Remember humans, car safety is important for all our fur friends!
Personally, I am very impressed with @ruffwear.
Their gear is very high quality, reliable, and it fits well. They have a specific car harness that is amazing, however personally I use their normal harness. This plus a seat belt adapter, seems to be the safest way, while keeping me comfortable for all my car rides!
However any car seat, crate, or any other device is perfectly fine, as long as we are safe! Don't forget to buckle us up! (this isn't sponsored or anything, I just really enjoy their products!)