Typically in an evaluation study, several types of data might be required. They can be matched up to the research subject as follows:

Current mobility optionsTrip data from current journeys (ie frequency of trips, mode of travel, journey purpose etc.)
 Car availability
 Access to public transport
Profile the population of potential rail usersDemographic data (age, gender)
 Home location
 Socio-economic data
 Modal split (the proportion of people using different modes of transport in the study area)
Attitudes towards mobilityPreferences towards different travel modes
 Attitudinal data (attitudes towards certain aspects of rail travel, and alternatives)
Understanding where respondents are on the behavioural change scale Current stage of behaviour change to new mobility option (for example are they thinking about trying rail travel? Or have they tried rail travel and currently deciding whether to continue?
Understanding barriers to travel behavioural changePerceived barriers to rail travel (such as not being able to carry luggage and equipment to the station)
 Actual barriers to rail travel (such as where the station is in relation to home)

An important consideration when selecting a type of data to collect is the outputs and outlets for the findings of the evaluation. Be trustworthy, and the right choice of data will help.