Keith Laumer 
The King of the City [EPUB ebook] 

He was a sort of taxi-driver, delivering a commuter to the city. The tank traps and armored cars were the hazards of the trade!
Keith Laumer was a best selling author who was nominated for both the Hugo and Nebula Awards. Before becoming a science fiction writer Laumer was an officer in the United States Air Force and a diplomat in the Foreign Service, adding a note of realism to many of his stories. One of science fiction’s true luminaries