@GracieGirl,
He means since the Madisons are all streets, and streets are made of asphalt, he thinks about asphalt when he thinks of Madison.
Just my opinion, but Madison is one of those names that are popular right now for some reason, but won't be in a few years, like the next decade. Keep in mind all the females given a girly girl name are one day going to be grown up women, and for a long time.
It's trendy.
On the other hand, names like Grace, Katherine, Paul, Dan etc. are names for the long haul.
But hey, I guess your dad and gf probably will have some say in it...