As I said below, one reason they might run a transmission is so that they constantly run the engine in the most energy efficient zone (which might vary by up to

As I said below, one reason they might run a transmission is so that they constantly run the engine in the most energy efficient zone (which might vary by up to 30%), giving them a longer battery life. There are other factors to consider about whether this is justified, however, like the losses introduced in the transmission. Whether the drivers are trained to take advantage of this is another story.