Regarding the District's mall evacuation experiment ["Tepid Applause for July 4th Test," Metro, July 6]:

The only way crowds in urban areas can be evacuated efficiently is by prioritizing transit that doesn't involve cars.

During evacuations, when moving large numbers of people quickly and efficiently is urgent, providing motorists with continuous green lights for three minutes per cycle at the expense of pedestrians is the wrong strategy. The message is that if you have a car and it's parked near where you are, you'll be helped to speed out of town. Those on foot will have to wait.

An emergency situation could involve closing some Metro stations, forcing those not driving to walk for many blocks. If people believe that their lives depend on getting out of town quickly, they will be unlikely to accept delay and won't abide by the "don't walk" signs. If cars are given priority, motorists will be encouraged to speed and pedestrians to jaywalk, with inevitably lethal consequences.

A better approach would be to focus on moving people instead of cars by restricting, rather than encouraging, the use of automobiles.

During emergencies, people should be barred from moving parked cars, whether in garages or on the street. Instead, special limited-stop Metrobus evacuation services could carry thousands of people along designated emergency bus-only corri- dors to safe areas. Physically fit private citizens could be encouraged to use bikes. Taxis also could be required to fill all seats before heading out of town.

Moving more people in fewer vehicles would mean a safer and more efficient evacuation. Deadly chaos is the alternative.

ALLEN GREENBERG

Washington