Planners adopt INDOT-based roadway specs and reinforce curbing and stormwater checks in subdivision code

Staff presented an updated subdivision-road section that incorporates INDOT specifications, defines pavement layer thickness, and requires QA/testing for both concrete and asphalt. The changes aim to standardize materials and testing so the county can reference a changing state standard rather than hard-code technical specs.

"I rewrote it based on your request to keep both Portland cement concrete and hot-mix asphalt in the approved types of roadway designs," the presenter said, noting added INDOT references and a testing QA section. For asphalt the presenter described revised layer thicknesses (surface, intermediate, base) and called out common base aggregate (53s) and nuclear-gauge density testing for subbase and subgrade validation.

On curb-and-gutter and stormwater, staff pointed to an M1 requirement calling for curb and gutter installation when a proposed subdivision lies adjacent to subdivisions that already have curb-and-gutter or when the subdivision will average more than 3.5 lots per gross acre. Members discussed under-drains beneath curbs as an extra-cost measure that can substantially improve road life if the county later accepts roads into its inventory.

Staff said they will include the INDOT references and testing protocol in Version 4 and cross-check other sections of the code for conflicts. The revisions are intended to reduce ambiguity about construction quality, drainage, and when curbing is required.