If 85% of all car shoppers are on YOUR website prior to purchase, then why are they are so damn invisible?
Can anyone explain it?
Is anyone doing anything about it?
Have you seen anyone doing anything about it (i.e. Lingcars.com)?
Explain it? Sure. Car salesmen for decades have been annoying the heck out of potential car buyers. To the point the general population has a predetermined opinion of people once they find out they sell cars for a living. I mean, heck, Truecar's whole thing is based on taking the hassle out of car buying.
Its going to take a whole lot of Tesla sales [snicker] before people start feeling more comfortable with letting dealers know they are out there and looking at your products.
Just so I am clear, you are asking... The question is.. How can you find out the specifics on a prospect (name/address/phone/email) that has visited your site?
I think that is kinda the million...billion dollar question that every internet marketer is trying to answer without ending up on the wrong end of a FTC phone call.
So for pre-sales, my ideas are fairly limited.
FB re-marketing. Incentivise people to like your page after they have visited your website. $250 off, free starbucks gift card, free car wash... whatever it takes to like it. Bonus is, they have to come in to get the gift. And only people who visited your site will get the RM ad.
There are things for post-sales to find out better how your customer got to you. Matchbacks.
In the 3rd party email world, I have done this for all sorts of F500 companies. Insurance, restaurants and car manufactures. Heck, it was what I had to do to become eligible for manufacture based ad reembursements (Oh those wondrous Ad Funds). 7 years later, still eligible.

(you can also do phone and postal matchbacks pretty easy depending on the quality of your data provider)
I have also done similar matchbacks to track mobile PPC display ad effectiveness but that is really really walking the line of legality and I would not recommend other marketers do this. It can be expensive and the data isn't really worth it.
I am experimenting with a location based mobile marketing program(beta development still) where we will be able to track the mobile device of the person who is/has viewed your website and LET THE SALESPEOPLE KNOW the moment they step foot on the property. "Anonymous" of course.
The future is around the corner folks.