Originally Posted by
no1mad
Could be the reason why "others are zooming past" you is because they are simply stronger riders.
This. Just food for thought: I routinely pass roadies on my fully-loaded Trek Allant (~50 pounds). Strong legs beat lighter bikes on everything except going up hills. I don't remember seeing any hills in Chicago last time I was there.
You will get faster startups with a road bike though. Are the other riders passing you mid-block, or are they beating you at the red lights?