Cada vez que um peão aparece entre os carros, eu deixo de acelerar.

Cada vez que means every time that or whenever.

It introduces something that happens repeatedly:

• Cada vez que chove, fico em casa. = Every time it rains, I stay home.
• Cada vez que ele liga, ela sorri. = Whenever he calls, she smiles.

In your sentence, it shows a habitual reaction: whenever this situation happens, the speaker reacts in the same way.

Yes, peão can mean pawn in chess, but in European Portuguese it also commonly means pedestrian, especially in road and traffic contexts.

So in this sentence, um peão clearly means a pedestrian.

This is a useful word to remember for Portugal. A learner who knows Brazilian Portuguese may expect pedestre more often, but in Portugal peão is very normal in this context.

Um peão means a pedestrian: any pedestrian who appears.

The speaker is not talking about one specific, already identified person. The meaning is general:

• um peão = a pedestrian, any pedestrian
• o peão = the pedestrian, a specific one already known from the context

Because the sentence describes a repeated situation in general, the indefinite article um is the natural choice.

Literally, entre os carros means between the cars.

In natural English, depending on the situation, it could also be understood as among the cars. In a traffic context, it suggests that the pedestrian appears in the space where the cars are, possibly stepping out from between parked or moving cars.

So:

• entre = between / among
• os carros = the cars

The present tense is used here to describe a habitual action or general rule.

The sentence does not mean only one specific event happening right now. It means something like:

Whenever this happens, I do this.

That is why Portuguese uses the present tense:

• um peão aparece = a pedestrian appears
• eu deixo de acelerar = I stop accelerating

This is very common in both Portuguese and English when talking about routines, habits, or repeated reactions.

Deixar de + infinitive means to stop doing something or to cease doing something.

So:

• deixo de acelerar = I stop accelerating

In a driving context, this often means the speaker is no longer increasing speed, and may be easing off the accelerator.

Other examples:

• Deixei de fumar. = I stopped smoking.
• Ela deixou de estudar. = She stopped studying.

They are very close, and in many situations both are possible.

• deixar de acelerar = to stop accelerating / to cease accelerating
• parar de acelerar = to stop accelerating

In this sentence, deixar de acelerar sounds very natural and slightly more like I no longer continue accelerating. In a driving context, it can suggest that the speaker stops pressing for more speed.

Parar de acelerar is also understandable and natural, but deixar de acelerar fits well with a more general or descriptive style.

That is true: Portuguese often omits subject pronouns because the verb ending already shows the person.

So this sentence could also be:

Cada vez que um peão aparece entre os carros, deixo de acelerar.

Both versions are correct.

Including eu can add:

• a little emphasis
• extra clarity
• a slightly more explicit rhythm in the sentence

So eu is not necessary here, but it is perfectly acceptable.

Because the subject is singular:

• um peão = one pedestrian

So the verb must also be singular:

• um peão aparece

If the subject were plural, the verb would change:

• Cada vez que peões aparecem entre os carros...
• Cada vez que uns peões aparecem entre os carros...

So aparece agrees with um peão.

In this context, it means both at once, in a practical driving sense.

Literally, acelerar is to accelerate. But when talking about driving, it often also implies pressing the accelerator or speeding up the car.

So deixo de acelerar can be understood naturally as:

• I stop accelerating
• I ease off the accelerator
• I stop speeding up

The exact English wording depends on context, but the Portuguese is very natural.

Yes, often you can.

• Cada vez que um peão aparece..., eu deixo de acelerar.
• Sempre que um peão aparece..., eu deixo de acelerar.

Both mean something like whenever / every time.

The difference is very small here:

• cada vez que emphasizes each individual occurrence a bit more
• sempre que means whenever / whenever it happens, and can sound slightly more general

In this sentence, both are natural.

The first part, Cada vez que um peão aparece entre os carros, is a subordinate clause. The second part, eu deixo de acelerar, is the main clause.

When the subordinate clause comes first, Portuguese commonly uses a comma before the main clause:

Cada vez que um peão aparece entre os carros, eu deixo de acelerar.

This is very similar to English:

Every time a pedestrian appears between the cars, I stop accelerating.

So the comma helps separate the two parts clearly.