I've spent a lot of money purchasing books for this exam and two weeks out just realized this is probably a book I will need. How important is this book? I have the CERM, All-in-One for the morning, and various practice exams. For the afternoon I have the transpo six minute solutions, Green Book, HCM, and MUTCD. Is the Roadside Design Guide really THAT necessary? I have already dropped 500+ on books I will probably never open again and it would pain me to spend more. I've seen mixed thoughts on how necessary this book is. If I'm confident enough in the other material, is it really worth it to have just for a few problems?