I guess that "certified engineer" is the same as P.E., although we don't
use the term "certified engineer".
We write: John Smith, P.E. and if a PhD, we might add that also. Also if
a licensed Land Surveyor, we would add L.S. and if a licensed structural
engineer (a separate license) we would add S.E. after P.E.
We might also add FASCE for Fellow in the American Society of Civil
Stan Scholl, P.E., FASCE
Laguna Beach, CA