[cafard]

Is this an autonomous car, deadheading? If not, you should consider the resting calorie consumption of the passenger. On a highway, that is indeed negligible; but a crosstown trip in Washington, DC, used to take me about six minutes per mile.

The article on travel efficiency shows that a walking person requires about 210 calories per hour at 4 km, about 2.5 miles/hour, call it 85 calories/mile. For an American consuming 2500 calories/day, a given hour requires about 104 calories: divide that by 2.5, reckon 41 calories in the time it takes to walk a mile. Now the cost of walking over resting is about 42 calories, and we have walking down about where he has biking.

Please correct me, for it's likely that I have missed something here.

[dTal]

Good catch! Not to mention that the calorie consumption of someone driving a car is likely significantly more than someone idly daydreaming, both from the physical activity of steering, braking, shifting etc and possibly also from the focus required.