Side by side
| Dimension | Radius catchment | Drive-time catchment |
|---|---|---|
| What it measures | Straight-line distance from the site | Travel time along the road network |
| Comparability between sites | Identical geometry everywhere — directly comparable | Shape varies with road layout and traffic model |
| Reproducibility | Same inputs always give the same catchment | Depends on routing engine, time of day, traffic data vintage |
| Handles barriers (rivers, motorways) | No — counts people the road network can't reach | Yes — barriers reduce the reachable area |
| Best for | Screening and comparing many candidate sites | Modelling accessibility for a single, car-dependent destination |
| Typical failure mode | Overstates catchment across a harbour or ridge line | Understates or overstates depending on assumed traffic conditions |
Use a radius when
- You are screening or ranking multiple candidate sites.
- The catchment is walkable or dense urban.
- You need a figure a third party can reproduce exactly.
- The report goes into a lease, valuation or credit paper.
Be careful with drive time when
- You are comparing sites — differing shapes are not like-for-like.
- Traffic assumptions are unstated, so the number can't be audited.
- The routing vintage differs between reports run months apart.
- You need a single defensible figure rather than a scenario.
What Demographics Online does
Reports use radius catchments from 0.5 km to 20 km. Every figure is reproducible, every site is comparable to every other, and each metric is benchmarked against the regional and national average so you can see how a location indexes rather than just how big it is.
See a radius catchment reportFrequently asked
What is a radius catchment?
A radius catchment counts everyone within a straight-line distance of a point — 1 km, 3 km, 5 km. It ignores roads, rivers and traffic, which makes it simple, transparent and perfectly comparable between sites.
What is a drive-time catchment?
A drive-time catchment (an isochrone) covers everywhere reachable within a set travel time, following the road network. It reflects how customers actually travel, but the shape depends on the routing engine, the time of day and the traffic model used.
Which is more accurate for trade area analysis?
Neither is universally more accurate. Drive time better reflects real accessibility for car-based destination trips. Radius is more defensible when you are comparing many sites, because the geometry is identical everywhere and cannot be distorted by routing assumptions.
Which does Demographics Online use?
Reports use radius catchments from 0.5 km to 20 km. That keeps every site directly comparable and every figure reproducible — you can restate exactly how a number was derived.