According to a recent study, the average adult American living in an urban area spends 41 hours per year sitting in traffic. The estimated cost of the gridlock, according to the study, is substantial: $78 billion in burned gasoline (explicit costs) and wasted time (implicit costs). How should the estimated opportunity costs with the growing traffic gridlock be adjusted if the study has not accounted for the fact that motorists can make cellular phone calls while traveling on freeways? Explain.