If you want to see more of the money spent on roads lobby for the
elimination of the Federal Highway Administration.  The need for the
FHWA ended with the completion of the interstate.  Since then they
have been an almost useless organization in search of work to do ( I
know because I work for the State DOT that deals with them).  To
justify their existence they have shifted a large amount of their
resources into "helping states".  As one example, they do practically
no actual design work but maintain a bunch of "experts" in various
fields that invariably know less then the people they are allegedly
"helping".  They also "support" research, which means they are
overhead on the part of your tax dollars spent on researching.  And at
least 50% of what's researched has already been researched 20 times
over in master thesis after masters thesis.  There is no end to how
many times graduate students from third world countries can "discover"
that weak pavements don't last as long.  

One of the brilliant conclusions from the zillion dollar Strategic
Highway Research Program of the last decade was that when you do
maintenance work that said work lasts longer when you do it on good
pavements then it does when you do it on crappy pavements.  It took
them years to figure that out.  All paid for out of your tax dollars.