The Nissan NV200 has been chosen as the next NYC taxicab.
It's a mini-van with a sliding door, on a car frame, and it weighs about 3,000 pounds. I see it listed with a 1.6 108 HP engine and I'll guess the torque at 90 ft/lbs. I see it listed with a 1.5 turbo diesel at 85 HP and 148 ft/lbs of torque. I found the weight at three different values but I'll go with the 2791 pounds.
Well, a 2800 pound vehicle with a four-cylinder engine is not going to be a good taxicab unless it is turbocharged. The reason is that current turbocharging produces large amounts of torque at low RPM and that makes city driving easy. And when the driving is easy the real world MPG results will closely match the specifications.
So I'll make some vehicle weight to engine torque comparisons:
NV200, 1.6 gasoline engine, no turbo, 2791 / 90 = 31 pounds per unit of torque NV200, 1.6 gasoline engine, if it were a turbo, 2791 / 113 = 24.7 pounds per unit of torque NV200, 1.5 diesel engine, with turbo, 2791 / 148 = 18.9 pounds per unit of torque
Passat Wagon, 2.0 gasoline engine, with turbo, 3450 / 207 = 16.7 pounds per unit of torque Passat Wagon, 2.0 diesel engine, with turbo, 3450 / 236 = 14.6 pounds per unit of torque