De reiziger vóór ons had haar instapkaart al in de hand, daardoor ging de veiligheidscontrole veel sneller.

Yes. Haar means her, so the sentence tells you that the traveler was female.

Dutch often uses natural gender with possessives:

• zijn instapkaart = his boarding pass
• haar instapkaart = her boarding pass

So even though de reiziger can mean the traveler in a general sense, haar makes it specific here.

Here vóór ons means in front of us: the traveler was ahead of us in the line.

So:

• de reiziger vóór ons = the traveler in front of us

In other contexts, voor can also mean for or before, but here the meaning is clearly spatial.

The accents in vóór help show the meaning more clearly or add emphasis. You may also see voor ons without accents in ordinary writing.

Because ons is the form used after a preposition such as voor/vóór.

Compare:

• wij = we (subject)
• ons = us (object form, also used after prepositions)

So:

• wij wachten = we are waiting
• vóór ons = in front of us

This is similar to English we vs us.

Al here means already.

So:

• had haar instapkaart al in de hand = already had her boarding pass in her hand

It suggests she was prepared before it was her turn, which explains why things moved faster.

Because Dutch very often makes compound nouns by joining words together.

Here:

• instap = boarding
• kaart = card/ticket

So instapkaart means boarding pass.

This is very normal in Dutch. English often writes these as two words, but Dutch usually combines them:

• veiligheidscontrole
• treinstation
• paspoortcontrole

Literally, it means in the hand.

In this sentence, haar instapkaart al in de hand hebben means she was physically holding the boarding pass, or at least had it ready in her hand.

It implies preparedness. A natural English idea would be:

• to have something ready in your hand
• to already be holding something

Because Dutch main clauses follow the verb-second rule.

If a different element comes first, the finite verb must still stay in second position.

So:

• De veiligheidscontrole ging daardoor veel sneller.
• Daardoor ging de veiligheidscontrole veel sneller.

Both are correct, but when daardoor is moved to the front, the verb ging must come immediately after it.

This is a very common Dutch word order pattern.

Daardoor means because of that, as a result, or thereby.

It points back to the previous fact:

• she already had her boarding pass ready
• daardoor the security check went faster

Rough comparison:

• daardoor = because of that / as a result of that
• daarom = for that reason
• dus = so

In this sentence, daardoor fits well because it emphasizes a direct consequence.

Yes, gaan usually means to go, but it is also used in Dutch in expressions about how a process proceeds.

Here:

• de veiligheidscontrole ging veel sneller
  means
• the security check went much faster

This is very close to English, where went can also describe how something proceeded:

• The meeting went well
• The process went faster than expected

So ging is not about physical movement here.

Yes. With a comparative adjective, veel means much or a lot.

So:

• sneller = faster
• veel sneller = much faster

Compare:

• snel = fast
• sneller = faster
• veel sneller = much faster

This is just like English:

• good
• better
• much better

Veiligheidscontrole means security check or security screening.

It is another Dutch compound:

• veiligheid = safety/security
• controle = check/inspection

In an airport context, it refers to the process of going through security.

Yes, the comma is natural.

The sentence contains two main clauses:

• De reiziger vóór ons had haar instapkaart al in de hand
• daardoor ging de veiligheidscontrole veel sneller

Dutch often links such clauses with a comma, especially when the second clause begins with a linking word like daardoor.

You could also write it as two sentences:

• De reiziger vóór ons had haar instapkaart al in de hand. Daardoor ging de veiligheidscontrole veel sneller.

Both are fine; the version with the comma feels smoothly connected.