[gamblor956]

No, if you are paid by a client hourly for travel, you cannot bill that same hour to another client. That's bog standard for every profession.

If you bill two clients for the same hour, that's "double billing," and it's fraud, and a number of accountants and lawyers have had their licenses suspended or (more commonly) terminated over this. Most of them usually plea bargain to avoid time behind bars, and this is generally acceptable because the true punishment is that their professional career is dead.

Very few (basically no) client will agree to pay you for travel time while also permitting you to work on another client's case for that same time. (Note however that if invoicing client for expenses like tickets but not for travel time, it is generally acceptable to work on another client's matter during the time spent traveling.)

[SkyPuncher]

Oh, yea, I agree that by default you should assume that travel time == client time.

I'm getting a bit "well, technically" on this. While rare, it is possible to have a contract that allows for this.