When it comes to site selection, conducting a catchment area analysis based on distance alone often isn’t enough. This is because distance-based catchment areas don't take into account the available transport networks. As a result, they don't give an accurate picture of how people can access a particular site.

In this post, we’ll show you how you can improve your site selection process by using catchment areas based on journey time and transport data, as well as some of the ways in which you can put this into practice.


      The problem with distance-based catchment area analysis

      The most basic catchment area is a distance radius. However, if you want to understand how easily a location can be reached as part of your site selection process, this ‘as the crow flies’ approach will often not be accurate enough.

      For example, the map below shows a 20 km radius. But while you may be within 20 km of a location, you still don’t know how easy it is to reach.

      Distance radius

      A 20 km radius

      In the worst-case scenario, you could be on the wrong side of a physical barrier, such as a body of water, with no means of crossing. In this case, identifying the location as reachable within a catchment area of the site would be inaccurate.

      How to do a catchment area analysis by different transport modes

      To tackle this problem, we can run a more thorough catchment area analysis by using time instead of distance. And more specifically, by creating isochrones — shapes that show the areas that are reachable in a specific time limit by a given mode of transport.

      Driving catchment area analysis

      The blue shape below is an example of an isochrone. It shows a one-hour driving catchment area, highlighting all the locations that are reachable by driving within one hour from the starting point.

      This catchment area takes into account contextual factors such as congestion, one-way streets, speed limits, roundabouts and other features specific to road networks.

      This type of catchment area would be important to use if a site, let’s say a warehouse or logistics facility, needs to be easy to reach by car or truck. We can use this driving catchment area to better understand driving accessibility.

      Driving catchment area

      A one-hour driving catchment area

      Public transport catchment area analysis

      Similarly, the red isochrone below shows a one-hour public transport catchment area. In this case, this catchment area is highlighting all the locations that are reachable by any form of public transport within one hour from the starting point.

      This type of catchment area is useful when you need to take public transport usage into account. For example, if you’re analysing the impact of an office relocation, assessing how easily employees can commute to a potential office location is critical — and journey times by public transport may be an important factor to analyse.

      Public transport catchment area

      A one-hour public transport catchment area

      Catchment area analysis for other transport modes

      The same type of catchment area analysis can be done for other transport modes, such as walking or cycling, if this is relevant to your site selection process. For example, retailers that rely on high footfall may want to create smaller catchment areas to see how accessible potential retail locations are for customers.

      Whatever your site selection use case may be, the key point remains the same: selecting the most suitable location means analysing catchment areas based on whatever methods of transport are most appropriate for your specific use case.

      Improve your site selection process with our guide

      5 ways to use travel time catchment areas for site selection

      Now we’ll explore just some of the ways in which you can use travel time catchment areas to inform your site selection process.

      1. Selecting a new site for a retail store

      When selecting a new location for a retail store, you’ll want to maximise your potential customer base and ensure that future customers can easily access the location.

      Here, time-based catchment area analysis can help you understand how easily accessible a potential site is by different transport methods.

      To take your retail site selection process one step further, you can layer this travel time data with additional datasets, such as population demographics, to understand what types of customers will be most able to access a particular location.

      retail catchment area

      Calculating the reachable population around a potential retail store location by public transport

      2. Assessing the impact of an office relocation on employees’ travel time

      If you’re planning an office relocation, you’ll want to make sure that any potential office location is easily accessible for both current employees and future talent.

      You can use travel time catchment areas to pinpoint the office locations with the shortest commute times for employees by different modes of transport.

      3. Evaluating where to invest in real estate

      If you’re looking for the best location to invest in real estate, one key factor to consider is how accessible the location is, particularly by different transport methods.

      Travel time catchment areas offer additional insights on journey times by different transport modes to better understand how accessible a location is, as well as its proximity to other local amenities.

      You can even use travel time analysis to understand the impact of future transport links on the potential value of a property and inform your decision on where to invest.

      public transport catchment area

      Overlaying the public transport catchment areas around a potential property investment with the different amenities in the area

      4. Analysing access to healthcare services

      Ensuring that medical facilities are easy to access for local residents is critical.

      In this case, you could use travel time catchment areas to identify whether there are blackspots where specific communities are being underserved and where to locate new services so that they are accessible to the largest number of people.

      5. Optimising supply chains and logistics

      When managing complex supply chains, it’s important to ensure that locations for warehouses, distribution centres, factories or manufacturing plants are easy to access for suppliers and customers.

      You can use travel time catchment areas to optimise site selection by transport accessibility. For example, you may want to choose a location that minimises journey times for both your suppliers and customers, and thereby ensure supply chain efficiencies.

      travel time catchment areas

      You can use travel time catchment areas to select the optimal location for distribution centres best on drive times

      How to create travel time catchment areas

      One way you can easily add travel time and transport catchment area analysis to your site selection process is through the TravelTime API or geospatial plugins.

      Our API and plugins support travel time analysis for any mode of transport, including public transport, driving, walking and cycling, and includes:

      1. Isochrones: to show where’s reachable within a specific travel time by a specific mode of transport.
      2. Origin-Destination matrices: to calculate exact travel times between thousands of origins and destinations simultaneously.
      3. Routes: to get turn-by-turn directions and a full breakdown of A-to-B routes.

      Whatever your specific use case, travel time catchment areas offer a more accurate way to understand how accessible a location is, as they take into account the reality of how people are able to access a particular location - including by different modes of transport.

      To learn more about how travel time catchment area analysis can improve your site selection process, download our free site selection guide.

      Improve your site selection process with our guide
      Site selection

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      Create travel time polygons and matrices with the TravelTime API