Best option for seeing cars from behind

Garmin varia radar if you have the funds or a cheap mirror works also.

Do you really want to see the car that is about to hit you? Pick your roads wisely and have faith you'll make it back home.

I had the same concerns when I first started out and have tried various mirrors with the helmet mounted one probably being the best. It's a relatively inexpensive way to go if you want to see behind you. I'm intrigued by the Varia but can't justify the money.

After I became more comfortable on the road I found that I wasn't really using the mirrors and they were more of a pain. Overtime I've become pretty aware of my surroundings and have found some relatively safe routes to ride. I should also mention that I think my tolerance for close calls is much greater than some of my friends who don't ride as much. I remember being passed by a car late last year and my buddies freaked out at how close the person had gotten to us... but it didn't even register as a close call to me.

I love my helmet mounted mirror. Where I ride, plenty of roads do not have a paved shoulder, and plenty of motorists have no inclination whatsoever to give me any room when passing, so I really value being able to keep an eye on vehicles coming up behind me. If I had paved shoulder and/or courteous motorists I might not need it, but I consider it an absolutely essential piece of gear.