Bez względu na to, czy autobus jest pełny, czy prawie pusty, on zawsze czyta w drodze do pracy.

Bez względu na to is a set phrase meaning regardless of that or simply regardless of.

A rough breakdown is:

• bez = without
• względu = regard, consideration
• na = on / to / with respect to
• to = that

So literally it is something like without regard to that, but in normal English you would translate it as regardless of whether...

In this sentence, the whole opening means:

Regardless of whether the bus is full or almost empty...

This is a very common Polish structure.

Here czy ..., czy ... means whether ... or ...

So:

• czy autobus jest pełny = whether the bus is full
• czy prawie pusty = or almost empty

This is different from the other common use of czy, where it introduces a yes/no question, like Czy on czyta? = Is he reading? / Does he read?

In this sentence, czy is not making a question. It is linking two alternatives.

Because Polish often omits repeated words when they are easy to understand from context.

Full version:

• czy autobus jest pełny, czy autobus jest prawie pusty

Natural shortened version:

• czy autobus jest pełny, czy prawie pusty

English does the same thing:

• whether the bus is full or almost empty

So the second half is understood as:

• czy autobus jest prawie pusty

Because they are predicate adjectives used with jest.

The subject is:

• autobus = bus

And after być (to be), adjectives typically appear in the nominative and agree with the subject.

Since autobus is masculine singular, we get:

• pełny = full
• pusty = empty

So:

• autobus jest pełny
• autobus jest pusty

If the noun were different, the adjective form would change to match it.

Usually, on is not necessary.

Polish often drops subject pronouns because the verb ending already tells you who the subject is:

• czyta = he/she/it reads

So a very natural version would be:

• Bez względu na to, czy autobus jest pełny, czy prawie pusty, zawsze czyta w drodze do pracy.

Adding on can sound:

• slightly emphatic
• contrastive
• stylistically deliberate

For example, it might suggest something like:

• He, for his part, always reads...
• As for him, he always reads...

So on is grammatically fine, but not required.

Because that is a very natural word order for an adverb like zawsze.

• on zawsze czyta = he always reads

Polish word order is flexible, but not random. The position of zawsze before the verb is neutral and common.

Other orders are possible, but they may shift emphasis:

• On zawsze czyta... = neutral
• On czyta zawsze... = more marked, less neutral in many contexts

So the version in the sentence is the most straightforward one.

Because in Polish, the present tense of an imperfective verb is used for:

• actions happening now
• habitual actions
• repeated routines

The verb czytać is imperfective, and czyta means:

• he reads
• he is reading
  depending on context

Here, because of zawsze and the general meaning of the sentence, it clearly describes a habit:

• he always reads on the way to work

So this is normal Polish usage.

W drodze do pracy is a very common expression meaning:

• on the way to work
• while going to work
• during the trip to work

Breakdown:

• w drodze = on the way / en route
• do pracy = to work

It refers to the journey or commute, not the workplace itself.

So he is reading while traveling to work, not at work.

Because w drodze is a fixed idiomatic expression.

Literally, droga means road or way, and:

• w drodze = in the course of the journey / on the way

This phrase uses the locative after w, so droga becomes drodze.

You should learn w drodze as a whole expression, because it is much more idiomatic than trying to build it word by word.

Do takes the genitive case.

The noun is:

• praca = work

In the genitive singular, it becomes:

• pracy

So:

• do pracy = to work

This expresses movement toward a destination. In the full phrase w drodze do pracy, it means on the way to work.

Prawie means almost or nearly.

So:

• pusty = empty
• prawie pusty = almost empty / nearly empty

Here prawie modifies the adjective pusty.

The contrast in the sentence is between:

• pełny = full
• prawie pusty = almost empty

That makes the meaning more natural than saying the bus is completely empty.

Because the opening part is a subordinate clause-like construction that sets up the condition or contrast:

• Bez względu na to, czy autobus jest pełny, czy prawie pusty, ...

Polish punctuation often separates this kind of introductory structure with commas.

So the commas mark:

1. the start of the czy ... czy ... part after na to
2. the separation between the two alternatives
3. the end of the introductory section before the main clause

Then the main clause begins:

• on zawsze czyta w drodze do pracy

Not with exactly the same meaning.

If you remove bez względu na to, you lose the idea of regardless of. The sentence would no longer mean that the bus being full or almost empty makes no difference.

So this part is important because it introduces the idea:

• no matter whether
• regardless of whether

A common alternative would be:

• Niezależnie od tego, czy autobus jest pełny, czy prawie pusty, on zawsze czyta w drodze do pracy.

That means almost the same thing.

Yes, it is natural and understandable.

A slightly more neutral everyday version might omit on:

• Bez względu na to, czy autobus jest pełny, czy prawie pusty, zawsze czyta w drodze do pracy.

But the original sentence is still correct. The version with on simply gives a bit more emphasis to he.