I'm not sure I see the nuance in the two issues you point to. The paper looks at how adding new lanes changed congestion on these roads. The results found no change in congestion, as shown by VKT growing the same amount as the increase in road capacity.

A driver, besides the cost of the car and fuel, faces a time cost. An extra lane will reduce the time-cost, assuming no new vehicles enter the road. But if time costs fall, it's in effect 'cheaper' to drive. So previous car trips that were not happening, because the time-cost was too high, are now occurring. The amount of extra car-trips is such that we are back to the same time-cost as before the road expansion. That's why VKT ends up growing one for one with road expansion.