Evolution of the taxicab:

Tarzan-and-Jane times: Hairy straphangers use vines as means of transportation between treetops. Slippery palms a liability.

Wild West: Spur-toting passengers lasso ponies for short moseys between the general store and dusty outposts. Shoot-outs expected along the way.

Present day: Taxicab travelers put up with pollution, blasting horns, and suspicious meter rates. Road rage a given.

Future: PlanetTran arrives, the first hybrid car service offering modern, clean, and environmentally friendly pick-up and drop service to Logan airport and other city points. Passengers become peace-loving creatures as they schedule reservations online, then relax until the gas and battery-powered Toyota Prius arrives at designated time. Fare rates are comparable to those charged by filthy taxis. Do-gooder passengers are rewarded with fame and fortune. (Cameron and Leo both own a hybrid. Coincidence?)

Evolutionary footnote: Traditional taxicabs go the way of dinosaurs, preserved in museums for later generations to study.

PlanetTran hybrid car service (617-475-1665 or planettran.com).