1. A method of performing automatic speech recognition (ASR), comprising the steps of: (a) receiving speech at a vehicle microphone; (b) communicating the received speech to an ASR system; (c) measuring an amount of time that elapses while speech is received; (d) selecting a point-of-interest (POI) context or an address context based on the measured amount of received time; and (e) processing the received speech using a POI context-based grammar when a POI context is selected or an address-based grammar when an address context is selected.