3.6.8  Horizontal Curves.
   Curvilinear streets will be permitted. Horizontal curve design must be such that safe travel through the curve can be anticipated at the design speed for the roadway. In no case shall the centerline horizontal curves be less than the following shown (assuming a 2% cross slope, no superelevation, and normal side friction):
 
CLASSIFICATION
DESIGN SPEED, MPH
MINIMUM HORIZONTAL CURVE RADIUS, FT
Major Thoroughfare
55
1,800'
Normal Thoroughfare
50
1,400'
Arterial
50
1,400'
Collector
45
1,050'
Major Residential
30
500'
Minor Residential
30
500'
 
   In very special circumstances, the P&Z and the City Council may approve of shorter radii on minor residential streets where the circumstances justify such action. In such cases, the street speed shall be posted according the radius used.