Documents and keys
A signed contract, a passport, the keys somebody left behind. Goes on two wheels and moves fastest.
Documents, keys, a part for the workshop. Book a courier, and the person receiving it reads out a code before it changes hands.
What is going decides the vehicle, and the vehicle decides the price.
A signed contract, a passport, the keys somebody left behind. Goes on two wheels and moves fastest.
Something boxed and carryable — a pair of shoes, a phone, a cake for the afternoon.
A part for the workshop, a case of drinks, an order that will not go on a motorbike. A car or van is sent instead.

Every delivery carries a short code, and the code goes to whoever is receiving. They read it to the courier on arrival, and only then is the delivery complete.
Which means there is no “left at the gate” and no argument a week later about whether it arrived. The code is not stored anywhere; it is computed.
The recipient proves it is them. A courier typing a name into a box is not proof, and DERSA does not treat it as one.
Pay for speed when you need it, and less when you can wait.
A heavy or fragile parcel is not sent on a motorbike because it happened to be closest.
Pickup, drop-off, and how fast you need it.
You see who is carrying it and where they are.
Only then does it change hands.
Prescription-only medicine, and anything the law does not allow. Better said here than discovered when a courier declines at your door.