100% in agreement with cberry20b.
Probably the most direct and concise post on this topic and before anybody starts going on about it being off-topic it is most certainly ON Topic.

If a Public Transport system does not appear or feel safe to the majority of those using it then it will rapidly decline and die.

The reasons for the current decrepitude in Dublin City Centre lie in a total unwillingness of the Citys Administration to get involved in ACTIVE policing at the lowest level.
This means disrupting,annoying and repeatedly targetting the supposedly low-level criminals until their human rights buds are raw.
Stop+Search,hassle and photograph (the latter is REALLY unpopular with the streetwise criminal fraternity) at every opportunity.

High Profile pro-active policing with the clear message that the rules are NOW being enforced on the streets and on Public Transport will quite rapidly bring about improvements....However,since this will involve expense I cannot see senior Civil Servants who reside in Howth or Killiney being disposed towards funding it.

It was not by accident that New York`s battle against it`s almost terminal reputation for crime and violence began on its Subway and Bus services and neither should the success of that battle be lost on us either.