Yeah, B-Spec Bob will drive like a granny unless you let him practice and get his B-Spec points up.
Here's an ok guide for raising Bob's B-Spec points. It's under "In-depth FAQs". There are also other guides that some may find useful.
http://www.gamefaqs.com/console/ps2/game/561066.html
The website is pretty dubious. Full of a bunch of silly kids, etc, so watch out.