Coming back from B.C. one night, the low fuel indicator light came on at Field B.C. I zeroed the trip out of curiosity, and we got all the way to just past Cochrane AB, before it sputtered to a crawl. The odometer was at 180 kms (112 miles). It was still able to move on electric power, but at a reduced speed. I opted not to push it to the very limit, so I put in the gasoline I had on board, and made it to the next gas station. I have run it completely to a stop unintentionally after running out of fuel. It was a bad situation, because I couldn't even raise the windows. I didn't want to leave it by the roadside with the windows down, so I had to rely on a stranger to bring me gasoline. Don't ask me how far I got on electric power alone, but it was a lot less than I expected.
It's never good to run out of fuel, in any car.... When the light starts flashing, you SHOULD get gas. Note how much fuel you put in, probably around 9.5. And you know if for some reason you HAD to drive, you have about 2 gallons to do it on. Which should be enough to get to any fuel station... The fuel also cools the fuel pump. When it gets too low, it's not being cooled as well.
There are other threads about intentionally testing range to fuel starvation for Gen3 liftback and 2017-ish Prime. Is your 'testing' (deliberate and/or unintentional) about either of these models, or is it about your 2024 Prime? If for either era Prime, this belongs in a different forum here on PriusChat, not in this Gen3 non-plug-in forum. Depends on where one is going. Eastbound from Field, he has only 16 miles to get to Lake Louise. Sounds like he got past Banff and Canmore too, almost to Calgary. Westbound, about 35 miles to Golden. But the next section, 90+ miles from Golden to Revelstoke, might require more than 2 gallons during winter weather. South of the border, we have several places without fuel service even longer than that, so one might need to turn around and backtrack. One section I have pictured in other threads, will need 3 gallons one-way in good weather, more in lousy winter weather. It is cooled by fuel flowing through inside the pump, not from a bath outside. Cooling ceases at about the same point as fuel starvation.