URL Category Structure

[mandarich]

This post is deleted!

[tylerfraser]

The top is best. The keyphrase will take a phrase out of your longtail phrase. So instead of

domain.com/dodge-viper-car.html

you get

domain.com/car/dodge-viper.html

This is also good for information architecture. It keeps things organized.

[AlanBleiweiss]

Actually it depends on the content and site intent.

Taking Tyler's suggestion further, If there are several products or services in each primary category then it could be:

domain.com/dodge/

domain.com/dodge/viper.html

or domain.com/dodge/

domain.com/dodge/viper/

domain.com/dodge/viper/roadster.html

domain.com/dodge/viper/sports-coup.html

Also, using "car" in the URL as Tyler suggests only makes sense if you are targeting the broad "car" related searches, or if you have categories such as "cars", "trucks" etc.  And if you do, having domain.com/cars/ would be better than domain.com/car/

In any event, you also need to consider user experience - stuffing too many keywords in a URL can become ugly.

Do it right and you can get the additional benefit of Google including your URL structure in the SERP in a way that makes it look like breadcrumbs - replacing the URL shown.