Usput proveravam red vožnje da ne propustim polazak.

Usput means something like along the way, in the meantime, or while I’m at it.

In this sentence, it tells you that checking the timetable is something the speaker does as an extra action, not the main event.

A few useful points:

• usput is an adverb
• it is very commonly placed near the beginning of the sentence
• it often gives the sense of incidentally or while doing something else

Examples:

• Usput kupujem hleb. — I pick up bread on the way / while I’m out.
• Usput ću ga pozvati. — I’ll call him while I’m at it.

Proveravam is the imperfective present form of proveravati / proveravati-proveriti type pairing, and here it describes an action as a process or habitual/ongoing action: I’m checking or I check.

Why not proverim?

• proveravam focuses on the activity itself
• proverim is perfective and usually points to a completed single result: I check / I will check and finish checking

In a sentence like this, proveravam sounds natural because the speaker is describing what they are doing in general or at that moment.

Compare:

• Usput proveravam red vožnje... — I’m checking the timetable...
• Usput proverim red vožnje... — more like I check the timetable (once, completely); this can work in some contexts, but it gives a more completed, one-off feel

Red vožnje means timetable, schedule, especially for buses, trains, and similar transport.

Literally, it is something like order of driving/running, but you should learn it as a fixed expression meaning transport schedule.

Very common examples:

• autobuski red vožnje — bus timetable
• red letenja — flight schedule
• red plovidbe — sailing schedule

So in normal usage, red vožnje is the standard expression for a public transport timetable.

Because vožnje is in the genitive singular.

The phrase is:

• red — order / schedule
• vožnje — of travel / of running / of transport movement

So structurally it is:

• red vožnje = schedule of transport operation, which in natural English becomes timetable

This kind of noun + genitive structure is very common in Serbian:

• čaša vode — glass of water
• karta grada — map of the city
• plan putovanja — travel plan

Here:

• nominative: vožnja
• genitive singular: vožnje

This is a very common Serbian structure for expressing purpose: so that... not, in order not to...

So:

• da introduces the purpose clause
• ne negates the verb
• propustim is the verb in that clause

English often uses to or so that:

• I check the timetable so that I don’t miss the departure
• I check the timetable not to miss the departure

In Serbian, da + verb is extremely common where English might use an infinitive.

Because Serbian often uses the perfective present after da in purpose clauses when the idea is to prevent or achieve a single result.

Here the desired result is:

• not miss the departure even once, in this specific situation

So propustim works well because it refers to a completed event:

• either I miss it
• or I don’t miss it

Compare the feel:

• da ne propustim polazak — so that I don’t miss the departure
• da ne propuštam polaske — so that I don’t keep missing departures / so that I’m not in the habit of missing departures

So the perfective form fits the one-time, concrete goal.

Yes, propustiti is a perfective verb. Its imperfective partner is usually propuštati.

The difference is:

• propuštati = missing something repeatedly, habitually, or as an ongoing process
• propustiti = to miss something once, as a completed event

Examples:

• Često propuštam autobus. — I often miss the bus.
• Ne želim da propustim autobus. — I don’t want to miss the bus.

In your sentence, the speaker wants to avoid one specific completed outcome: missing the departure. That is why the perfective verb is natural.

Polazak means departure, setting off, or leaving.

Here it is in the accusative singular, but for this masculine inanimate noun, the accusative looks the same as the nominative:

• nominative: polazak
• accusative: polazak

It is the direct object of propustim:

• propustim polazak — miss the departure

This noun is very common in travel contexts:

• vreme polaska — departure time
• mesto polaska — place of departure

Yes, but it would change the meaning slightly.

• da ne propustim polazak = so that I don’t miss the departure
• da ne zakasnim = so that I’m not late

These are related, but not identical:

• if you zakasniš, you arrive late
• if you propustiš polazak, the departure actually leaves without you

So propustim polazak is more specific and stronger in this transport context.

Because Serbian does not have articles like a and the.

Whether something is definite or indefinite is usually understood from:

• context
• word order
• the situation
• sometimes demonstratives like taj, ovaj, onaj

So red vožnje can mean:

• a timetable
• the timetable

And polazak can mean:

• a departure
• the departure

In this sentence, context makes it clear that the speaker means the relevant timetable and the relevant departure.

Yes. Serbian word order is relatively flexible, although some versions sound more natural depending on emphasis.

The original sentence is very natural:

• Usput proveravam red vožnje da ne propustim polazak.

Other possible orders include:

• Proveravam usput red vožnje da ne propustim polazak.
• Da ne propustim polazak, usput proveravam red vožnje.

The difference is mainly about focus:

• starting with usput emphasizes the incidental nature of the action
• starting with da ne propustim polazak emphasizes the purpose
• keeping red vožnje close to proveravam is the most straightforward arrangement

So yes, word order can change, but the original version is a very natural neutral choice.

Yes. Da ne bih propustio / propustila polazak is also possible and can sound a bit more explicitly purposeful or slightly more formal.

Compare:

• da ne propustim polazak — very common, direct, natural
• da ne bih propustio polazak — also common, a little more expanded, often felt as so that I wouldn’t miss the departure

The second version includes:

• bih — a conditional/auxiliary element
• propustio / propustila — past active participle agreeing with the speaker’s gender

So:

• male speaker: da ne bih propustio
• female speaker: da ne bih propustila

In everyday speech, the shorter da ne propustim is often the simplest and most natural choice here.