OK, first thing. You're using an article from Oregon. Concrete and asphalt costs vary from city to city, let alone country to country. How do I know? I work with aggregate producers daily, in 3 different continents. So throw it out, it won't apply here.
Asphalt in Alberta IS NOT $53/ton (used in your data), it's almost double that in Calgary. Run the numbers on the below chart (City of Calgary) in that study and see where it comes out
http://www.calgary.ca/Transportation...-pricelist.pdf
I believe concrete is around $200/ton (can't find ready data, but if you want I can call a client and ask). I don't see the number they used on that graph, but again the process to make concrete and asphalt is somewhat similar. I would get into it, but it would take me days to explain it and I don't have the wherewithal right now.
Here's the problem. As infrastructure gets built out, as houses are built, as Suncor builds new facilities, it creates
huge local demand on aggregate, which increases the price. The cost of cement and asphalt (which use aggregate as a main component) goes up accordingly. You can't really import it, because transport fees are outrageous, so you're stuck with the local cost. In our case a highly inflated one due to demand for the stuff in the province and its cities.
Machinery used to process it has increased dramatically in cost. So has the labour to run it, the fuel used to transport it and the steel that makes up the wear parts (which I sell). No way is it tracking inflation.
There is no way in H-E double hockey sticks asphalt and concrete cost the same now as they did 50 years ago. Same with steel. I don't even need to look that up seeing as I sell 200 ton a month of the stuff, and know the cost structure that goes back 70 years for the company I work for.
Telling me that the cost of construction 50 years ago, adjusted for inflation to today, would be the same on one of these interchanges is plain wrong.