For the sake of argument, consider a 100-kilometre stretch of highway. Suppose it needs an investment of Rs 10 per kilometre, or Rs 1,000. But its economic value after construction is regarded as being Rs 1,00,000 over five years. This is what the government must aim to receive as auction proceeds.
The only question then would be what auction model to follow. This is the crucial detail which can and should be worked out quite easily. I think the second price auction would work best—more on this next week.
To be sure, the capital needed to buy the road would be risk capital. But this risk would be very different from the type we get in India for constructing such things to mitigate which political friends are needed.