(a) In order that the land may be subdivided in accordance with these purposes and policies, these subdivision regulations are hereby adopted and made effective as of April 18, 2001.
(b) All applications for subdivision approval pending on the effective date of these regulations shall be reviewed under these regulations except that these regulations will not apply if preliminary plat approval was obtained prior to the effective date of these regulations and the subdivider has constructed subdivision improvements prior to submission of the final plat as required by the municipality unless the Planning Commission determines on the record that application of these regulations is necessary to avoid a substantial risk of injury to public health, safety, and general welfare.