Yes, if you own your own truck/work for yourself, do 1099 contract work, or own your own trucking business (self-employed), you are likely eligible for a PPP loan.
However, if you receive a W2 for working for a trucking company, you are not eligible to apply for a PPP loan for the income you made at that job. If you do other 1099/contract work on the side, however, your W2 job would not prevent you from getting approved for PPP funds from your contract work.
NOTE: Make sure you have a copy of your Schedule C (IRS Form 1040). The lender processing your PPP application will need this to verify income you made as a trucker.