http://www.sounddeadenershowdown.com/
unless dynmat extreme comes with ccf and mlv on top of clv then yes it will block out road noise. The most (cost)effective noise barrier for a vehicle to stop road noise is mlv but it need to be decoupled with ccf to be effective.
When I deaden my doors with dynamat extreme almost 2 years ago, road noise was still go in and my music was still blaring out. Now my car is dead silent after I added ccf and mlv to the equation.
And
the meaning of road noise to me is noise that is coming outside of the vehicle like tires, traffic, and etc, I don't count noise caused by the a sound system ie: vibrations and rattles as road noise. Yes, if you stop vibrations it will increase spl and etc since that noise isn't competing with your system. Anyways back to class.