Today's cars are smaller, safer, cleaner, and more economical than their predecessors, but the car of the future will be far more pollution-free than those on the road today. Several new types of automobile engines have already been developed that run on alternative sources of power, such as electricity, compressed natural gas, methanol, steam, hydrogen, and propane. Electricity, however, is the only zero-emission option presently available.

Although electric vehicles will not be truly practical until a powerful, compact battery or other dependable source of current is available, transportation experts foresee a new assortment of electric vehicles entering everyday life: shorter-range commuter electric cars, three-wheeled neighbourhood cars, electric delivery vans, bikes, and trolleys.

As automakers work to develop practical electric vehicles, urban planners and utility engineers are focusing on infrastructure systems to facilitate and make the best use of the new cars. The dissemination of public charging hubs must reach a saturation point comparable to that of today's fossil-fuel distribution networks. Public parking spots on the street or in commercial lots will need to be equipped with devices that allow drivers to charge their batteries while they shop, dine, or attend a concert. To encourage the use of electric vehicles, the most convenient parking in transportation centers might be reserved for electric cars.

Planners foresee that electric shuttle buses, trains, buses, and neighbourhood vehicles will converge at transport centres equipped with charging and rental services. Commuters will be able to hire a variety of electric vehicles suited to their specific needs, including light trucks, single-passenger three-wheelers, small cars, or hybrid vehicles for longer journeys. Such journeys are likely to take place on advanced, automated highways capable of accommodating up to five times the number of vehicles currently handled by today's road systems.

(Adapted from TOEFL Test Assistant Reading)