Prius 2019 L Eco - EV mode is deactivated.

I imagine that the EV percentage will be radically affected by terrain and traffic. Flat roads at interstate speeds will probably give the lowest percentage of EV.

 

EV Mode on my 2019 LE only works at speeds less than 15mph. I have not read the BOOK so I don't know if there are other things to know about the mode but yeah, it turns it off immediately if you're moving at regular driving speeds. It tells you on the display why it's shutting off.

 

Don't worry about EV Mode - it'll come on when and if it's ready - it also comes on when idle, or sometimes going down hill, and during regenerative braking. Some people try to force it - and sometimes that's beneficial, but as often than not, can work against economy.

Worth reading the Manual though. It's only 828 pages. You can download it too - and can then search it.