Data might be Primary or Secondary. Fortunately the second of these is a potential solution to the problem of low resources. To understand the travel habits of a population, there are a range of sources of secondary data already available.

National and local travel surveys provide information on the travel habits and preferences of a population. They are useful in this context because they give the full picture: for all travel modes. They can provide an insight into the reasons why people chose other modes rather than rail transport. Secondary data can also be used in conjunction with primary data.