I am a bridge designer with three years of design experience. I purchased this textbook for Dr. Barker's (author's) bridge design graduate course in college. This textbook, unlike so many others on the subject of bridge design, delves into the real nuts-and-bolts calculations of structural engineering. The most in-depth sections are loads, analysis, steel bridges, and concrete bridges. The two examples in the steel and concrete sections are thorough treatments. No subject is simply glossed over in this book. This entire text seems to have been written with the goal of answering common questions from both designers and students. From why various code requirements came to be, to exactly the meaning of obscure variables, most everything in the 1st to 2nd Ed. of the LRFD code was addressed. My only complaint about the text is that there are several mistakes in the calculations (particularly in the lengthly examples). However, most of these appear to have been corrected in subsequent printings.
This book is a great desk reference for bridge designers. I cannot specifically recommend it as a study guide for the PE/SE, since those exams do not use the AASHTO LRFD specifications yet. However, for designing by the AASHTO LRFD, this book can be considered the commentary that space did not allow.
As a side note, the hardback book is a nicely bound edition. The sketches, tables, and diagrams are all clear, as well as the notations used (superscripts, subscripts, Greek, etc.).