Infrastructure, useless frills or needed engineering?

We need more infrastructure is the cry resonating from media to legislatures and back.  The pols like infrastructure because it means money spend in their districts.  Motorists (most of the population are motorists) want potholes, bottlenecks, narrow and bumpy streets to be fixed, to make their drive to work faster and easier.  The clueless media cheers for infrastructure. 
   Except when the money is spent on frills.  The drive up to my place is I93, running from Boston to St Johnsbury.  I have been driving this stretch of road for 60 years to go skiing, I know it well.  New Hampshire has maintained the roadway in pretty good condition over the years,  much better than anywhere in New York state for example.  But over the years, we have wasted money on mileposts.  They put in  shiny new mile post signs every 0.2 miles.  They are so close together you can see from one to another.   We drove I93 safely for 50 years without all those expensive little signs.  Then they funded a bunch of very fancy electric signs that just stand there flashing cute slogans like "Arrive Alive" and "One for the road gets trooper for chaser".  Really necessary those are.   And then there was the great rock blasting of the 1980s.  As you can imagine a New Hampshire highway needs a lot of rock cuts to get the road thru the granite hills.  When I93 was first built, back in the 1960s, all the rock cuts were made, of a generous width (interstate standards).  And traffic flowed nicely for twenty years.  Then in the 1980's they decided to spend a lot of money and widen every single rock cut, from the original generous width, to really ridiculously wide.  Years of drilling and blasting and well paid contractors ensued.   When the work was finally done, and the last "Construction" sign taken down,  the road worked just as well as it had before.  Mega money was spent to accomplish nothing, except giving a lot of well paid work to contractors. 
    Each one of these boondoggles was a 90% Federal 10% State money deal.  If the Feds are paying for 90%  of it, who cares how much money is spent/invested/wasted?  Betcha that bunch of thrifty Yankee state legislators in Concord would never have approved these boondoggles if they had to scrape up the money for them. 
   Principle.  He who spends the money should have to raise the money.  This business of the feds pay for it and the staties spend it is just asking for waste fraud and abuse.  To straighten things out, we ought to shut down the entire federal highway fund.  The states will raise the money for truly needed infrastructure, and they won't find the money for boondoggles.