Learn Hardcore Spanish (Spain): En mi vecindario, las farolas nuevas hacen que la calle sea menos oscura. - In my neighborhood, the new streetlights make the street less dark.

Because hacer que triggers the subjunctive when it expresses causing something to happen. The result clause is dependent on the subject’s action, so we say: Las farolas hacen que la calle sea/esté menos oscura, not …que la calle es…. Using es after hacer que is ungrammatical in standard Spanish.

Should it be esté instead of sea with oscura?

Both are possible, with a nuance:

esté suggests a state or condition (e.g., at night): temporary/resulting state.
sea suggests a general characteristic or a more permanent, descriptive change. Talking about lighting conditions, many speakers would choose esté; sea works if you mean the street is now generally less dark than it used to be.

Can I say hacen la calle menos oscura without que?

Yes. Spanish also allows hacer + direct object + adjective: Las farolas nuevas hacen la calle menos oscura or, more naturally, with a pronoun: Las farolas nuevas la hacen menos oscura. The hacer que + subjunctive version is equally common and slightly more formal.

Why not simply say iluminan or alumbran?

You can. Las farolas nuevas iluminan (o alumbran) la calle is concise and idiomatic. It states the action directly, without the causative structure or the subjunctive.

Why is the adjective after the noun in farolas nuevas? Does nuevas farolas change the meaning?

With nuevo/a, position can change nuance:

farolas nuevas = brand-new lampposts (emphasizes newness as a property).
nuevas farolas = new-to-us/additional/replacement lampposts (contrasts with previous ones). Both are correct here; choose the nuance you want.

Is vecindario the most natural word in Spain, or would barrio be better?

In Spain, barrio is more common for a city neighborhood. Vecindario is understood and correct, but it can also mean the community of neighbors. Many Spaniards would say En mi barrio… in everyday speech.

Why en mi vecindario and not por mi vecindario?

En marks location (“in/at”). Por suggests movement or distribution (“through/around”). Compare: En mi vecindario han puesto farolas (in my neighborhood) vs Por mi vecindario han puesto farolas (around/throughout my neighborhood).

Why is it oscura and not oscuro?

Agreement. Calle is feminine singular (la calle), so the adjective must be feminine singular: oscura. If the noun were masculine, you’d say oscuro.

Could I say más clara instead of menos oscura?

Yes: …hacen que la calle esté/sea más clara. Both are correct. Más clara is a positive framing; menos oscura is the negative counterpart. Choose the tone you prefer.

Is farolas the right word? What about faroles?

In Spain, a streetlight/lamppost is a farola. Farol is usually a lantern (handheld or decorative), and in idioms it means a bluff (dar un farol). For public street lighting, use farola(s).

Why is there a comma after En mi vecindario?

It’s a common stylistic comma after a fronted adverbial/prepositional phrase to aid readability. You can omit it if the phrase is short: En mi vecindario las farolas nuevas… is also acceptable.

Can I say mi calle instead of la calle?

Yes, if you specifically mean the street you live on: …hacen que mi calle esté/sea menos oscura. La calle can refer to a particular street previously known from context or “the street” in a general/local sense.

Can I replace la calle with a pronoun?

Yes: Las farolas nuevas la hacen menos oscura. Use la (not lo) because calle is feminine.

How would I say this in the past or future?

Past (completed): …las farolas nuevas hicieron que la calle estuviera/fuera menos oscura; or …la hicieron menos oscura.
Present perfect: …han hecho que la calle esté/sea menos oscura.
Future: …harán que la calle esté/sea menos oscura.

Do I need que after menos oscura to say “than before”?

You can add it for clarity: …menos oscura que antes (or …más clara que antes). Without it, the comparison is usually understood from context.

What’s the difference between oscura and a oscuras?

Oscura is an adjective describing the street: La calle está oscura. A oscuras is an adverbial phrase meaning “in the dark”: La calle está a oscuras (= there’s no light at all).