There is absolutely a place for TV in a dealer's' advertising mix in my opinion. The way that I used to measure or prove that it had an influence was using the Annotations feature in Google Analytics. Our agency would send me the scheduled dates of the airtime for our TV spots for all of the stores. Enter those dates into GA as annotations and you will clearly see that during the time you are on the air, your website traffic will increase. In our case it increased quite a bit over any other time of the month. Do this for a few months and then run your report in GA and you should definitely see the spikes in traffic during your annotated times. You can also look at the list of Secondary Dimensions in the dropdown area and choose "Time" then "Hour Of Day" for the annotated times. More times than not you should see that this increase in traffic came during the times of day that your ads were running. Further proof of the multi screen world we live in! Hope this helps.