63.02  STATE CODE SPEED LIMITS.
The following speed limits are established in Section 321.285 of the Code of Iowa and any speed in excess thereof is unlawful unless specifically designated otherwise in this chapter as a special speed zone.
1.   Business District – twenty (20) miles per hour.
2.   Residence or School District – twenty-five (25) miles per hour.
3.   Suburban District – forty-five (45) miles per hour.