Der Fahrlehrer sagt, wir sollen immer genug Sicherheitsabstand halten.

German often combines nouns into one compound noun.

• fahren = to drive
• der Lehrer = the teacher

So der Fahrlehrer literally means driving teacher, or more naturally, driving instructor.

The last part of a compound tells you the grammatical gender, so because Lehrer is masculine, the whole word is der Fahrlehrer.

The comma separates two clauses:

• Der Fahrlehrer sagt
• wir sollen immer genug Sicherheitsabstand halten

In English, you might often use that here: The driving instructor says that we should always keep enough safety distance.

German can also use dass:

• Der Fahrlehrer sagt, dass wir immer genug Sicherheitsabstand halten sollen.

But in your sentence, dass is omitted, which is very common in spoken and written German when the meaning is still clear.

Sollen and sollten are related, but they do not mean exactly the same thing.

• wir sollen = we are supposed to / we should
• wir sollten = we should / we ought to, often a bit softer or more like advice

In this sentence, wir sollen fits well because the instructor is giving a rule or instruction. It can sound like reported guidance: He says we are supposed to do this.

So:

• wir sollen = instruction, expectation, rule
• wir sollten = recommendation, often less direct

Here, sollen means something like:

• should
• are supposed to
• are meant to

It is a modal verb. In this sentence, it expresses instruction or obligation coming from another person — the driving instructor.

That is a very common use of sollen: it often suggests that someone else says this is what you must or should do.

Because sollen is a modal verb.

With modal verbs in German, the conjugated modal comes earlier, and the main verb stays in the infinitive at the end of the clause.

Pattern:

• wir sollen ... halten
• ich kann ... fahren
• sie muss ... lernen

So in your sentence:

• sollen = the conjugated modal verb
• halten = the infinitive main verb, placed at the end

Sicherheitsabstand is another compound noun:

• Sicherheit = safety
• Abstand = distance / gap

Together, Sicherheitsabstand means safe distance or following distance, especially in traffic.

German uses compound nouns very freely, so what English often expresses with two words, German often makes into one.

In genug Sicherheitsabstand, German does not need an article.

This works a lot like English:

• enough water
• enough time
• enough distance

Similarly in German:

• genug Wasser
• genug Zeit
• genug Sicherheitsabstand

So Sicherheitsabstand here is being used in a general, uncounted sense. The phrase means enough safety distance, not the safety distance or a safety distance.

Because genug does not change its ending here.

Before a noun, genug is usually invariable:

• genug Zeit
• genug Geld
• genug Abstand
• genug Sicherheitsabstand

So even though Sicherheitsabstand is masculine, you still say genug Sicherheitsabstand, not genugen.

It is in the accusative case, because it is the object of halten in the expression Sicherheitsabstand halten.

You can think of it as the thing being maintained or kept.

Because there is no article, the accusative form is not visibly different here. But grammatically, it is accusative.

Yes, Abstand halten is a very common expression.

It means:

• to keep one’s distance
• to maintain distance

In driving, Sicherheitsabstand halten means to keep a safe following distance.

So this is not just the basic verb halten in the sense of hold. In this expression, halten means maintain or keep.

Immer means always, and it modifies the whole action: always keep enough distance.

German word order is flexible, but this placement is very natural:

• wir sollen immer genug Sicherheitsabstand halten

It groups the sentence neatly like this:

• wir sollen = we should / are supposed to
• immer = always
• genug Sicherheitsabstand = enough safety distance
• halten = keep

So immer comes before the object phrase and emphasizes that this should happen at all times.

Yes.

You can say:

• Der Fahrlehrer sagt, wir sollen immer genug Sicherheitsabstand halten.
• Der Fahrlehrer sagt, dass wir immer genug Sicherheitsabstand halten sollen.

Both are correct.

The version without dass is often a bit more direct and common in everyday speech.
The version with dass is also very normal, and it makes the clause structure more explicit.

Notice that with dass, the word order changes:

• without dass: wir sollen ... halten
• with dass: wir ... halten sollen

That is because a dass-clause sends the finite verb to the end.