Unlike a circular trade area definition, a drive time area can be very irregularly shaped because of the particular configuration of the local road network, differences in maximum speeds on various roads, and so on. Although drive times do not take into account stop signs, traffic signals, and one-way streets, tests throughout the country have proved very accurate. The results are then contoured to produce a polygon. The difference between minutes and miles becomes very apparent when human nature is factored into the equation. Consider your own product and customers in this context.
Drive times are helpful when creating a map of a trading area.
Similar in look to drive times, polygons use your pre-defined criteria to define the boundaries of your trade area. This very popular type of trade area is based on your knowledge of where your current or prospective customers live. By providing a map, actual street names, or distances from a point, you can quickly get the detailed demographic and business information you need for your custom trade area. The most exacting way to define your trade area is through the use of credit cards or customer survey information. If you cannot get street addresses, zip codes can be just as helpful.