You are correct. And it's not just the images either, it's to illustrate the point that difficulty merging lowers the average flow-rate below that of "maximum lane occupancy".
I have to correct myself: Yes you're correct. I thought that the top left blinking arrow indicated that a car passed but that's very wrong. It's just displaying the road construction arrow and the rate or cars is indeed about twice as high.
There are considerably more cars on the Left GIF though. I guess if the number of cars in both lanes and in both GIFs was equal, the average speed of cars in the right GIF would be lower such that flow (throughput) would be the same.
Cars per second are the same. Open the two gifs next to each other. Each has 8 frames and the top right lamp is on for 4 and off for 4.
Is it my browser, or is this completely wrong? For me, the right side moves about double the amount of cars into the upper edge of the image. And I believe that this is the point of the section — it wouldn’t make any sense otherwise.