Are trams effective in getting car commuters onto them, when they would not do so if it was bus or train?

Are trams effective in getting car commuters onto them, when they would not do so if it was bus or train?

Are there more cost-effective ways which are better at reducing greenhouse gas emissions?

Where is the evidence that building tram networks on roads and railway lines gets car commuters to use public transport, rather than bus/train users switching to the new, swanky tramway?