I sort of recall something about things failing "green", but no details.

>Also, in those days, BART did not use wayside signals at all on the main track, relying instead solely upon automated controls with no cab signals either. --snip--

The wayside signals are largely the result of the influence of the late Frank Harshbarger, who worked for GRS before coming to BARTD.

>The word "Failsafe" symbolizes one of those problematic concepts that cannot be understood without a well structured frame of reference. If you ask most aerospace engineers what it means, they will deny it exists. They rely solely on calculated probabilities instead. If you ask most industrial control engineers, they accept merely "robust design" to be sufficient. The concept of "Failsafe" is accepted fully, only by railroad signal and train control engineers. And since nothing man does can ever become absolute, it could be considered a bit of a stretch even there.

"Fail safe" in railroading has always meant "stop all movement". Robinson redesigned his track circuit to be a closed loop for this very reason. BARTD is a railroad, not an airline; to compare the two is disingenuous. Fortunately the law which created BARTD also put it under the oversight of the State PUC, otherwise there would have been no oversight at all.