Yes, Best option is Create good Public transport service like singapore. Otherwise It will be a Huge problem in the future.Land not expanding , but vehicles getting increase day by day.
before doing all that u have suggested first we should give the people a proper alternative. otherwise ........ bus. something like mono rail which is coming up also is a good alternative.
Better public transportation is a must nodout although its a far fetched dream for SL.
MRT for colombo Thats not in our lifetime Monorail maybe. Only solution is AC buses but they tried it and failed as i recall.
Well its Sri Lanka guys that means were focked.