Wegen einer Umleitung hält der Bus heute nicht an unserer Bushaltestelle.

German often puts the element you want to emphasize first. Here, Wegen einer Umleitung gives the reason right away: Because of a diversion...

In a normal main clause, German still follows the verb-second rule, so the conjugated verb must come next:

• Wegen einer Umleitung | hält | der Bus ...
• first position | second position | then the subject

If you started with the subject instead, that would also be correct:

• Der Bus hält heute wegen einer Umleitung nicht an unserer Bushaltestelle.

Both are grammatical; the original just emphasizes the reason first.

Because der Bus is third person singular, so the verb must be conjugated accordingly.

The infinitive is halten = to stop.
Its present-tense forms include:

• ich halte
• du hältst
• er/sie/es hält
• wir halten
• ihr haltet
• sie/Sie halten

So with der Bus, you need hält.

Also notice that halten is a strong verb, so its stem vowel changes from a to ä in the du and er/sie/es forms.

Wegen usually takes the genitive in standard German.

So:

• wegen einer Umleitung = because of a diversion

Here, Umleitung is a feminine noun: die Umleitung.

The feminine singular genitive article is einer, so:

• nominative: eine Umleitung
• genitive: einer Umleitung

This can be confusing because einer is also the feminine dative form, but here it is functioning as genitive after wegen.

You may also hear dative after wegen in informal speech, but learners should generally treat wegen as a genitive preposition.

Because many feminine nouns in German do not add an extra ending in the genitive singular.

So:

• nominative: die Umleitung
• genitive: der Umleitung / with an indefinite article: einer Umleitung

The noun itself stays Umleitung.

By contrast, many masculine and neuter nouns often add -s or -es in the genitive, such as:

• wegen des Busses
• wegen des Kindes

Because der Bus is the subject of the sentence, and subjects are in the nominative case.

Ask: Who is doing the action?
Answer: der Bus

So:

• nominative: der Bus
• accusative: den Bus

Since the bus is the thing that stops, not the direct object, nominative is correct.

This comes from the expression anhalten an + dative, which means to stop at a place.

So:

• anhalten an einer Haltestelle = to stop at a stop

Here, Bushaltestelle is feminine:

• die Bushaltestelle

After an in this meaning, German uses the dative, so:

• an unserer Bushaltestelle

The article/adjective form unserer shows feminine singular dative.

Because with anhalten meaning to stop at a place/stop, German idiomatically uses an.

So the natural expression is:

• Der Bus hält an der Haltestelle.

Using in would usually suggest being inside something, which does not fit here.
Using bei can sometimes mean near or by, but it is not the standard choice for a bus stopping at a stop.

So this is something to learn as a fixed pattern:

• halten / anhalten an + dative

Because Bushaltestelle is feminine singular, and after an here you need the dative case.

The phrase is based on:

• an der Bushaltestelle = at the bus stop

When you replace der with unsere, it must take the matching dative feminine ending:

• an unserer Bushaltestelle

So the breakdown is:

• unsere = our
• dative feminine singular form = unserer

In German, nicht usually comes before the part of the sentence it is negating.

Here, the idea is:

• the bus does not stop at our bus stop

So nicht is placed before the location phrase:

• ... hält der Bus heute nicht an unserer Bushaltestelle.

This means the negation mainly applies to the stopping there.

Compare:

• Der Bus hält heute nicht an unserer Bushaltestelle.
  = It does not stop at our bus stop.

If nicht were placed differently, the emphasis could change.

Yes. Heute is a time adverb meaning today, and German allows some flexibility with adverb placement.

In the original:

• Wegen einer Umleitung hält der Bus heute nicht an unserer Bushaltestelle.

That is perfectly natural.

You could also say:

• Heute hält der Bus wegen einer Umleitung nicht an unserer Bushaltestelle.
• Der Bus hält heute wegen einer Umleitung nicht an unserer Bushaltestelle.

The exact position can shift depending on what you want to emphasize, but the verb still stays in second position in a main clause.

Umleitung means diversion, detour, or rerouting, depending on context.

In traffic or public transport, it usually means that the normal route is temporarily changed, for example because of:

• roadworks
• an accident
• an event
• a closure

So in this sentence, the bus is not stopping at the usual bus stop because it is following a different route.

Yes, it is one word, and that is very normal in German.

German often forms compound nouns by joining smaller nouns together:

• Bus = bus
• Haltestelle = stop
• Bushaltestelle = bus stop

The last part usually determines the grammatical gender, so because die Haltestelle is feminine, die Bushaltestelle is also feminine.

Yes, and the meaning would be very similar.

You can say:

• Der Bus hält an unserer Bushaltestelle.
• Der Bus hält heute nicht an unserer Bushaltestelle.

And also:

• Der Bus hält heute nicht an unserer Bushaltestelle an.

The version with anhalten is a separable verb, so in a main clause the prefix goes to the end:

• Der Bus hält ... an.

In everyday transport announcements, halten an is very common and natural.

You usually learn the noun together with its article:

• die Bushaltestelle

Also, the ending -stelle is often feminine, because die Stelle is feminine.

Once you know it is feminine, the other forms make sense:

• nominative: die Bushaltestelle
• dative: der Bushaltestelle
• with unsere in dative: unserer Bushaltestelle

That is why the sentence says an unserer Bushaltestelle.