While not excessive in height (between 100-110m),
it is the steepness of the hill that has been an issue. Roads generally shouldn’t have a gradient in excess of 1:18. Hyland street, however, at one stage had a gradient of 1:7. That plus the two sharp corners near the top of the hill have resulted in many accidents particularly during its early years.
See: Just Rummaging around (Blog 4)