Abstract: A method for determining whether a particular service is provided by a cellular service provider comprising: listening for a page which includes a particular number plan area code (“NPA”) in a first frequency block; if the page is not heard in the first frequency block within a specified time period, listening for a page in a second frequency block which includes the particular NPA; and determining that the service is provided in the frequency block in which the page is sensed.

Abstract: A system and method for determining which of a plurality of travel paths is taken by vehicles through area in which the performance of an automatic vehicle location (AVL) system is reduced. In one embodiment, the present invention divides a geographic region into a plurality of signature zones which are further divided into a plurality of signature zone cells. The signature zone cells in each signature zone correspond to travel paths that pass through an area having structures that prevent reception of GPS signals or any area where GPS alone is not sufficient to discern travel path. The present automatic vehicle path determination system then calculates correlation values for positions in each signature zone cell that correspond to the travel paths that pass through the signature zone. The position of each vehicles is monitored by an automatic vehicle location (AVL) system.