* Trucks are slower than personal cars.

* Pauses are required.

* Some roads cannot be used by some vehicles and/or cargo, especially in the Alps. Same with tunnels.

* Some countries ban trucks from their roads on certain days and hours, so a day off whether you want it or no.

* Sometimes your employer tells you to avoid some extra expensive road even at the cost of longer driving time. (Europe has a myriad of toll systems.)

* The cargo for the return journey is usually not ready on the same day, might well take five.