It is a desperate time of year in Yellowstone. There are tens of thousands of visitors, many from Asia and Europe, plus a fair number of Americans. None of them have apparently ever seen a live wild animal, so when there is the smallest chance of seeing a bison or an elk or even possibly a bear, everyone pulls over and gets out their cameras and binoculars. The people that don't have space to pull over, just stop in the middle of the road.
If you look carefully at these photos, you will notice that only one side the road has a shoulder. On the other side, there is a 6-10" drop off to a ditch which is intended for draining. In many places in the park, you can see the scrape marks made by the undersides of vehicles as their wheels drop off the pavement.
Do you see the angle the red truck is parked at on the left? I don't know how he got out of his car.
Here are some photos of the mud pots. Some are pretty thick like pea soup and others are more watery.
This is a hillside that started steaming after an earthquake about 20 years ago. It eventually stopped steaming, but all the trees died from the heat.
And some more steaming and boiling pots.