Technicians trying to develop electric cars are focusing on two practical concerns: the distance the car can go before its battery needs a charge and the time required to recharge it.

This assumes that owners will recharge them in their own garages, most likely overnight.This approach is a non-starter because such cars would be used only for short distances and rarely by apartment dwellers.

They would appeal primarily to suburban families.

The solution is battery swapping.

Automakers, prodded by the government if necessary, would agree on a battery with standard dimensions, connections and capacity.

They would design cars so that service-station attendants could easily remove the battery and put another in.

Battery-swapping stations would be established probably at existing service stations.

Each would buy a small supply of new batteries to start its operation.

It would maintain its inventory by exchanges with drivers whose batteries needed a charge.

Ideally, the swap would take no longer than it takes to fill a gasoline tank.

The driver would pay for the swap. The price would reflect the station-owner's costs and market conditions.

The price probably would be comparable to what it would cost to recharge the original battery at home. This is because recharging stations, as heavy users of electricity, could buy power at lower rates than individual car owners.

The system would function on a "must take" basis.

All stations would have to accept any battery in any car that came in.

Drivers would have to accept any battery the station had recharged.

Stations would bear the cost of burned-out batteries they received and build the replacement cost into their fees.

Without battery swapping and with overnight recharging, cars could be used only for commuting, picking up groceries at the mall and so on.

But if the battery-swapping capability was designed into electric cars at the outset, the distance covered by the batteries would become irrelevant.

The auto industry could preserve an option to also make gasoline-power cars.

Trucks aside, America could wind up with no tailpipe emissions whatever: The nation's car fleet would be 100 percent electric, and gasoline stations would become battery stations.

But if we depend on electric cords, electric cars will play only a minor role in our automotive and environmental future.