Learn Hardcore German: Beim zweiten Unfall zeigt die Fahrerin dem Zeugen sofort ihre Versicherungskarte. - At the second accident the female driver immediately shows the witness her insurance card.

bei is a preposition that always takes the dative case.
dem is the dative singular article for masculine and neuter nouns (here: dem Unfall).

So:

bei dem zweiten Unfall → beim zweiten Unfall

In normal spoken and written German, bei dem is almost always shortened to beim unless you want special emphasis on dem (very rare in this context).

Why is it zweiten Unfall and not zweite Unfall?

Because zweiten is in the dative case and must agree with Unfall and its article.

We have:

Preposition bei → always dative.
Noun Unfall → masculine.
Definite article (masc. dat. sg.) → dem (inside beim).
Adjective after a definite article, masculine dative singular → ending -en.

So the pattern is:

bei dem zweiten Unfall
- bei (dative)
- dem (masc. dat. sg.)
- zweiten (adjective in dative after a definite article)
- Unfall (noun)

That’s why you need zweiten, not zweite.

Why is Unfall in the dative case?

Unfall is in the dative because it is governed by the preposition bei.

In German, each preposition requires a specific case. Bei always takes the dative:

bei dem Arzt (at the doctor’s)
bei der Arbeit (at work)
bei den Eltern (at the parents’ place)
bei dem Unfall → beim Unfall

So Unfall is dative not because of its role (it’s not an indirect object), but purely because bei demands dative.

Why does the verb zeigt come right after Beim zweiten Unfall and before die Fahrerin?

German main clauses follow the verb‑second (V2) rule: the finite verb (here zeigt) must be the second element in the sentence.

You can place different elements in the first position for emphasis. Here, the first element is the prepositional phrase:

Beim zweiten Unfall – first position
zeigt – finite verb, second position
die Fahrerin – subject comes after the verb

If you started with the subject instead, you would still keep the verb second:

Die Fahrerin zeigt dem Zeugen sofort ihre Versicherungskarte beim zweiten Unfall.

The subject doesn’t have to come first; the finite verb just has to be in second position.

Why is it die Fahrerin and not der Fahrer?

Fahrerin is the specifically feminine form of Fahrer.

Fahrer = (male/unspecified) driver
Fahrerin = female driver (the -in ending marks feminine for many professions and roles)

Because we are explicitly talking about a woman, the sentence uses Fahrerin with the feminine article die:

die Fahrerin (feminine nominative singular)
der Fahrer (masculine nominative singular)

Why is it dem Zeugen and not den Zeugen?

Dem Zeugen is dative singular; den Zeugen would be accusative singular (or dative plural).

Here, der Zeuge (the witness) is the indirect object – the person who receives something (the card). In German, indirect objects are usually in the dative case.

The verb pattern is:

jemandem etwas zeigen
(to show somebody something)

So:

die Fahrerin – subject (nominative)
dem Zeugen – indirect object (dative)
ihre Versicherungskarte – direct object (accusative)

For a masculine noun:

nominative: der Zeuge
accusative: den Zeugen
dative: dem Zeugen

Because we need dative, the correct form is dem Zeugen.

How can I tell which parts are subject, indirect object, and direct object in this sentence?

Look at the cases and the verb:

Verb pattern:
jemandem etwas zeigen
→ show somebody (dative) something (accusative)
Identify the cases:

die Fahrerin
- Article die for a singular noun at the start of a main clause is usually nominative feminine.
- Likely the subject.
dem Zeugen
- Article dem = dative singular (masc./neuter).
- Likely the indirect object (the person to whom something is shown).
ihre Versicherungskarte
- ihre here functions like eine with an -e ending → accusative feminine singular.
- This fits the direct object (the thing that is shown).

So:

Subject (nominative): die Fahrerin
Indirect object (dative): dem Zeugen
Direct object (accusative): ihre Versicherungskarte

What does sofort mean, and where can it appear in the sentence?

Sofort means immediately / right away.

In terms of word order, sofort is a relatively flexible adverb. In this sentence it sits in the middle field:

… zeigt die Fahrerin dem Zeugen sofort ihre Versicherungskarte.

Other natural positions include:

… zeigt die Fahrerin sofort dem Zeugen ihre Versicherungskarte.
… zeigt die Fahrerin dem Zeugen ihre Versicherungskarte sofort. (sounds more emphatic, “the card immediately”)

What you normally wouldn’t do is put sofort at the very end unless you want strong emphasis, and you usually keep it somewhere near the verb or objects.

What exactly does ihre mean here, and how do I know it refers to the driver and not the witness?

Ihre is a possessive pronoun meaning her (or their, depending on context).

There are two steps to understand it:

Possessor (who owns the thing?)
- ihr- base form is used when the possessor is feminine singular or plural.
- sein- is used when the possessor is masculine or neuter singular.
The subject die Fahrerin is feminine, so ihr- (→ ihre) naturally refers to her card.
Form of the ending (what does it attach to?)
- Versicherungskarte is feminine accusative singular (direct object).
- Possessive for fem. acc. sg. → ihre (ending -e).

So ihre Versicherungskarte = her insurance card, and by default ihre refers back to the subject die Fahrerin unless context clearly says otherwise.

Why is it ihre Versicherungskarte and not ihrer Versicherungskarte?

Because Versicherungskarte is the direct object and thus in the accusative, not the dative.

Compare:

Feminine accusative singular:
- article: die
- possessive (her): ihre
Feminine dative singular:
- article: der
- possessive (her): ihrer

The verb pattern is:

jemandem etwas zeigen
→ dative for the person, accusative for the thing.

So:

Dative: dem Zeugen (the person)
Accusative: ihre Versicherungskarte (the thing)

Therefore we need ihre, not ihrer.

Can I start the sentence with Die Fahrerin instead? What other word orders are possible?

Yes. You can rearrange several elements as long as:

The finite verb stays in second position.
The cases remain the same, so the roles are still clear.

Some natural alternatives:

Die Fahrerin zeigt dem Zeugen beim zweiten Unfall sofort ihre Versicherungskarte.
Die Fahrerin zeigt dem Zeugen sofort beim zweiten Unfall ihre Versicherungskarte.
Die Fahrerin zeigt beim zweiten Unfall dem Zeugen sofort ihre Versicherungskarte.
Dem Zeugen zeigt die Fahrerin beim zweiten Unfall sofort ihre Versicherungskarte. (emphasis on the witness)

The original:

Beim zweiten Unfall zeigt die Fahrerin dem Zeugen sofort ihre Versicherungskarte.

puts particular emphasis on the time/occasion (beim zweiten Unfall). All are grammatically correct; the differences are mainly in emphasis and style.

What does the compound noun Versicherungskarte literally mean, and are such compounds common in German?

Versicherungskarte is a compound of:

Versicherung – insurance
Karte – card

So literally it’s an “insurance card”.

Such compounds are extremely common in German. You often see:

Fahrkarte (travel ticket – literally “driving card”)
Krankenversicherung (health insurance – “sickness insurance”)
Kreditkarte (credit card)
Mitgliedskarte (membership card)

German freely combines nouns into longer compounds, usually written as a single word, with the main noun at the end (here, Karte is the main noun).