what is the relation about the Boltzmann distribution and candidate trajectories?

[siami233]

Thanks for your good job! In your paper you mentioned,"we assume the distribution is a Boltzmann distribution related to the returns of trajectories." why you use Boltzmann distribution describe the probity of trajectories.
In the fig1, When you are evaluating trajectories, I noticed that the horizontal axis of the probability distribution graph on the right contains "lane change left, lane keeping, lane right". What does this mean? Why does "lane keeping" correspond to the highest probability on the vertical axis?