Learn Hardcore Croatian: Ako voziš kroz crveno, policija može dati veliku kaznu, jer ne poštuješ pravilo. - If you ride through a red light, the police can give a big fine because you are not respecting the rule.

Ako means “if” and introduces a condition – something that may or may not happen.
- Ako voziš kroz crveno… = If you drive through a red light… (maybe you will, maybe you won’t).
Kad basically means “when/whenever”, and often implies something that happens regularly or certainly:
- Kad voziš kroz crveno, policija ti uvijek da kaznu.
  = When(ever) you drive through a red light, the police always give you a fine.

You can hear Kad voziš kroz crveno in some contexts, but:

Ako is the more neutral and typical choice in a warning like this.
Kad would feel more like you do this as a habit or like a general law: “whenever you drive through a red, X happens.”

So here Ako is the best translation of English “if” in a conditional sentence.

Why is the verb voziš (present tense) used, when the English sentence is talking about a possible future event?

In Croatian, the present tense is very often used in real conditional sentences with ako:

Ako voziš kroz crveno, policija može dati veliku kaznu.
Literally: If you drive through a red, the police can give a big fine.

Even though it’s grammatically “present,” it covers:

General truths / typical consequences.
Future possibilities, just like English “If you drive…” (which is also grammatically present but future in meaning).

You normally do not say:

✗ Ako ćeš voziti kroz crveno… – this sounds wrong or at least clumsy.

So: present + present is the standard pattern for this kind of conditional in Croatian:

Ako radiš to, dogodi se ono.
If you do this, that happens.

Why is it voziš and not voziš se? What is the difference?

Both come from voziti “to drive / to ride”, but there’s a nuance:

voziti (nekoga/nešto) – to drive (someone/something), to operate a vehicle
- Voziš kroz crveno. – You are driving (the car) through a red light.
voziti se – to ride / to be driven, often implying you’re just a passenger, or emphasizing being transported.
- Vozim se autobusom. – I’m riding the bus.
- Vozim se autom. – I’m riding in a car (not necessarily driving).

In this context, the important thing is the act of driving the car and breaking the rule, so voziš (without se) is the natural form.

If you said:

Ako se voziš kroz crveno…, it would sound like you’re just being driven through a red light, not necessarily the driver. That’s possible, but it changes the focus.

What exactly does kroz crveno mean? What is missing here?

kroz crveno literally means “through (the) red”, and it is shorthand for:

kroz crveno svjetlo – through the red light
or
kroz crveno na semaforu – through the red (light) at the traffic lights

Native speakers often drop the noun (like svjetlo “light”) when it’s obvious from context. Then only the adjective crveno remains, acting like a noun. That’s why the phrase is just:

voziš kroz crveno = you drive through a red (light)

So the full, explicit version would be:

Ako voziš kroz crveno svjetlo… – completely correct but longer and less idiomatic in everyday speech.

Why is it kroz crveno and not kroz crvena or something else? Which case is this?

The preposition kroz (“through”) in Croatian always takes the accusative case.

The understood noun is svjetlo (light), which is:

Gender: neuter
Singular nominative: svjetlo
Singular accusative: svjetlo (same form, but still accusative)
Adjective: crven (base form)

In accusative singular neuter, the adjective is crveno, matching svjetlo:

kroz crveno (svjetlo) – “through the red light” (accusative)

So:

crveno here is neuter accusative singular, agreeing with the hidden noun svjetlo.
kroz crvena would be wrong in this meaning.

Why is it policija može dati veliku kaznu and not something like policija može da da veliku kaznu?

Croatian does not use da after moći (“can, may”) the way some other languages use a “that”-word.

The normal pattern is:

moći + infinitive

So:

policija može dati kaznu – the police can give a fine

You should not say:

✗ može da da kaznu – this is ungrammatical / very unnatural.

Compare:

Želim da dođeš. – I want you to come. (here da + present is correct)
Moram doći. – I must come. (morati + infinitive)
Mogu doći. – I can come. (moći + infinitive)

So the sentence uses the standard moći + infinitive structure: može dati.

What does veliku kaznu show about cases and agreement? Why veliku and kaznu?

kazna means “penalty, fine, punishment”.

Its forms (singular):

Nominative: kazna – subject (Kazna je velika.)
Accusative: kaznu – direct object (Dobivam kaznu.)

In the sentence, kaznu is the direct object of dati (“to give”), so it must be in the accusative.

velik is the adjective “big”.

Feminine accusative singular: veliku

So:

veliku kaznu = adjective (veliku) + noun (kaznu)
Both are feminine accusative singular, matching in:
- gender (feminine)
- number (singular)
- case (accusative)

This is standard adjective–noun agreement in Croatian.

What exactly does kazna mean here? Is it always “punishment”?

kazna generally means “punishment”, but in legal / traffic contexts it very often specifically means a fine (a monetary penalty).

So in this sentence:

veliku kaznu is best understood as “a big fine” (a lot of money).

Other uses:

dobiti kaznu – to get a punishment / detention / fine (context-dependent)
novčana kazna – financial penalty, monetary fine
zatvorska kazna – prison sentence

Here, because it’s about driving through a red light, the natural English translation would be “a big fine”, not just “a big punishment”.

Why is jer used here? What’s the difference between jer and zato što?

jer means “because” and introduces a reason clause.

In many sentences, jer and zato što are very close, but there is a nuance:

jer:
- Simple “because”
- Often more neutral, used in explanations.
- Usually follows the main clause:
  Kasni, jer je bio u gužvi. – He’s late because he was in traffic.
zato što:
- Literally “for that reason that…”
- Often slightly more emphatic, highlighting the cause.
- Can combine with zato in the main clause:
  Kasni, zato što je bio u gužvi.
  or
  Zato kasni što je bio u gužvi.

In Jer ne poštuješ pravilo, the speaker is just giving the reason in a straightforward way:

policija može dati veliku kaznu, jer ne poštuješ pravilo
= the police can give a big fine, because you are not obeying the rule.

You could also say:

… zato što ne poštuješ pravilo. – also correct, with a bit more emphasis on the cause.

What does ne poštuješ mean exactly, and how is it formed?

poštovati means:

to respect (a person)
to respect / observe / obey (a rule, law, agreement)

Its present tense (singular):

ja poštujem – I respect
ti poštuješ – you respect
on/ona/ono poštuje – he/she/it respects

To make it negative, Croatian simply adds ne in front of the finite verb:

ne poštujem – I don’t respect
ne poštuješ – you don’t respect
ne poštuje – he/she/it doesn’t respect

So ne poštuješ = “you don’t respect / you don’t obey”.

In this sentence:

ne poštuješ pravilo = you are not obeying the rule / you don’t respect the rule.
There is no extra auxiliary like English “do” (Croatian just uses ne + verb).

Why is it pravilo (singular) and not pravila (plural)? Could we say ne poštuješ pravila?

pravilo = rule (singular)
pravila = rules (plural nominative / accusative)

In this sentence:

pravilo is accusative singular (same form as nominative for neuter nouns), object of poštovati:
- ne poštuješ pravilo – you don’t obey the rule (the specific traffic rule about stopping at red).

If you said:

ne poštuješ pravila – you don’t obey rules (in general, or several rules).

Both are grammatically correct, but the meaning changes:

pravilo (singular) focuses on this one specific rule (the red light rule).
pravila (plural) would sound like you are someone who generally doesn’t follow rules.

Why is there a comma before jer in Croatian? Is that required?

Yes, in standard Croatian a comma is normally required before “jer” when it introduces a clause:

Policija može dati veliku kaznu, jer ne poštuješ pravilo.

This is different from English, where you might or might not put a comma before “because” depending on style and ambiguity.

In Croatian:

Subordinate clauses introduced by jer, zato što, iako, ako, kad, etc. are typically separated by a comma from the main clause.
So you also get:
- Ako voziš kroz crveno, policija može dati veliku kaznu.
- Kaznio me je, iako sam vozio polako.

So the commas in the sentence:

after Ako voziš kroz crveno
before jer

are both standard and expected in written Croatian.

Is voziš informal “you”? How would I say this more formally or politely?

Yes. voziš is 2nd person singular, used for:

talking to one person informally (friends, relatives, informal situations).

To be more polite or formal (speaking to a stranger, an older person, in official communication), you use 2nd person plural:

Ako vozite kroz crveno, policija može dati veliku kaznu, jer ne poštujete pravilo.

Changes:

voziš → vozite
ne poštuješ → ne poštujete

This is the so‑called V–form (plural “you”) used for polite address in Croatian, just like vous in French or Sie in German.

Could I say Ako bi vozio kroz crveno…? How does the conditional work here?

You can form a conditional with bih/bi (the conditional auxiliary), but it’s used differently, and in this kind of sentence it often sounds awkward or unnecessary.

Normal, natural version:

Ako voziš kroz crveno, policija može dati veliku kaznu.
(present + present: real condition)

A conditional version might be:

Ako bi vozio kroz crveno, policija bi ti mogla dati veliku kaznu.

However:

This sounds more hypothetical and is stylistically heavier.
You need to adjust the rest of the sentence to match the conditional mood (bi mogla dati, “could give”).

In everyday speech, for a straightforward rule or warning, Croatians strongly prefer:

present with ako, not conditional with ako.

So for your original sentence, Ako voziš… is the most natural and recommended form.