Only one solution is Metro Bus service.
See Malaysia, Singapore, Sweden, Australia.
Bus owners withdraw their buses from 174 route day by day.
Ex: if 1 bus stops its route then,
125 passengers want to have alternative ways. By personal car, threewheels, bike, etc. Then additional 125 vehicles coming to the road instead of one bus.
Restore better Colombo Metro bus service and attract to their persons using unwanted personal vehicle journeys.
Mono railway or Tramp cars are long-term things
Pass these ideas to city traffic planner