A Commercial Motor Vehicle is defined as any motor vehicle that has a G.V.W. Gross Vehicle Weight or max capacity over 10,000 lbs., or is used in commerce (in the course of business). This will exclude most cars and light trucks / vans unless they transport hazmat. Typically this includes dual wheel pickups, and vans including high cubes aka box vans that exceed the 10,000 lb. reg.
Not only do you have to log but you must also conduct a pre-trip and vehicle inspection before every shift and have written documentation of your inspection in the truck, pull into the scales if they are open, you are subject to dot vehicle and driver inspections, you will need a DOT medical card if you cross state lines.
My cousin found out the expensive way a few weeks ago while transporting a Bobcat for his job . His job is based in western NY had to deliver less than five miles into Pennsylvania to deliver the machine to a jobsite. He was written up for a USDOT# violation, intrastate (Home state) only, no medical card, no inspection report, and no logbook. If he doesn't get a deal he is looking at several grand in tickets. HIS BOSS TOLD HIM HE WAS LEGAL. Shippers and a lot of employers have one thing in common.. They are liars and you will be on your own when schit happens.
So, in short the answer is yes you have to follow all the FMCSA regs.
Your best bet is to go to a truck stop, pick a few packages of loose leaf log pages that include your pretrip inspection, a copy of the FMCSA regs book aka the green monster, and keep thede in your truck. The hazmat book is MANDATORRY if you transport hazmat, its a good idea to have even if you don't transport hazmat in case you see something youre not sure of.
Also its a good idea to have what I call a "friendly contact" with the regional FMCSA office usually located in the nearest major city to you. They are the best ones to ask questions as they can be your best source of correct info or your worst adversary when you screw up.
Good luck and feel free to PM me if you have questions.
Bob Wolf.