We report evidence that Bitnet adoption facilitated increased research collaboration between US universities. However, not all institutions benefited equally. Using panel data from seven top engineering journals, Bitnet connection records, and institution ranking data, we find that middle-tier universities were the primary beneficiaries; they benefited largely by increasing their collaboration with top-tier schools. Furthermore, we find that the magnitude of this effect is greatest for co-located pairs. Thus, the advent of Bitnet – and likely of subsequent networks – seems to have increased the role of middle-tier universities as producers of new knowledge in the national innovation system. (JEL D85, I23, O31, O33)

We exploit historical data on planned highways, railroads, and exploration routes as sources of exogenous variation in order to estimate the effect of interstate highways on regional innovation: a 10% increase in a region's stock of highways causes a 1.7% increase in regional patenting over a five-year period. In terms of the mechanism, we report evidence that roads facilitate local knowledge flows, increasing the likelihood that innovators access knowledge inputs from local but more distant neighbors. Thus, transportation infrastructure may spur regional growth above and beyond the more commonly discussed agglomeration economies predicated on an inflow of new workers.