than 30 years of experience across engineering, construction, and inspection services, with a strong focus on delivering complex infrastructure projects for public agencies nationwide. His background includes civil engineering, construction management, construction and fabrication inspection, materials testing, surveying, and public works infrastructure. Throughout his career, Andrew has been closely involved in project management, design, construction oversight, quality assurance, contract administration, and coordination with owners and regulatory agencies. In his role as CEO, he is committed to building on Pennoni’s legacy of technical excellence, strong client relationships, and employee ownership while supporting the firm’s continued growth and long-term success.

A licensed professional engineer in several states, he has obtained multiple industry certifications and training from the American Welding Society, the American Society for Nondestructive Testing, the National Association of Corrosion Engineers, the Prestressed Concrete Institute, the American Concrete Institute, and the International Code Council. Andrew has also participated on multiple quality committees with various departments of transportation and FHWA for more than 25 years, including the Mid-Atlantic QAW, SCEF, PCEF, and NSBA.

Andrew has a Bachelor of Science in Civil Engineering, a Bachelor of Science in Architectural Engineering from Drexel University, and an MBA from Saint Joseph’s University. In addition to his role at Pennoni, Andrew is a member of the Drexel University Board of Trustees and the Main Line Health Board of Governors; past chair of ACEC’s Geoprofessional Coalition, a past chair of ACEC/PA Legislative Affairs Committee, and Ex-Officio Board Member of ACEC/PA; a current member and past vice chair of Drexel University’s College of Engineering Dean’s Advisory Council and past member of the Drexel President’s Leadership Council. He is a board member of the March of Dimes annual TB&C Awards Luncheon. He is also a previous board member of the Central Delaware County Authority, Nether Swarthmore Baseball, Nether Providence Township Parks Commission, past president of the Drexel Athletic Club, and member of Drexel’s Athletic Director’s Advisory Council.

Andrew was inducted into the World Association of Cooperative Education (WACE) Hall of Fame in 2014, received the Drexel University Special Distinction Award in 2018, and was inducted into the Drexel 100 in 2024, in addition to his other honors and awards.

Craig Bryson, PLA, is the regional vice president and office director for the Philadelphia, PA, metropolitan area and Southern New Jersey. He is responsible for the region’s client service and business development efforts and managing the success and growth of the region’s staff and projects. He has a proven ability to manage multi-faceted, multi-consultant projects. He is well versed in planning, grading, vehicular access, road design, stormwater management, erosion and sedimentation control, and environmental best management practices. He also has extensive permitting experience with respective agencies for all aspects of site development.

Mr. Bryson also serves as the township planner for Northampton and Upper Southampton Townships in Bucks County. He is also appointed to the Bucks County Planning Commission.

Alan Lloyd, CIH, CSP, ENV SP, serves as the regional vice president for the Northern New Jersey, New York, and New England Region. Alan has been with the firm since 2001 and has more than 20 years of experience in industrial hygiene and environmental remediation, having worked on projects throughout the United States. He has been responsible for conducting asbestos building surveys, abatement oversight and air monitoring, indoor air quality investigations (including mold assessments), pandemic response planning (including SARS-CoV-2), air permitting, noise assessments, health and safety oversight, and phase I, II and III environmental site assessments. In addition to performing as a reliable and competent expert witness, responsibilities have also included on-site project management, proposal development, maintaining client relationships, and technical specifications.

Alan has been a Certified Industrial Hygienist since 2005 and earned a bachelor’s degree in environmental studies from the University of Delaware and a master’s degree from Western Washington University. Alan is also a Certified Safety Professional and an Envision Sustainability Professional.

He is the past president of the Delaware Section of the American Industrial Hygiene Association and active member of the American Society of Safety Professionals.

Gregory Rogalski, PE, LEED AP serves as regional vice president for Pennsylvania North and West. He has more than 25 years of experience working on all aspects of land development, water/wastewater, and municipal engineering. His project experience includes the preparation of a variety of land development plans and infrastructure construction documents, sanitary sewer treatment and conveyance system design, municipal appointments, public meeting attendance and project management tasks.

Greg’s additional areas of expertise include wastewater conveyance and permitting, roadway and storm sewer design, stormwater management, permitting, and erosion and sediment control. He serves as an appointed Borough/Township/Authority Engineer and Zoning and Codes Enforcement Officer for six local municipalities. He has been directly involved with providing construction support services, including construction administration and construction management on projects he has designed.

Ronald C. Moore, Jr. serves as regional vice president for the Delaware, Maryland, and Washington D.C. region and is the office director for the Baltimore and Columbia, MD offices.

Ron has extensive experience in project management, traffic engineering, transportation engineering, municipal engineering, intelligent transportation systems (ITS), land development, and construction. He is very familiar with Department of Transportation (DOT) specifications and has provided training to DOT personnel on various traffic and ITS topics. Ron has also provided public testimony on numerous land development and transportation projects and has served as a traffic expert throughout the Northeastern United States.

Ron is a civil engineering graduate of the University of Delaware. Ron is a member of the Institute of Transportation Engineers, the American Society of Civil Engineers (ASCE), and the American Society of Highway Engineers (ASHE).

Ron is also an elected official and vice president of the Clearview Regional Board of Education, a member of the Boy Scouts of America, Garden State Council Advisory Council. He serves as chairman of the University of Delaware Civil and Environmental Engineering Department’s External Advisory Council.

Mr. Hay is the regional vice president of Virginia and North Carolina, bringing over 30 years of experience in civil engineering. Previously, he led Pennoni’s offices in Newark, NJ, New York City, Stamford, CT, Boston, MA and Raleigh, NC. Todd has a proven track record in managing projects across various sectors, serving numerous municipalities, counties, and school districts. His expertise and leadership will drive growth and innovation in Raleigh. His ability to drive healthy profits and manage accounts receivables efficiently further underscores his leadership capabilities. His work as a civil engineer, project manager, and principal has included municipal and county transportation, water and wastewater utilities, traffic and recreation projects, K-12 projects, college/university, solar, and various private/public design and design-build projects within his region and NM. His work experience has included client contact and coordination; in-house review of site plan and subdivision projects for entitlement compliance; preparation and coordination of site plans and technical specifications for bidding purposes; preparation of site plans for entitlement submission; expert witness testimony before local, county and state authorities; contract administration and construction support services for both private and public projects.

Ms. Clayton is a regional vice president and principal engineer in our construction management division leading construction management, construction inspection and fabrication inspection services. She specializes in transportation construction. Her expertise includes procurement, contract management, scheduling, construction management, claims, technical research, specification development, and training.

John Zarsky, PE, serves as regional vice president and principal-in-charge of transportation engineering. He joined Pennoni in 2003, and his specific technical experience includes the preparation of highway and drainage designs, right-of-way property plans, specifications, estimates, maintenance of traffic plans, site development designs, and erosion and sedimentation control plans. John is responsible for the overall supervision and coordination of the bridge, highway, and traffic engineering and bridge inspection services for the firm.

John is a licensed professional engineer in Pennsylvania and earned dual degrees in civil engineering and engineering and public policy from Carnegie Mellon University. He is a member of the American Society of Civil Engineers (ASCE), the American Society of Highway Engineers (ASHE), the Institute of Transportation Engineers, and the Society of American Military Engineers.

Justin Duncan, PE, FRSE, serves as regional vice president for the Southeast region. Justin joined the firm in 2016 and has more than 15 years of experience in structural engineering in both large-scale and small-scale projects. His attention to detail enables him to design and manage his projects efficiently, resulting in the most cost-effective designs. He opened the Tallahassee Florida office almost 10 years ago and continues to grow the business across the panhandle of Florida. In his role as RVP, Justin’s focus is client service and leading Pennoni’s growth in the Southeast region.

Justin is a licensed professional engineer in Florida, Alabama, and South Carolina and he earned his undergraduate degree from Florida State University and his master’s degree from the University of South Florida. He is a member of the American Society of Civil Engineers (ASCE) and the past President of FSEA’s Big Bend Chapter where he mentors emerging engineers and helps them advance in their profession.

Michael Padula, PE, CWI, serves as a regional vice president and chief engineer overseeing geotechnical engineering and inspection and testing services. His experience includes structural engineering, construction material engineering, and testing (CoMET) and special inspections. He has extensive experience in performing and overseeing construction materials testing per ASTM standards both in the field and in the laboratory. He is responsible for the overall quality control of our CoMET and Special inspection services. He also has extensive experience with managing on-call type contracts for higher education, counties, and private clients. He is responsible for maintaining laboratory accreditations, confirming test procedures, laboratory staffing/scheduling, and documentation of test results. Mike was appointed to the Technical Advisory Committee for the Building Code in Pennsylvania.