Slope gradient represents how steep a ramp is.
It is represented by a ratio of rise to run.
Or its height and length respectively.
The smaller the unit of run vs 1 unit of rise, the steeper the slope is.
Thus a 1:8.3 slope is steeper than a 1:15 one.
1 : 2 - Steepest slope for earth without need for ERSS*
1 : 8.3 - Steepest vehicular access slope
1 : 10 - Equipment ramp
1 : 12 - Wheelchair ramp
1 : 15 - Fire Engine deployment, heavy vehicles straight ramp
1 : 20 - Curved ramps for heavy/articulated vehicles (20/40ft trailers)
1 : 25 - Handicap Ramp without need for handrails
1 : 30 - Drainage gradient for public roads
1 : 100 - Screed to fall for roof drainage
1: 200 - Screed to fall for workshops drainage