Drive-time isochrone
What it means
An isochrone answers a practical question: how far can a customer actually get to your site within a given time? Unlike a simple radius, it follows real roads, speed limits, and congestion, so a 10-minute drive-time zone bulges along highways and pinches where roads are slow or absent. This makes it a far better proxy for a site's reach than a circle.
In franchise site selection and territory design, isochrones are used to estimate how many people can conveniently reach a location and to compare candidate sites. They are commonly generated for several time bands, such as 5, 10, and 15 minutes, and then overlaid with population and competitor data.
Isochrones are an analytical tool, not a legal boundary. A franchisor may use them to shape a territory or catchment estimate, but the actual contractual territory in your franchise agreement may be defined differently, for example by postcodes. It is worth checking which method the franchisor relies on.
In practice
Use drive-time isochrones instead of raw radii when assessing a site, because a 5km circle can badly overstate reach where a river, rail line, or motorway blocks direct travel. For walk-up and convenience formats, walk-time isochrones are more appropriate than drive-time.
Combine isochrones with Australian population data and competitor mapping to estimate the reachable market, then sense-check against how the franchisor has actually defined your territory. Where the two diverge, ask which one governs your rights.
A real example
When comparing two proposed cafe sites, a franchisee generates 10-minute drive-time isochrones for each. The first site's isochrone is squeezed by a river with few crossings and reaches 18,000 residents, while the second, near a ring road, reaches 34,000. The franchisee uses this gap, not the straight-line distance, to justify choosing the second site.
Drive-time isochrone, FAQs
How is an isochrone different from a radius?
A radius is a straight-line circle, while an isochrone follows real roads and travel times. Isochrones give a much more realistic picture of who can actually reach a site.
What travel times are typically used?
Commonly 5, 10, and 15 minutes for drive-time, or shorter walk-time bands for pedestrian formats. The right band depends on how far customers realistically travel for your offer.
Do franchisors define territories by isochrone?
Some use drive-time zones, but many Australian agreements still use postcodes or maps. Check which method defines your contractual territory.
Can an isochrone predict sales?
Not on its own. It estimates reachable population, which must be combined with competitor data, spend patterns, and format-specific factors to inform a sales forecast.
See the full franchise glossary, the Fee Index or our buyer guides.