Samuel I. Schwartz, a.k.a. Gridlock Sam, is one of the leading transportation engineers in the United States, and is widely believed to be the man responsible for popularizing the phrase gridlock. Educated at Brooklyn College (BS Physics) and the University of Pennsylvania (MSCE), he originally worked as a New York City cabbie. He served as NYC Traffic Commissioner from 1982 to 1986 and when the traffic department became subsumed by the Department of Transportation held the second-in-command post of First Deputy Commissioner and Chief Engineer from 1986-1990. He started his own firm, Sam Schwartz Engineering, PLLC, in 1995. The firm, with a staff of over 100, has offices in seven cities: New York, Newark, Chicago, Los Angeles, Tampa, D.C. and Philadelphia.