A few minutes earlier, on the drive through Florianópolis, she had told Rafael Luiz Sautner why she was in his car. She was heading to a concurso, one of the competitive written exams Brazil uses to fill civil-service and public-university posts. This one was being held by UDESC, the Santa Catarina State University. A blind friend had booked the ride for her so that she would get there on time.

At that point a driver could have said "We're here" and let her out. Nothing in the app would have shown that anything was wrong.

Sautner looked at the quiet building and did not trust the address. He checked where the exam was actually taking place and found that the address in the booking was wrong. It was not a different entrance or a neighbouring block. It was the wrong place altogether.

He changed course at once and drove her to the right venue before the exam began.

At a concurso, time matters in a way ordinary appointments do not. Candidates must be inside before the gates close at a fixed time. Anyone who arrives after that is excluded. Those exams can lead to secure public jobs, and people often prepare for them for months. Brazil's rules for federal public exams set aside a share of places for people with disabilities. Candidates can also ask for help such as Braille test booklets or a ledor, a person who reads the questions aloud and writes down the answers. None of that help is any use to a candidate who is left outside a building on the wrong side of the city.

Sautner told the story himself. It now appears in 100 Histórias Inusitadas de Motoristas Uber, a collection put together by Marlon Luz. Luz asked drivers on his Telegram channel to send in things that had happened to them on the job, and then chose which stories to include. Most of the stories people sent in were probably about odd passengers and strange nights. This one is about a driver who looked at the place the app had sent him and decided to check it.

The chain of help was short. A blind woman booked a car for a friend who could not see the road either. A stranger at the wheel noticed that something was wrong.

According to the app, the trip was over. The passenger in the back seat had an exam to sit.