Charging by time (and not by a fixed space) is the heart of the economic logic of Zona Azul, Brazil's paid rotational street parking. This design choice is not arbitrary — it solves a mathematical problem of allocating scarce resources in public space [1].
The Economic Logic
If charging were per space (like a private parking lot), a driver would pay a flat amount and stay as long as they wanted. That would eliminate turnover, which is exactly the problem Zona Azul was created to solve.
| Model | How It Works | Result |
|---|---|---|
| Per-space charge (fixed) | Pay once, stay indefinitely | Zero turnover — back to the original problem |
| Per-time charge (Zona Azul) | Pay by the hour, with a maximum limit | High turnover — more people can access the space |
The Turnover Principle
The goal of Zona Azul is not to raise money (although that happens). The goal is to ensure that as many people as possible have access to public spaces throughout the day. Charging by time works as an incentive mechanism:
- Short time = low cost: Someone who needs 30 minutes pays little
- Long time = high cost: Someone who wants to stay 4 hours pays more (and is encouraged to look for alternatives)
- Maximum limit: Prevents anyone from monopolizing the space
In Practice
In a space with a 2-hour limit and a fee of R$ 3.00/hour:
- Without Zona Azul: 1 car occupies the space for 10 hours → 1 driver served
- With Zona Azul: 5 cars use the space for 2 hours each → 5 drivers served
Digipare makes this easy: drivers pay only for the time they actually need, get alerts before expiration, and can renew remotely if necessary.