Look at a 2017 Prius Two, which has standard active safety features such as automatic braking and lane departure alert. It of course gets great gas mileage. I have a 2016 Prius Four and it's awesome. I also own a 2005 Prius I bought new which now has 250,000 miles. They are very reliable.
A Mazda 3 is also a fun and fuel-efficient car. Not as many standard features as the Prius though.