Ours stays on pretty much always. Too lazy to take it off and comes in handy in weird situations. I was storing extra covid TP in it for a while

My husband always checks gas mileage, and he said the car top carrier causes a 15-20% reduction in gas mileage on our SUV.

I wouldn't leave it on because I wouldn't want to worry constantly about hitting low-hanging objects/parking garages/trees/overhangs.

Anonymous wrote:The answer also depends on how you drive. If you rarely get on the freeway, then the impact on mileage should be small, since wind resistance won't be a major factor. If you spend a lot of time on the highway, then it will absolutely have a more noticeable effect.

Many parts of the country are far from freeways, but the main roads are referred to as highways and have speed limits of 55. Aerodynamics definitely matter on these types of roads.

The answer also depends on how you drive. If you rarely get on the freeway, then the impact on mileage should be small, since wind resistance won't be a major factor. If you spend a lot of time on the highway, then it will absolutely have a more noticeable effect.

We have a Prius and use a clamshell-type rooftop carrier for family trips. I would say that our average mileage goes from ~45 to ~35 when it's on. But since it lets us get by without buying a bigger car, it's a good solution for us.

If we travel to visit family, spend a week or two with them, and then return, we just leave the rooftop carrier on while there, since we're not driving much, but we definitely take it off between long trips.

One other thing to watch out for -- if you are attaching it with straps as opposed to getting something installed on the roof, the straps can leave marks on the roof.

Anonymous wrote:Don’t do that. When they are empty not so safe.

Why?

Don’t do that. When they are empty not so safe.