Learn Hardcore Greek: Είναι πιο ασφαλές να περνάς τον δρόμο μαζί με άλλους πεζούς. - It is safer to cross the road together with other pedestrians.

Because the subject is a general idea (the whole action να περνάς τον δρόμο μαζί με άλλους πεζούς), Greek uses the neuter singular adjective to agree with this abstract idea. So:

είναι ασφαλές = it is safe
είναι πιο ασφαλές = it is safer

You would not use πιο ασφαλή here, because that is not the neuter singular form; πιο ασφαλή might be masculine/feminine plural in other contexts, but here we need neuter singular.

What exactly does είναι mean here? Is it like the English “it is”?

Yes. Είναι is the 3rd person singular form of είμαι (to be): he/she/it is or simply is.

In English, we say:

It is safer to cross the road with other pedestrians.

Greek does not need an explicit “it”:

Είναι πιο ασφαλές να περνάς…
literally: Is safer to cross…

So είναι here is an impersonal “is”, equivalent to “it is” in English.

Why do we use πιο ασφαλές instead of just ασφαλές?

Πιο means more, and it forms a comparative:

ασφαλές = safe
πιο ασφαλές = safer / more safe

The sentence is saying that this way of crossing is safer than another way (for example, crossing alone). If you just said:

Είναι ασφαλές να περνάς τον δρόμο μαζί με άλλους πεζούς.
= It is safe to cross the road with other pedestrians.

you would only state that it is safe, not that it is safer (in comparison).

You could also use the synthetic comparative:

ασφαλέστερο = safer

So:

Είναι ασφαλέστερο να περνάς… is also correct, just a bit more formal/literary.

What is να περνάς grammatically? Why this form and not an infinitive?

Modern Greek does not have an infinitive like English to cross.

Instead, Greek uses να + verb (the “subjunctive” form) where English would use an infinitive. So:

να περνάς ≈ to cross (in a general/habitual sense here)

This να-clause functions like a verbal noun phrase:

Είναι πιο ασφαλές να περνάς τον δρόμο…
≈ It is safer *to cross the road…*

So να περνάς is the present subjunctive, 2nd person singular of the verb περνάω/περνώ (to pass, to cross [a road]).

Why is it να περνάς and not να περάσεις?

Both come from the same verb περνάω/περνώ, but:

να περνάς = present subjunctive (imperfective aspect)
→ focuses on the action in general / as a process / habit
να περάσεις = aorist subjunctive (perfective aspect)
→ focuses on a single, complete crossing

In this sentence, we’re talking about the general way it is safer to cross roads (any time, as a rule), so Greek prefers the imperfective:

Είναι πιο ασφαλές να περνάς τον δρόμο μαζί με άλλους πεζούς.
= It is safer (in general) to cross the road with other pedestrians.

If you used να περάσεις, it would sound more like advice about a specific instance of crossing, not a general rule.

Why second person singular περνάς? Are we talking to “you” specifically or people in general?

The 2nd person singular (περνάς) is often used in Greek to express general statements about people, similar to English “you” in:

When you drive fast, you’re in more danger.

So:

Είναι πιο ασφαλές να περνάς τον δρόμο…
literally: It is safer that you cross the road…
but really means: It is safer to cross the road… / One is safer crossing the road…

You could also use:

να περνάμε (we) or
να περνάει κανείς (one)

but να περνάς is very natural, conversational Greek for a general rule/advice.

Could we also say να περνάτε instead of να περνάς?

Yes, να περνάτε (2nd person plural) is also possible. It would sound more like:

talking formally/politely to one person, or
talking to a group (you all)

So:

Είναι πιο ασφαλές να περνάτε τον δρόμο μαζί με άλλους πεζούς.
= It is safer for you (all) to cross the road with other pedestrians.

The meaning of the structure is the same; you only change who you are addressing (informal singular περνάς vs plural/polite περνάτε).

Why do we say τον δρόμο and not just δρόμο without the article?

Τον δρόμο is accusative singular with the definite article:

ο δρόμος (nom.) → τον δρόμο (acc.)

In Greek, the definite article is used much more often than in English, even with general statements. So:

να περνάς τον δρόμο
literally: to cross *the road
but it often means *to cross roads / the road in general.

You can say να περνάς δρόμο in some contexts, but here it would sound strange or incomplete. The article is normal and natural when talking about the typical object of the action (e.g. παίρνω το λεωφορείο, κλείνω την πόρτα, περνάω τον δρόμο).

What case are τον δρόμο and άλλους πεζούς, and why?

Both τον δρόμο and άλλους πεζούς are in the accusative case:

τον δρόμο: masculine singular accusative → direct object of περνάς
άλλους πεζούς: masculine plural accusative → object of the preposition με

In Greek:

Direct objects of verbs are in the accusative.
Most prepositions (like με) also require the accusative.

So:

περνάς τον δρόμο → you cross the road (accusative object)
μαζί με άλλους πεζούς → together with other pedestrians (accusative after με)

Why do we say μαζί με? Would just με άλλους πεζούς be enough?

μαζί = together
με = with

Μαζί με literally means “together with”, and the combination is very common in Greek.

You could say only:

με άλλους πεζούς = with other pedestrians

and it would still be understandable. However:

μαζί με άλλους πεζούς adds the idea of in their company / as part of a group, not just “accompanied by them” in some abstract sense.

So μαζί με is more natural when you want to stress being among them, crossing as a group.

What is πεζούς? Is it an adjective or a noun?

Πεζούς here is a noun meaning pedestrians.

The base form is:

ο πεζός = the pedestrian (masculine singular)
οι πεζοί = the pedestrians (masculine plural)

In the sentence we have:

άλλους πεζούς = other pedestrians

This is masculine plural accusative:

άλλοι πεζοί (nom. pl.) → άλλους πεζούς (acc. pl.)

So άλλους is an adjective (other) agreeing in gender/number/case with the noun πεζούς.

Is the word order fixed? Could I say …να περνάς μαζί με άλλους πεζούς τον δρόμο instead?

Greek word order is quite flexible, so these are all possible:

να περνάς τον δρόμο μαζί με άλλους πεζούς
να περνάς μαζί με άλλους πεζούς τον δρόμο

Both are correct and natural. The usual, neutral order is:

verb + direct object (περνάς τον δρόμο)
then the phrase of company/manner (μαζί με άλλους πεζούς)

Changing the order can slightly change emphasis, but not the basic meaning. In everyday speech, the original order (τον δρόμο before μαζί με άλλους πεζούς) is probably the most typical.

Why is there no comma before να? In English we might pause: “It is safer, to cross the road…”

In Greek, you normally do not put a comma before να when it introduces a clause like this:

Είναι πιο ασφαλές να περνάς τον δρόμο…

The να-clause is tightly connected to the verb είναι, functioning almost like its complement:

Είναι [τι;] → να περνάς τον δρόμο…

So no comma is needed. In fact, a comma there would usually be considered wrong in standard punctuation.

In English we also usually don’t write a comma there:
It is safer to cross the road with other pedestrians.