I drive the car least/the least in our family.

[Vladv1]

Which is correct? I drive the car least in our familty/ the least in our family.

 

[Rover_KE]

In what context are you asking this question? Where did you find it?

 

[Vladv1]

In what context are you asking this question? Where did you find it?

I want to say using this sentence tham I use the car much less frequently compared to all in my family

 

[emsr2d2]

I want to say using this sentence tham that I use the car much less frequently compared to all than other people in my family.

That's not the same as your original sentences. If you say you use it "the least", you could still drive it very frequently but other people use it more.

 

[emsr2d2]

Which is correct?

1. I drive the car least in our familty family.
2. I drive the car the least in our family.

Note above how you should have laid out post #1. Every time you give us more than one option, present them as a numbered list.
The version with a slash is possible, as you can see from how I improved your title, but actual posts should be laid out much more clearly.