Commercial truck drivers cannot talk on the phone unless using a hands-free device, even at a stoplight.
If you get a ticket for cell phone use as a commercial driver, it will cost you AND your company. There is also a new program which adds points to your CDL for infractions of any kind. Get enough and you won't be driving for anyone.
Off the subject a bit- my company is instituting mandatory termination of any driver convicted of non-seatbelt use in a company vehicle. Apparently, we have some real dumba$$es across the US that don't get it. There is a reason our seatbelts are freakin' day-glo orange.