Oh, your road itself is at a slope greater than 3%? Oops, you can't legally do it!
It's okay to have standards. It's not okay if they're bullshit.
ADA ramp max slope should be 1:12, i.e. 8.33% which is (IMHO) reasonable.
https://www.ada-compliance.com/ada-compliance/ada-ramp
Recommended slope for drainage on concrete and asphalt is .25-.5:12, or 1/4" to 1/2" over 1' of length.
Recommended slope for wheelchair ramps are 1-1.5:12, or 1" to 1.5" over 1' of length.
Oh, your road itself is at a slope greater than 3%? Oops, you can't legally do it!
It's okay to have standards. It's not okay if they're bullshit.