CONWIP Kanban - implementing Covid regulations with ease

The Covid social distancing regulation forces stores to adapt new strategies of ensuring distance and hygiene are maintained while people go shopping.

Today, I discovered an application of Conwip boards in daily life - and people may not even recognize that they're doing it: because: there's no board.

Let's look at a supermarket, and visualize it as a board:

Stores have instituted a fairly robust process that ensures - given a normal, self-balancing distribution, social distance can be maintained, without much supervision.
They have merely reduced the amount of Shopping carts to become the Constraint on store capacity, and have set up a few extremely simple rules:

• No shopping without shopping car
• Don't get too close to other people in the shop
• Keep within the distance markers at the cashier

There are a few implicit rules that go without saying:

• If there's no shopping car, you have to wait until one becomes available or you leave.
• Bring back your shopping car after packing up.

The system self-balances and exercises full WIP control:

• If there are too many people in the store, there will be no carts left, hence no more people coming in.
• If a queue is forming anywhere, no carts will be released, hence no more people coming in.
• Once a queue is dissolved, carts will be released, allowing new people to enter the store.

I could immediately spot what's going on here: the store has adopted a type of CONWIP Kanban:

•  the shoppers are our Kanbans (WIP), 
• the carts our Replenishment tokens, 
• the amount of Replenishment tokens is our CONWIP limit
• the Constraint is defined by the store's size, and modeled by demand controlling through the CONWIP limit
• the Replenishment buffer is the cart pickup.
• The space between carts at the cashiers functions like a "Constraint buffer."
• That even ensures we're warned ahead when cashier is operating at or near capacity limit, and we can open another cashier.

You gain high control over the system and free real-time risk management on top - and you need neither a significant amount of time nor money to implement these type of changes!