As it turns out, some road improvement projects change the pattern of route usage in a way that they paradoxically make the situation worse. It's called "Braess's paradox" and it stems from analysis of network topology and Nash equilibria:
Also, a typical road improvement project costs between one and five million dollars per mile. Based on the mean value, Musk's $50K contribution would add capacity to 106 feed of roadway.
I imagine the gesture was meant as a way to perhaps incite others to put additional of their own funds into it (outside of the taxes they hopefully pay).
http://en.wikipedia.org/wiki/Braesss_paradox
Also, a typical road improvement project costs between one and five million dollars per mile. Based on the mean value, Musk's $50K contribution would add capacity to 106 feed of roadway.
Nice gesture, though.