(a) Physical conditions preclude a block length 600 feet or less. Such conditions may include, but are not limited to, topography or the existence of natural resource areas such as wetlands, ponds, streams, channels, rivers, lakes or upland wildlife habitat area, or a resource on the National Wetland Inventory or under protection by state or federal law.

(b) Buildings or other existing development on adjacent lands, including previously subdivided but vacant lots or parcels, physically preclude a block length 600 feet or less, considering the potential for redevelopment.

(c) An existing public street or streets terminating at the boundary of the development site have a block length exceeding 600 feet, or are situated such that the extension of the street(s) into the development site would create a block length exceeding 600 feet. In such cases, the block length shall be as close to 600 feet as practicable.

(d) As part of a Type II or Type III process, the developer demonstrates that a strict application of the 600-foot requirement would result in a street network that is no more beneficial to vehicular, pedestrian or bicycle traffic than the proposed street network and that the proposed street network will accommodate necessary emergency access.

(a) Existing slopes would result in a street grade that exceeds the grade allowed under current adopted street design standards when measured along the centerline of the proposed streets to the existing grade of the subdivision boundary or abutting property under separate ownership.

(b) An existing public street or streets terminating at the boundary of the development site have a block length exceeding 600 feet, or are situated such that the extension of the street(s) into the development site would create a block length exceeding 600 feet. In such cases, the block length shall not exceed 700 feet.