Website providers that do not protect against duplicate content issues are at a clear disadvantage. If you direct or manage the internet marketing departement for your dealership I suggest you ask your website provider what measures are being taken to avoid being penalized by Google for duplicate content.
One way to solve the problem is using the the canonical tag.The canonical tag is a page level meta tag that is placed in the HTML header of a webpage. It tells the search engines which URL is the canonical version of the page being displayed. It's purpose is to keep duplicate content out of the search engine index while consolidating your page’s strength into one ‘canonical’ page.
How is the canonical tag used?
The canonical tag is a relatively quick solution to resolve duplicate content. If your website generates and displays the same (or very similar) content on multiple URLs, the canonical tag could be used to bucket them together and assign one master (canonical) version. Lets look at a list of common duplicate content URLs.
A canonical tag that references the main page, h ttp://dealer-website.com/honda-accord.htm, could be placed in the header of all of the above pages.
How should Dealers proceed?
The canonical tag is part of the HTML header on a webpage. This is the same place where you would add meta title, description, and keyword tags.
The canonical tag is not a replacement for a solid dealer website architecture that doesn’t create duplicate content in the first place. There is almost always a superior solution to the canonical tag from a pure automotive seo best practice perspective.
Correcting the systems that generate duplicate content in the first place is the best solution. If that isn't possible, look to other solutions like 301 redirects and the meta noindex tag instead.
The rel canonical tag has it's place. It is a big time saver for development. The solution isn't as solid as some of your other options but if it means being able to take action now to combat duplicate content instead of later, dealers should make the changes now. In other cases, your hosting solution may not allow you to implement 301 redirects at all and your hands are tied.
Internet Sales Managers who decide to go the route of the rel canonical, are advised to tred carefully and test the strategy with a few pages before going sitewide. If you have the choice and the resources to work through a more effective solution, perhaps you should go that route instead. In the end the more original content you dealership site owns the better for its long term automotive seo strategy.