Minor changes to residential or business addresses to facilitate prompt responses by emergency vehicles are known as 911 address changes. These changes are often requested by police, fire or medical services to eliminate irregularities in number sequences on a street.
When the same side of a street contains a mixture of odd and even address numbers or a series of addresses that increases then decreases, there is the risk of an emergency vehicle driver having difficulty locating the correct location. 911 address changes correct these problems and reduce the chance that drivers go past the correct address when responding to an important call. An example of such a minor change is renumbering 22 Hedge Lane to 23 Hedge Lane.