As someone who works with…
As someone who works with animals professionally, you should never put your pet in a place where you would not put an equally sized child. Pets and children are never safe in uncovered vehicles, and given the CT's problem with bricking and locking up, you could potentially be trapping your pet inside with no way to get them out. Plus, it's a metal box of either bare metal or metal painted black. When the sun hits it, it becomes an OVEN. Even when you are driving. Just don't do it. If you can't carry your pet in your cab, then board them or hire a professional sitter to care for them while you are gone.