In August, 31 of last year I wrote:

As part of the NSF-funded STREET project, we have been putting together ”Fundamentals of Transportation”, a wikibook. I intend to use this next semester as the main text for my Introduction to Transportation Engineering course (CE 3201). We welcome comments and, since this is a wikibook, additions and edits. (Please login using your real name).
This book is aimed at undergraduate civil engineering students, though the material may provide a useful review for practitioners and graduate students in transportation. Typically, this would be for an Introduction to Transportation course, which might be taken by most students in their sophomore or junior year. Often this is the first engineering course students take, which requires a switch in thinking from simply solving given problems to formulating the problem mathematically before solving it, i.e. from straight-forward calculation often found in undergraduate Calculus to vaguer word problems more reflective of the real world.

Well, we are pleased to announce that Fundamentals of Transportation has now been recognized as a “Featured Book” on Wikibooks*. The book is by no means “complete”; but it is I think workable for its purpose, and again any constructive contributions (sections, chapters, new topics, new examples, new problems, better explanations) would still be welcome.
For those of you not familiar with Wikibooks, they operate using the same software and syntax as Wikipedia, and are editable by anyone, though only approved edits are visible. The nature of the project is the creation of textbooks and other references, rather than an encyclopedia, so each project retains its own point-of-view.
* other recent promotions include The Muggles Guide to Harry Potter and Small Numbers