Lane change behavior looks completely unrealistic to me. I see cars switching lanes on deceleration into a traffic jam, which doesn't buy you anything (both lanes are stopped) and is extremely dangerous (you're cutting off cars approaching fast from behind and braking at the last minute). Never seen this happen in real life, except maybe at toll booths.

On the other hand, there is no lane switching when traffic on adjacent lanes clears up. In real life, drivers will quickly switch if a nearby lane starts moving. They can't see whether their own lane is also clearing up ahead, and most people won't take any chances.