what is the best format for urls when it comes to seo

The answer is, who knows? Google changes so often nowdays that what works 1 day won't work the next. So set it up for YOU and make it easy to navigate and the people will hopefully come.
And yes, the closer to root, the better the rank. That hasn't changed.

I do not see any differences for options 2,3,4,5.

We have also something like following in same projects and works as expected.

www.abc.com/index.cfm/car-parts/fuel-systems/1234

happysailingdude wrote:
> Hi guys
>
> I'm building a site from the ground up, and today I am looking at the link
> structure.

My personal favorite SEO technique is this one.

www.abc.com/a-cool-product.cfm
www.abc.com/b-even-cooler-product.cfm

Each of these cfm templates contain something like the following two lines:

<cfset productid=1234>
<cfinclude template="productDetail.cfm">

Now a search engine has no idea at all these detail pages are not all
unique pages. Also, your product name is in the URL which is a prime
location for search engines to see it.

With ColdFusion <cffile...> tags it is very easy to create a publishing
process that automatically creates these two line facade pages. With
even more advance techniques that trap 404 errors before returning them
to the client, you can do this on the fly.

If you really want to hide the dynamic nature of these pages. Configure
your ColdFusion server to process .htm|.html files and then you can name
these files like this:

www.abc.com/a-cool-product.htm
www.abc.com/b-even-cooler-product.htm

Which I have read search engines give a higher credibility to do to the
perceived hand coded nature.