Word order by the negative of 'might + Perfect Infinitive'

[Sls]

Hi!

I did an entry level test at school today and it came up for disscusion which of the following is correct:

They don't know why the car crashed. The driver might not have seen the red light.
- OR -
They don't know why the car crashed. The driver might have not seen the red light.

Intuition tells me the word order in the second option is right, but grammar rules seem to contradict my opinion. Maybe both are equally correct?

[Yankee]

Hi sls
.
You intuition is leading you in the wrong direction.
.
Generally speaking you would have this word order:

modal verb + not + have + past participle

- might not have done
- may not have done
- cannot have done (can't have done)
- could not have done (couldn't have done)
- will not have done (won't have done)
- would not have done (wouldn't have done)
- should not have done (shouldn't have done)
- ought not to have done
- must not have done

You might possibly hear the word not after the word have from time to time, but that wouldn't be the "normal" word order (and would probably only be done for some special reason -- such as extra emphasis on the word not).

By the way, in spoken English you'll usually hear a double contraction with many of the above forms:

would not have done --> wouldn't've done

Amy

[Sls]

Thanks, Amy!
I won't rely solely on intuition anymore