ziko de zyuutaisite ite, mokutekiti made itizikan mo kakatta ndesu.

Here, で marks the cause/reason.

So 事故で means because of an accident or due to an accident.

In this sentence, it is not the location marker で. Japanese で has several uses, and one common use is to show a cause, especially for things like:

• 事故で = due to an accident
• 病気で = because of illness
• 大雨で = due to heavy rain

So 事故で渋滞していて means something like there was traffic congestion because of an accident.

渋滞 is a noun meaning traffic jam / congestion, but it can also be used with する as a verbal expression:

• 渋滞する = to be congested / to be backed up with traffic

From there:

• 渋滞している = is congested / is jammed
• 渋滞していて = being congested, and... / because it was congested...

So in this sentence, 渋滞していて is the て-form of 渋滞している, used to connect to the next part of the sentence.

Because the speaker wants to connect that idea to what comes next.

• 渋滞していた。 = It was congested.
• 渋滞していて、目的地まで一時間もかかった。 = It was congested, and/because of that, it took as much as an hour to get to the destination.

The て-form often links clauses and can imply:

• simple connection: and
• reason/cause: because / since
• background situation

Here it strongly suggests a reason: Because there was traffic congestion due to an accident, it took a whole hour to get to the destination.

It can suggest either, depending on context, but here it most naturally means because there was traffic congestion.

The sentence flow is:

• 事故で渋滞していて
• 目的地まで一時間もかかったんです

So the congestion is clearly the reason it took so long. In English, the most natural translation would usually use because.

目的地 means destination.

まで means up to / until / as far as.

So:

• 目的地まで = to the destination / as far as the destination

It marks the end point of movement or extent.

Compare:

• 目的地に着いた = arrived at the destination
• 目的地まで一時間かかった = it took one hour to get to the destination

So まで focuses on the span or endpoint of the trip.

This も adds emphasis. It means something like:

• as much as an hour
• a whole hour

So:

• 一時間かかった = it took one hour
• 一時間もかかった = it took a whole hour / it took as much as an hour

This often suggests the speaker feels that amount is surprisingly long, more than expected, or a lot in the situation.

So 一時間もかかった has a tone like: Can you believe it took a whole hour?

It is the same particle, but the function is different.

Japanese particles often have more than one use. Here, も does not mean also. Instead, it adds emphasis to the amount.

Common examples:

• 三回も読んだ = I read it as many as three times
• 千円もした = It cost as much as 1,000 yen
• 一時間もかかった = It took a whole hour

So this is an emphatic も, not an also/too も.

It comes from かかる, which often means to take when talking about time or money.

Examples:

• 時間がかかる = time is required / it takes time
• お金がかかる = money is required / it costs money

So:

• 一時間かかった = it took one hour

In this sentence, かかった is past tense, because the trip already happened.

Because かかる is the natural verb used for time being required.

• 一時間かかった = It took one hour

Japanese treats this a bit differently from English. English says it took an hour, but Japanese often uses かかる, an intransitive verb meaning that time was required.

So the sentence is not really saying someone took an hour in the active sense. It is saying an hour was needed to get there.

んです adds an explanatory or background-giving tone.

Compare:

• 一時間もかかった。 = It took a whole hour.
• 一時間もかかったんです。 = It took a whole hour, you see. / The thing is, it took a whole hour.

It often sounds like the speaker is:

• explaining a situation
• giving a reason
• adding background
• expressing mild emotion or emphasis

In this sentence, it fits very naturally because the speaker is explaining why things took so long.

This is a very common question.

In Japanese, when clauses are linked with the て-form, the tense is often mainly shown by the final verb. The earlier clause gets its time from the overall context.

So:

• 事故で渋滞していて、目的地まで一時間もかかった。

naturally means:

• There was traffic congestion because of an accident, and it took a whole hour to get to the destination.

Even though していて itself does not look past, the sentence as a whole is understood as describing a past situation because of かかった.

Yes, most likely.

Japanese often leaves out subjects when they are obvious from context. This sentence does not explicitly say:

• who was traveling
• what took an hour

Depending on context, the omitted idea could be something like:

• we
• I
• the trip
• the drive
• it

English usually needs a subject, but Japanese often does not.

So the sentence could be understood as:

• Because of an accident, there was traffic, and it took us a whole hour to get to the destination.
• Because of an accident, traffic was backed up, so it took a whole hour to reach the destination.

Yes, that is a very natural way to understand the first part.

• 事故で渋滞していて = There was a traffic jam because of an accident / Traffic was backed up because of an accident

Even though 渋滞する is a verb-like expression, in English it often sounds more natural to translate it with a noun:

• there was a traffic jam or
• traffic was congested or
• traffic was backed up

The sentence has an explanatory, slightly emphatic feeling:

• 事故で = because of an accident
• 渋滞していて = there was traffic congestion / traffic was backed up
• 目的地まで = to the destination
• 一時間も = a whole hour
• かかった = it took
• んです = explanatory tone

So the overall nuance is something like:

Because of an accident, traffic was backed up, and it took a whole hour to get to the destination, you see.

The speaker sounds like they are explaining why the trip was so slow or why they were delayed.