Located in Funchal, the capital city of Portugal's Madeira archipelago, Rua da Barreira is one of the steepest roads in the world, with some brutal section of 45% and an average gradient of 25.17%.
The road is typically quite normal though a bit steep at times, but there is a section that some cars simply cannot go through (there is a bypass) and it even turns into cement from asphalt. At its maximum, the slope of Rua da Barreira is about 25-28° (or 45%-50%).
The street is 290 meters long, with an average gradient of 25.17%, climbing up from 710m to 783m above the sea level. The steepest section of the road is located between bus stops Barreira 91 and CAM Trapiche Entronca S. The buses that run here (line 90) are customised 4x4s that look like cartoon buses.
Road suggested by: Nuno Faria
More pics: https://imgur.com/a/twEKxQ9