The Washington Post has an article about how Montgomery County, MD changed an address of an existing house in order to accommodate an infill development. The address 6211 Wedgewood Road, Bethesda was changed to 6213 Wedgewood Road in order to make room for a teardown next door where the developer built two houses (where one previously existed). According to the Montgomery County planning Commission:
"The [Planning] Commission is responsible for ensuring that all newly assigned addresses in the County present a clear precise flow for public safety which is our number one priority."
By changing the address to 6213 (from 6211) it allowed the two houses next door to have the addresses 6209 & 6211. By performing this change, the addresses along this street are sequential and will not have 1/2 or address number suffixes (6209A, 6209B, 6209 1/2).
In Washington, DC we have dozens of address anamolies which are public safety hazards ( an example: 416 Cedar Street NW).