New threat for public transport users ?

We’re (almost) all shocked by what happened lately onboard Germanwings plane over French Alps. Shortly after it turned out that this awful accident wasn’t caused by a fault of machine or by human error, but was wittingly scheduled by second pilot, Lufthansa ordered a rule of two pilots in cockpit. Maybe it will help to increase safety level in planes, but I thought what about e.g. buses. Even local city busdriver can kill his passengers falling from bridge, driving into river etc, Alps are not necessary and it’s not possible to place two drivers behind steering wheel. And just today I heard on tv that a young woman wanted to commit suicide  turning abruptly sterring wheel of a bus full of people between Warsaw and Lublin in Poland. Fortunately driver managed to pulled away and stop avoiding crash but it was really close. But what if a driver was woman and a suicider strong man? Everyone presumes that young woman was influenced by last news about Germanwings plane. What makes people act that way that they want to take with them to grave as many other people as possible? Do they want to become “celebrities” of some crazy kind? Should we be afraid of using public transport more than so far?