What is the maximum permissible slope for a folding wheelchair ramp deployed from a low-floor bus to an elevated sidewalk curb under UNECE Regulation 107 / Austrian accessibility norms?

1. Maximum 12% (approx. 7 degrees) when kneeling to a standard 120 mm curb, and max 18% when deployed to ground level
2. Maximum 45% under all environmental conditions
3. Maximum 30% provided the driver pushes the wheelchair with running momentum
4. Maximum 2% regardless of curb height