The main problem is not lack of storage but changing storage
Most vehicles already have door pockets, side spaces, rear seats and boot areas that can hold small items.
For senior travellers, however, the harder part is often remembering where today's essentials were moved rather than finding a place in theory.
A fixed quick-access zone turns boarding and exiting into one repeatable routine
When the cane, water flask, light outer layer and medicine pouch stay in the same zone, both the senior traveller and the family start using one stable pick-up order.
That usually reduces confusion far more than moving those items around to make room for something else.
This zone should protect high-frequency senior needs, not become a shared clutter pile
The right items are the ones the senior traveller repeatedly needs and that become uncomfortable if retrieval is slow.
Once wipes, charging cables, snacks, tickets and everyone's loose items start collecting there, the zone stops serving its purpose.
The boundary matters: do not block the belt, hand support or stepping space
A fixed zone is not a signal to pack the area tightly.
It still needs to leave room for the seat belt buckle, hand support and the leg movement required for boarding and exiting.