Na tom smjerokazu piše da je zastoj na cesti, zato svi skreću prema selu.

Because na means on here, and it is describing a location, not movement. With that meaning, na takes the locative case.

So:

• smjerokaz = direction sign, signpost
• smjerokazu = locative singular of smjerokaz

So na tom smjerokazu means on that sign.

Because taj is the basic dictionary form, but after a preposition it has to change case.

Here the noun is in the locative, so the demonstrative must match it:

• nominative: taj smjerokaz = that sign
• locative: na tom smjerokazu = on that sign

You may also see na tome smjerokazu. Both tom and tome are possible, but tom is very common in everyday Croatian.

Smjerokaz is a direction sign or signpost. It usually gives directions or points drivers toward a place.

It is more specific than a general znak (sign). In this sentence, it suggests a road sign giving information to drivers.

Here piše does not mean that someone is physically writing at that moment. In this kind of sentence, piše means:

• it says
• it is written
• it reads

So Na tom smjerokazu piše... means On that sign it says...

This is a very common Croatian way to talk about written text:

• Na vratima piše... = On the door it says...
• U poruci piše... = In the message it says...

Croatian does not need a dummy subject like English there in sentences such as there is / there are.

So:

• da je zastoj na cesti literally looks like that is a traffic jam on the road
• but natural English is that there is a traffic jam on the road

Croatian often expresses existence just with je (is) plus the noun:

• Na cesti je zastoj. = There is a traffic jam on the road.

So the English there is not translated directly.

In road traffic, zastoj means a traffic jam, hold-up, delay, or standstill.

The core idea is that movement is slowed or stopped. In other contexts, zastoj can also mean a stoppage or interruption in a more general sense.

Here, because of na cesti, the meaning is clearly road-related: a traffic hold-up / traffic jam.

Because Croatian normally uses na with cesta when talking about something happening on the road.

So:

• na cesti = on the road
• cesti = locative singular of cesta

This is the natural preposition here because a road is viewed as a surface or route.

Compare:

• zastoj na cesti = a traffic jam on the road
• auto je na cesti = the car is on the road

Here zato means therefore, so, or that’s why.

It introduces the result of the previous clause:

• the sign says there is a traffic jam
• therefore / so everyone turns toward the village

So the logic is: There is a traffic jam on the road, so everyone turns toward the village.

Svi means everyone or all of them.

In this sentence, it probably refers to drivers or people in traffic, but Croatian often leaves that kind of noun understood from context.

So svi skreću means:

• everyone is turning
• all of them are turning

Croatian often omits an obvious noun if the situation already makes it clear.

Because the subject is svi, which is plural in meaning: everyone / all of them.

So:

• svi = plural meaning
• skreću = they turn / are turning

This is normal agreement:

• svi dolaze = everyone is coming
• svi čekaju = everyone is waiting

This is mainly about aspect.

• skreću comes from the imperfective verb skretati
• skrenu comes from the perfective verb skrenuti

In this sentence, skreću is used because the action is seen as:

• ongoing,
• in progress,
• or as a general reaction happening right now.

So svi skreću prema selu is like:

• everyone is turning toward the village
• everyone turns toward the village

Using skrenu here would not sound right in the same way, because perfective present usually does not describe an ongoing present action.

The preposition prema takes the dative case, so:

• selo = village
• selu = dative singular

So:

• prema selu = toward the village / in the direction of the village

This is important because prema selu does not necessarily mean they enter the village. It only gives the direction.

Compare:

• prema selu = toward the village
• u selo = into the village

Yes. Croatian word order is more flexible than English word order because case endings show the grammatical relationships.

For example, these are possible:

• Na tom smjerokazu piše da je zastoj na cesti...
• Piše na tom smjerokazu da je zastoj na cesti...

The original order sounds natural because it starts with the place where the information appears: on that sign.

So the chosen order helps set the scene first, and then gives the message.

Because the sentence contains two main clauses:

1. Na tom smjerokazu piše da je zastoj na cesti
2. zato svi skreću prema selu

The second clause gives the consequence of the first one, and in standard writing Croatian normally separates that with a comma.

So the comma works much like in English:

• There is a traffic jam on the road, so everyone turns toward the village.