Zbog magle nismo odmah vidjeli izlaz za kružni tok.

Because zbog always takes the genitive case in Croatian.

• basic form: magla = fog
• genitive singular: magle

So:

• zbog magle = because of the fog

This is a very common pattern:

• zbog kiše = because of the rain
• zbog prometa = because of the traffic
• zbog posla = because of work

It is understood, not stated.

Croatian often leaves out subject pronouns when the verb already shows who is doing the action. In nismo vidjeli, the form nismo already tells you the subject is we.

So:

• (mi) nismo vidjeli = we did not see

Adding mi is possible, but usually only for emphasis or contrast:

• Mi nismo vidjeli izlaz, oni jesu.
  We didn’t see the exit, but they did.

Because Croatian past tense is normally formed with:

• a present-tense form of biti (to be)
• plus the past participle

Here:

• nismo = we are not / we did not (the negated auxiliary form used in the past tense)
• vidjeli = seen

Together:

• nismo vidjeli = we did not see

This is the normal Croatian way to build the past tense:

• smo vidjeli = we saw
• nismo vidjeli = we didn’t see

The past participle must agree with the subject in gender and number.

Here the subject is an understood we.

• vidjeli = masculine plural (also the default plural for a mixed group)
• vidjele = feminine plural

So:

• nismo vidjeli = we didn’t see
  used for a group of men, or a mixed group, or when gender is not being specified
• nismo vidjele = we didn’t see
  used if the speakers are all female

This is something English does not do, so it often feels unusual at first.

A learner often expects one verb to cover both see and look/watch, but Croatian usually separates them.

• vidjeti = to see, to notice, to catch sight of
• gledati = to look at, to watch

In this sentence, the idea is we didn’t see / notice the exit, so vidjeti is the right verb.

Compare:

• Nismo vidjeli izlaz. = We didn’t see the exit.
• Gledali smo u znak. = We were looking at the sign.
• Gledamo film. = We are watching a film.

Izlaz is the direct object of vidjeti, so it is in the accusative case.

However, izlaz is a masculine inanimate noun, and for many masculine inanimate nouns, the accusative singular is the same as the nominative singular.

So:

• nominative: izlaz
• accusative: izlaz

That is why the form does not visibly change.

Compare with another masculine inanimate noun:

• znak = sign
• vidim znak = I see a sign

But with animate masculine nouns, the accusative often changes:

• student = student
• vidim studenta = I see the student

Here za means something like for or toward, and this is a very natural road/traffic expression.

• izlaz za kružni tok = exit for the roundabout / exit toward the roundabout

On road signs and in traffic language, Croatian often uses:

• izlaz za + destination/place

Examples:

• izlaz za centar = exit for the city centre
• izlaz za Zagreb = exit for Zagreb
• izlaz za aerodrom = exit for the airport

So this is not a random choice of preposition; it is a common fixed pattern in this kind of context.

After za in this meaning, Croatian uses the accusative.

So kružni tok is accusative here. But again, because it is masculine inanimate singular, the accusative looks the same as the nominative.

• nominative: kružni tok
• accusative: kružni tok

That is why you do not see a change in the ending.

Odmah means immediately, right away, or at once.

In this sentence:

• nismo odmah vidjeli = we didn’t see right away / we didn’t immediately notice

Its position is natural, but Croatian word order is fairly flexible. You could move odmah in some contexts, though the emphasis may shift slightly.

For example:

• Zbog magle nismo odmah vidjeli izlaz...
  neutral, natural
• Zbog magle odmah nismo vidjeli izlaz...
  less natural in most contexts
• Nismo odmah vidjeli izlaz zbog magle.
  also possible, but the focus changes a bit

So the sentence places odmah where it most naturally modifies vidjeli.

Yes, Croatian word order is more flexible than English, but different orders can sound more or less natural depending on what you want to emphasize.

The given sentence is very natural:

• Zbog magle nismo odmah vidjeli izlaz za kružni tok.

Possible alternatives include:

• Nismo zbog magle odmah vidjeli izlaz za kružni tok.
• Izlaz za kružni tok zbog magle nismo odmah vidjeli.

These are grammatically possible, but they change the rhythm or emphasis.

A good general rule is:

• fronting Zbog magle emphasizes the cause first
• keeping nismo odmah vidjeli together sounds smooth and natural
• moving izlaz za kružni tok forward can sound more emphatic or marked

So yes, word order can change, but the original version is probably the most neutral.

Yes. Kružni tok is the standard everyday term for a traffic roundabout.

Literally, it is something like circular flow/traffic flow, but in normal usage it simply means roundabout.

You may also hear it in phrases like:

• na kružnom toku = at the roundabout
• ući u kružni tok = to enter the roundabout
• izaći iz kružnog toka = to exit the roundabout

So this is a very useful traffic expression to learn as a whole.

Only the past participle would change:

• Zbog magle nismo odmah vidjele izlaz za kružni tok.

The difference is:

• vidjeli = masculine plural / mixed group default
• vidjele = feminine plural

Everything else stays the same.

This is a very common agreement feature in Croatian past tense.