Im Rückspiegel sieht sie, dass hinter ihr schon ein Bus wartet, also dreht sie das Lenkrad vorsichtig.

German often puts a time, place, or context phrase first for emphasis or to set the scene.

• Im Rückspiegel = in dem Rückspiegel = in the rear-view mirror
• By putting it first, the sentence immediately tells us where she sees this.

This is very natural in German. English can also do this:

• In the rear-view mirror, she sees...

So this is not unusual or poetic — just normal German word order.

Im is a very common contraction:

• in dem → im

So:

• im Rückspiegel = in the rear-view mirror

German uses this contraction all the time when it sounds natural. It is standard, not informal.

Because German main clauses follow the verb-second rule.

The first position is taken by Im Rückspiegel, so the conjugated verb must come next:

• Im Rückspiegel | sieht | sie

If the sentence started with sie, then it would be:

• Sie sieht im Rückspiegel, ...

Both are correct. The difference is just what comes first.

Dass means that and introduces a subordinate clause.

In German, when a clause begins with a subordinating conjunction like dass, the conjugated verb usually goes to the end of that clause.

So:

• dass hinter ihr schon ein Bus wartet

Structure:

• dass = that
• hinter ihr = behind her
• schon = already
• ein Bus = a bus
• wartet = is waiting / waits

This is one of the most important German word-order patterns to learn.

Because hinter is one of the two-way prepositions. It can take:

• accusative for direction/movement toward somewhere
• dative for location/position

Here, the bus is located behind her, not moving to a position behind her. So German uses dative:

• hinter ihr = behind her

Compare:

• Der Bus steht hinter ihr. = The bus is behind her. → dative
• Der Bus fährt hinter sie. = The bus drives to a position behind her. → this would be a movement idea, though this particular phrasing is not very natural

Also, ihr here is the dative form of sie.

Here schon means something like:

• already
• by now

So dass hinter ihr schon ein Bus wartet suggests that a bus is already waiting behind her, perhaps sooner than expected or as part of a developing situation.

It adds a slight nuance of:

• this is already happening
• the situation is becoming urgent or noticeable

German punctuation is stricter than English in some places.

1. Before dass A subordinate clause introduced by dass must be separated by a comma:

• ..., dass hinter ihr schon ein Bus wartet

2. Before also Here also connects two main clauses, so a comma is used:

• ..., also dreht sie das Lenkrad vorsichtig.

This comma helps show the structure clearly.

Here also means:

• so
• therefore
• thus

It shows a consequence:

• She sees a bus is already waiting behind her, so she carefully turns the steering wheel.

Important: this is not the same as the English filler word “also” meaning “too”. In German, also usually means so / therefore / well then, depending on context.

Because also is occupying the first position of the second main clause, and German main clauses still follow the verb-second rule.

So:

• also | dreht | sie | das Lenkrad | vorsichtig

If you removed also, you would get:

• Sie dreht das Lenkrad vorsichtig.

This same pattern happens with many connectors and adverbs, such as:

• Dann geht er nach Hause.
• Deshalb bleibt sie hier.

Das Lenkrad is the direct object of dreht.

• drehen = to turn
• das Lenkrad drehen = to turn the steering wheel

Because it is the direct object, it is in the accusative case. But das stays das in both nominative and accusative singular, so the form does not change.

Because vorsichtig is acting as an adverb, not an adjective describing a noun.

It describes how she turns the steering wheel:

• Sie dreht das Lenkrad vorsichtig. = She carefully turns the steering wheel.

Adverbs in German do not take adjective endings.

Compare:

• ein vorsichtiger Fahrer = a careful driver
  (vorsichtiger describes a noun, so it gets an ending)
• Er fährt vorsichtig. = He drives carefully
  (vorsichtig describes the verb, so no ending)

Yes. German often uses the simple present tense where English uses either:

• waits
• is waiting

So:

• ein Bus wartet can mean a bus waits or, more naturally in English here, a bus is waiting

German does not need a special progressive form like English is waiting in most cases.

In form, sie can mean several things in German:

• she
• they
• you (formal, written Sie)

But here the meaning is clearly she because of the context and the rest of the sentence:

• Im Rückspiegel sieht sie...
• hinter ihr...
• also dreht sie...

The pronoun ihr also points back to a singular feminine person here: behind her.

Yes, absolutely.

Both are correct:

• Im Rückspiegel sieht sie, dass ...
• Sie sieht im Rückspiegel, dass ...

The difference is mainly emphasis and flow:

• Im Rückspiegel sieht sie... emphasizes the location first
• Sie sieht im Rückspiegel... starts with the person doing the action

German is more flexible than English about what can come first, as long as the verb-second rule is respected in main clauses.