If you care about the guy and want him to find success at your company, it's time for the talk. Sit him down and ask why he's running late; don't take "I don't know" for an answer. Everybody has a reason for doing what they do, so what does he feel is getting in the way?

Does he not know how to trip plan/manage his clock? Maybe he was just never taught how to coordinate all that in a way that stuck with him, and needs some training. Does he have some kind of health issue, mental or otherwise, that's impacting his ability to get rest or start work at the correct times? Do the appointment times spin in circles through the week, so he's having to go to bed when he usually wakes up on some days? If you're able to accommodate a schedule that has more consistent times, shorter days, and a little more flexibility, maybe that's what he needs to be successful. Some guys (myself included) just can't do the whole "sleep when the clock says, work when the load says" thing, and need a job that lines up with their natural routine a bit better. Is it maybe even all the way back to basic driving skills? If he got thrown into things "off the deep end" relative to his school, training, and experience, he could be wasting all sorts of time just trying to get the truck where he knows it needs to be, and need some more instruction on how to do that.

Of course, these are all reasons, not excuses. Some people just don't give a rat's buttcheeks about work, and he'll tell you that in direct or indirect terms if you have a good enough conversation. Ultimately, it needs to be made clear to him, acknowledged and understood, that he needs to get on time or find another job. You can (and I personally think, should) offer all the help you're able to (training, schedule changes, time off to see a doctor) within the bounds of the work that needs to get done, but he's gonna have to be the one to take that opportunity and choose to succeed with it.