Doesnt look like there was a driver.
Those tractor tires are about 5 feet tall, and its moving at a good pace that you probably could match in a run - however boarding the tractor would require you to run in the little space just ahead of the main tire, hopping up on to the step, climbing into the cab, and heroically commandeering the tractor and bringing it to a stop.
sounds super easy until you are running in front of that 5 foot tire, while concentrating on grabbing hold of a hand hold and placing a foot on a the step to lift yourself into the cab.
its hard enough for some folks to climb aboard when the tractor is stopped.
and one false move... guess where you would end up?
under that big tire, attached to that heavy tractor.
Looks like it was running a big circle anyhow. the thing to do would have been to let it run out of fuel, or find a willing big rig truck driver to wedge it between the building and his truck cab buying someone time to board it while it was stuck.
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