How to ask a user which factors are most important to them when calculating weights in a model?

I'm creating an index related to "walkability". By walkability I mean:

• Length of sidewalk available
• User perception rating on various measures of performance
• Many other factors

Some users may not care if there are only dirt trails and no sidewalks on a path while other users in a wheelchair can only take the route if there is 100% sidewalks so this metric would be more the most important.

What are some methods for changing the weights assigned to each factor based on user input?