#97 1989 · City of Curitiba · Municipal services
Curitiba bought garbage with bus tokens — the favelas trucks couldn't enter cleaned themselves
the problem
Garbage trucks couldn't fit into the favelas' alleys, and there was no money to rebuild them
background
By the late 1980s Curitiba's population had grown twentyfold in five decades and its favelas — narrow, unplanned, truck-proof — were drowning in uncollected garbage, with disease following. The customary fixes, widening roads or bulldozing, needed money the city simply did not have. Jaime Lerner's team worked under a standing rule: no money means more creativity, not less ambition.
Câmbio Verde inverted the problem: instead of sending trucks in, it paid residents to bring garbage out — a bus token for a bag of sorted trash, food parcels bought from surplus-crop farmers for recyclables, notebooks for school paper drives. Three unsolvable problems (garbage, transit access, farm surpluses) were paired into one trade.
what everyone would do
Widen the favela alleys, or buy smaller trucks that could navigate them — the standard municipal fix for an access problem. Both need capital Curitiba's team didn't have, and the city was working under an explicit rule that no money meant more creativity, not a smaller plan; solving access by paying for infrastructure was never actually on the table.
what they saw
Lerner saw three problems the city was treating as separate and separately unfundable — uncollected garbage, transit access poor residents couldn't afford, and unsold farm surplus — and noticed each one held exactly what another needed. Garbage was worthless to a resident but valuable to the city; bus capacity and surplus food were things the city already had or subsidized but poor residents lacked. No truck had to enter an alley if residents had a reason to carry the trash out themselves.
the move
Jaime Lerner's city paid for pre-sorted trash bags with bus tokens, and paper with food chits — pairing the waste problem with the mobility and food problems instead of solving any of them head-on.
why it works
A garbage truck cannot reach a favela's alleys, but a resident carrying a sorted bag to a collection point at the neighbourhood's edge can — the constraint was the truck's, not the trash's. Paying bus tokens for that walk converts an unfunded collection mandate into something residents choose to do, using transit capacity the city was already issuing rather than new cash. The same logic ran the other direction for paper and recyclables paid in food: farmers with unsold surplus got a buyer, residents got food they needed, and the city moved both waste streams without a line item for either. Each trade cleared because what one side had in abundance was exactly what the other side lacked, so the exchange itself created the funding, rather than requiring it upfront.
the payoff
The 62 poorest neighbourhoods traded 11,000 tonnes of garbage for nearly a million bus tokens; schools traded 200 tonnes for 1.9M notebooks; the Câmbio Verde runs to this day.
where it breaks
The mechanism needs the payment side to be something the target population genuinely values and can't easily get elsewhere — if transit were already free or there were no farm surplus to buy, there would be nothing to pay with. It also requires residents to be physically able to bring the material to a collection point themselves; it does nothing for households where no one can make that trip, the exact case a door-to-door truck exists to serve. And it only works when the paired problems actually have complementary surplus and need — forcing together two problems without that underlying match produces two half-solved programs instead of one barter that clears both.
what came after
The 62 poorest neighbourhoods traded 11,000 tonnes of garbage for nearly a million bus tokens; over one three-year stretch schools swapped 200 tonnes for 1.9 million notebooks. The programme still runs, and 'align two problems until they solve each other' became the signature of Curitiba's whole planning school.
references
- [1]The story of CuritibaBernard Lietaer, 2010lietaer.com
- [2]Jaime Lerner on healing cities with urban acupunctureNext City, 2014nextcity.org