This is a bit of a fav topic of mine, firstly was never about increase in rail traffic, no changes to track, signalling, rollingstock or staff....just a political comment which was never addressed. Traffic is no better in total (I live in Chadstone area) but it has reduced stress levels that you may get stuck at a level xing for 10 minutes just when you are running late.
It was never going to improve traffic as "Traffic" equals the excess of demand for roads against the supply of roads....and the levels crossing neither increased supply or reduced demand. It only flattened everything out, by that I mean in the past when I was stuck at a xing it invariably meant traffic on the other side was very light and I caught up some of the minutes lost, a car entering the traffic on the other side gained minutes also so the net result fairly benign.
An example I can give is my daily commute to Northcote which progresses along Malvern rd and I can choose to cross the Glen Waverley line at either Burke Rd (new level crossing removal project) or Tooroonga Road (existing level crossing). I often am better off taking the level xing at Tooroonga as Burke road is just clogged 200m beyond the now vanished crossing. $200m to remove the crossing only induced everyone to use Burke with little change, the big winner of the Burke removal is CityLink with the lights noticeably favoring the entry and exit ramps.
The big mindset change that needs to happen is the introduction of clearways....everywhere on main roads