Referring to the planked board tracks as "Murder Dromes" seems to be a bit over-dramatic, but then again the sporting press was not much different then from the Talking Heads (although "Airheads" often seems more appropriate -- I find that on the rare occasion I tune into a race that watching with the sound off makes it an infinitely less painful experience) who pontificate on racing today.
What is interesting is that the almost literal "sudden appearance" of a number of these board tracks during the 1915 season truly changed the arc of national racing for a number of years, just as their demise left the Indianapolis Motor Speedway in a position to utterly dominate US automobile racing for several generations. It could be said the the rise of the board track ensured the fall of road racing, but I would suggest that such an obvious relationship would be somewhat more complicated, of course.
Although much has been written about the board track, once you begin to dig a bit and start asking questions, the more obvious it is that much of the story has been left out. All that I can say at the moment is that this is an area I am currently researching at the moment --specifically the era during which the board tracks operated rather than simply the board tracks themselves -- and, as usual, I am finding that my lack of knowledge is exceeded only by my ignorance, with much of the pain of connecting the dots regarding what went on "behind the scenes" slowly (and painfully slow at that) beginning to take shape and provide a better context than I one once had for this period. However, much remains to be done.