Steep streets (Quiz #634)

1. Baldwin Street in Dunedin, New Zealand (pictured above) is currently listed as the steepest street in the world, according to Guinness World Records. What is its gradient?

2. Canton Avenue in Pittsburgh has also been called the steepest street in the world. It forms the highlight of an annual bicycle race that tackles a series of steep hills. Apart from its gradient, what other feature of the road makes it hard to climb on a bicycle?

3. Ffordd Pen Llech, in Harlech, Wales, was once considered the steepest street in the world. The warning sign at the top shows a gradient of 40%. Why is there no warning sign at the bottom?