What kind of car do you have? Have you considering taking one or both wheels off and putting the bike inside the car?
As for whether the Saris is secure. It is if you strap it on correctly. When I use mine, I get the rack pretty well situated, then I put the bike on it and then I retighten every strap. I recheck it here and there along the way. What's disconcerting is that as you drive at highway speed, you will see the bike swaying a bit. I've yet to have an incident yet.
That said, I usually just put my bike in the car. I have a 4-door sedan but it's rear seats don't go down for some reason (a detail my dealer didn't point out to me). With just my front wheel off, I can put the bike behind my front seats. It sits upright, with the handlebard turned toward the side if you can picture that. I use a velcro strap to hold it in place behind my seat. My husband can put his bike in my trunk but he has to take both wheels off.
He also has a 4-door sedan, but its seats go down. We can put both bikes in the car if we take the front wheels off and still have room for a week's worth of luggage and gear.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher