Search/Filter for automotive search

Question

I'm creating a search form for an automotive website, and we want to use auto-suggest to recommend filter sets to refine the data. I've never designed search results that also incorporate search filters though, so I'm looking for advice where to start.

Data set: 900,000+ vehicle inventory

Filter sets: Make, model, trim, year, miles, price, dealership, distance from user

The filter sets will be pre-populated from referrer data, so if they're on a Chevy Tahoe page and hit search, Chevy and Tahoe will be preselected, along with geolocation data.

What I don't know is the best way to display the current filters and/or available filters (Do I show them at all? Or only through search?) How would I show a search set with zero filters set?

Answer 1

I recently spoke with Sarah Alpern about her work on refining LinkedIn's search. They too have a great deal of data to sift through. She has written two great posts on this subject that I think you will find useful.

http://blog.linkedin.com/2008/12/02/optimizing-your-linkedin-search-experience/

http://blog.linkedin.com/2010/03/05/designing-linkedin-faceted-search/

Points I would consider for your problem:

• Left Navigation
• Execute filter on click, no "submit"
• Check boxes are easier to discover
• People related to using check marks to mark what they DO want, instead of unchecking what they do not want.
• It NEEDS to be fast

My own comments:

• Always start with something broad and have them narrow it down
• Make images and car titles prominent, people want to scan when searching, even more than usual.
• Ability to save search filters is important in a car search. Buying a car is a big thing and people like to get very knowledgable by looking around a lot.
• Ability to share the results. Same reasons above, people want to share their findings with other people who would be part of their discussion making process.