Если мы выйдем пораньше, мы не попадём в пробку у моста.

Because both verbs are perfective: выйти and попасть.

In Russian, perfective verbs do not have a true present tense. The forms that look “present-like” are actually used with future meaning:

• мы выйдем = we will leave / we will go out
• мы попадём = we will get into / we will end up in

Compare:

• выходим = we are going out / we go out (imperfective, present)
• выйдем = we will go out (perfective, future)

So this is a very normal Russian pattern.

That is a major difference between English and Russian.

In Russian, when you are talking about a real future condition, it is normal to use the future in both parts:

• Если мы выйдем пораньше, мы не попадём...

Literally, it is like:

• If we leave earlier, we will not get...

English usually avoids will in the if-clause, but Russian does not. So this sentence is completely standard.

Literally, выйти means to go out or to come out.

But in many everyday contexts, Russian uses выйти where English would often say leave:

• выйти из дома = leave the house / go out of the house
• выйти пораньше = leave a bit earlier

Russian often does not state the place you are leaving from if it is obvious from context.

Because the sentence refers to one completed action in the future: leaving earlier on a particular occasion.

Perfective is used when the action is seen as a single whole or as having a result:

• Если мы выйдем пораньше... = if we leave earlier (once, on that occasion)

If you used the imperfective, it would sound wrong or would change the meaning:

• Если мы выходим... = if we are in the habit of leaving / if we are leaving
• Если мы будем выходить... = if we will be leaving (process-focused, unusual here)

So perfective is the natural choice.

Пораньше means earlier, often with the sense of a bit earlier or somewhat earlier.

• раньше = earlier
• пораньше = a little earlier / nice and early / somewhat earlier

The по- here often softens the idea and makes it sound more natural or conversational.

So:

• выйдем раньше = we’ll leave earlier
• выйдем пораньше = we’ll leave a bit earlier

Both are possible, but пораньше is very common in speech.

It is a very common expression meaning to get stuck in traffic or to get into a traffic jam.

Literally:

• попасть = to get into / to end up in
• пробка = a jam, here a traffic jam

So:

• попасть в пробку = to get into a traffic jam

This is the standard Russian way to express that idea.

Because попасть в normally takes the accusative case: it expresses movement or entry into a situation/place.

So:

• пробка = nominative
• в пробку = accusative

This fits the idea of ending up in traffic.

Compare:

• попасть в дом = get into the house
• попасть в беду = get into trouble
• попасть в пробку = get into a traffic jam

У моста means by the bridge, near the bridge, or at the bridge.

The preposition у requires the genitive case, so:

• мост = bridge
• моста = genitive singular

So:

• у моста = near the bridge

In this sentence, it describes where the traffic jam is: the traffic jam near the bridge.

It can be left out:

• Если мы выйдем пораньше, не попадём в пробку у моста.

That is perfectly natural.

But repeating мы is also natural and often makes the sentence feel clearer or more balanced:

• Если мы выйдем пораньше, мы не попадём...

So the second мы is optional, not wrong.

Because попасть is perfective, and the future of a perfective verb is formed without буду / будем.

So:

• попадём = we will get into
• не попадём = we will not get into

The буду + infinitive future is used with imperfective verbs:

• будем попадать = we will be getting into / we will keep getting into

That would not fit this sentence well, because here we mean one specific result: we won’t get stuck.

Good question. In careful spelling, this word is:

• попадём

The ё shows both the pronunciation and the stress.

In many everyday texts, Russians omit the dots and write:

• попадем

But it is still understood as попадём, not попадаем.

For learners, it is very helpful to pay attention to ё, because it often tells you exactly where the stress is.

Yes. Russian word order is flexible.

This version is neutral and natural:

• Если мы выйдем пораньше, мы не попадём в пробку у моста.

But you could also hear:

• Если выйдем пораньше, не попадём в пробку у моста.
• Если мы пораньше выйдем, мы не попадём в пробку у моста.

The meaning stays basically the same, but the emphasis can shift slightly. The original sentence is a very standard, neutral way to say it.