There’s an road with an intersection exactly like this that I commute to work on everyday, with the only difference being that it has a 35 mph limit.

Upon reflection though, when I have been in the leftmost car’s position, I have never ever turned left onto the three lane road. Still though, this road is not usually busy and you can easily see over the road division.

I have seen people floor it just barely in front of me when they turn to the left though, but that’s just because they’re impatient, not because someone waved them on.