Si vas en moto, es importante que respetes a los peatones y que lleves casco.

Because in this sentence si means if, and for real or likely conditions in the present, Spanish normally uses the present indicative, not the subjunctive:

• Si vas en moto... = If you ride/go by motorbike...

So vas is correct because it is the present indicative of ir.

You would not normally say Si vayas... here.

A useful contrast:

• Si vas en moto, lleva casco. = If you ride a motorbike, wear a helmet.
• Quiero que vayas en moto. = I want you to go by motorbike.
  Here vayas is subjunctive because it comes after a verb of wanting.

Because the structure es importante que... triggers the subjunctive.

Spanish often uses the subjunctive after expressions of:

• importance
• necessity
• emotion
• doubt
• recommendation

So:

• Es importante que respetes...
• Es importante que lleves...

Both respetes and lleves are present subjunctive forms.

This is very natural in Spanish, even though English usually just says:

• It’s important that you respect...
• It’s important that you wear...

Both are second person singular subjunctive forms, so they mean you when speaking informally to one person (tú).

• respetes = that you respect
• lleves = that you wear/carry

The subject tú is not written because Spanish often leaves subject pronouns out when the verb form already makes it clear.

So the full version would be:

• Es importante que tú respetes a los peatones y que tú lleves casco.

But that sounds unnecessary unless you want emphasis.

Because there are two coordinated subjunctive clauses:

• que respetes a los peatones
• y que lleves casco

Repeating que is very common and natural in Spanish. It helps clearly mark both verbs as part of the structure triggered by es importante.

You may sometimes hear people omit the second que in some contexts, but here repeating it sounds clear and standard:

• Es importante que respetes... y que lleves...

Ir en moto means to go by motorbike / to ride a motorbike.

In Spanish, ir en + vehicle is a very common way to say how someone travels:

• ir en coche = go by car
• ir en tren = go by train
• ir en autobús = go by bus
• ir en moto = go by motorbike

So Si vas en moto is naturally understood as:

• If you’re riding a motorbike or
• If you go by motorbike

This is the personal a, which Spanish often uses before a specific human direct object.

Here, los peatones refers to people, so Spanish says:

• respetar a los peatones = to respect pedestrians

Compare:

• Respeto a mis vecinos. = I respect my neighbours.
• Respeto las normas. = I respect the rules.

The a is not translated into English here; it is just a normal Spanish grammar feature.

Because the two nouns are being used in different ways.

a los peatones

Here we mean a group of people in general but as a class:

• the pedestrians So the definite article los is natural.

lleves casco

Here Spanish often leaves out the article when talking about wearing or using something in a general sense:

• llevar casco = to wear a helmet
• llevar cinturón = to wear a seat belt

English often says a helmet, but Spanish commonly says just casco in this kind of general statement.

You could also hear:

• lleves un casco but lleves casco sounds more general and idiomatic in a safety message.

Yes, llevar can mean both to carry and to wear, depending on context.

In this sentence:

• llevar casco = to wear a helmet

Other examples:

• Lleva una mochila. = He/She is carrying a backpack.
• Lleva gafas. = He/She wears glasses.
• Lleva abrigo. = He/She is wearing a coat.

So here the context makes it clear that lleves casco means wear a helmet, not carry a helmet.

Yes, respetar literally means to respect, and in traffic or safety contexts it often means:

• to respect
• to observe
• to be considerate toward
• to comply with

So respetar a los peatones means treating pedestrians properly and giving them the priority or consideration they deserve.

In road-safety language, this is very natural Spanish.

Moto is very widely used in Spain and across much of the Spanish-speaking world as a common short form for motocicleta.

In Spain, moto is extremely common in everyday speech.

So:

• ir en moto is normal and natural
• ir en motocicleta is correct too, but more formal or less everyday

Yes, but the tone changes.

• Es importante que respetes a los peatones y que lleves casco.
  = It’s important that you respect pedestrians and wear a helmet.

This sounds like advice, recommendation, or general guidance.

• Debes respetar a los peatones y llevar casco.
  = You must / should respect pedestrians and wear a helmet.

This sounds more direct and stronger.

So both are possible, but es importante que... is a little less blunt and uses the subjunctive.

Yes, but the nuance is slightly different.

• Si vas en moto = If you go / travel by motorbike; if you’re on a motorbike
• Si conduces una moto = If you drive/ride a motorbike

Si vas en moto is broader and very natural in general advice. Si conduces una moto focuses more specifically on operating the vehicle.

In this sentence, Si vas en moto sounds very idiomatic and natural.

They are both present subjunctive forms.

From respetar

• infinitive: respetar
• yo form in present indicative: respeto
• remove -o and add subjunctive endings for -ar verbs:
  • respete, respetes, respete, respetemos, respetéis, respeten

So here:

• respetes = you (tú) respect

From llevar

• infinitive: llevar
• yo form: llevo
• subjunctive pattern:
  • lleve, lleves, lleve, llevemos, llevéis, lleven

So here:

• lleves = you (tú) wear/carry

This is the normal way regular present subjunctive forms are built.