My experience running out of gas on the highway (CT 200h)

Hello folks,

While I've tested running out of gas once in my 2012 Prius C that I had before, I never really planned to do the same with my 2014 CT. But it happened anyway.

After miscalculating my true range, I ran out of gas on the highway one night, driving 60 MPH. Here's what happened:

The car immediately shut the engine off. EV light came on and the car began to slow down. Throttle inputs were completely ignored. I knew that I was coming up on an exit that led to a gas station I go to often (lucky me), so I cruised into the exit lane and headed off the highway.

At this point the car was reaching 40 MPH, which is just about the max speed for EV mode. I checked the hybrid battery level, and it was around 70% or so, so I let the car slow down to about 20 MPH and then started to hold the speed (in an attempt to extend the range of the battery). At this point throttle inputs were working, but it worked just as it would in EV mode, except it wouldn't kick the engine back on if I tried to floor the pedal (did it as a test).

I was able to drive very slowly until I reached the gas station and pulled in. Luckily, this happened around 2am so all the lights were green and I never stopped, even when turning at a light. Didn't want to risk not being able to drive away after a stop.

Once at the pump, I turned the car off, filled up, and the car started up just fine afterwards, and everything worked normally again.

The same was true for my Prius C. It always started up and drove fine after refuelling. (It ran out once when my mom was driving it. She reported the car just kept slowing down so she was able to reach the shoulder just fine.)

 

From my fuelly report (3/22/16), I had driven 571 miles since my last fill up. Car read 51.7 MPG but true MPG was 48.8. (Difference of 2.9. I normally calculate based on 3 difference, but I think this time I did 2 by accident.)

DTE was null, as the range always drops to 0 long before I'm out of gas. At 48.8 true MPG, range for 11.9 gallons is 580.7 miles.

I never calculate miles past low gas warning because I know it tends to be 150-200 miles from true empty, and fluctuates based on MPG, so I have no idea.

I kept driving because my entire trip per day is something like 550 miles on average, and I can usually make it to the gas station the next day 2 miles from home. Just easier to gas up once per day than twice with my limited schedule. This should cover your final two questions.

Also, a rough calculation from Google Maps shows I drove around 1.5 miles to the gas station from when the engine shut off.

My guess is that the car will stop you before you completely empty your tank. I filled up 11.702 gallons, which is really odd because I once made it to a gas station and filled up 11.813 gallons (fuelly report for 2/9/16 for reference).

 

I maintain a pretty good fuelly log for my car, and while fuelly shows the true MPG for each fill up, I always post the car's MPG number (which I reset at each fill up). Looking at hundreds of these numbers, the difference is usually around 3 MPG when you're around the 50 MPG level. It's closer to 2 when you're around the 40 MPG level. So you can use this to subtract 2 or 3 MPG from what your car reads, and multiply it by 11.9 (or less to give yourself a margin of error) and figure out your true DTE.

 

It's probably because my MPG is usually very consistent.