A Fix for the Metro System

In reading about the recent Metro accident on the Red Line ["At Least 6 Killed in Red Line Crash," front page, June 23], I have seen no mention of a basic weakness of the system's design: Humans should not be backing up computers.

Computers are highly reliable, operating year after year without error. This can lull operators into a false sense of security. Then, when a computer malfunctions, there's a good chance the operator will react slowly or not even notice the error.

This has been a factor in accidents on the Bay Area Rapid Transit system in San Francisco, in the Exxon Valdez oil spill and in dozens of other system failures. A better approach is to have humans operate the trains with the automated system as a backup to catch human error.

CRAIG MILLER

Alexandria