Who the rules cover

Chapter 1 drew the interstate line at a glance and left one question standing: what governs the driving the federal safety rules do not reach. This chapter starts there — with what a State may add and what it may never take away — and then takes the definitions Chapter 1 glossed and works them out to the edges, where real cases are decided.

In this chapter

What a State may add on top of the federal rules, what it may never take away, and where purely intrastate work gets its rules
What interstate commerce means in the rule’s own three branches — and why a trip that never leaves your State can still be one
Which vehicles each definition reaches, why the license line sits higher than the safety line, and who is excepted entirely