La tarifa diaria incluye la asistencia en carretera.

Because tarifa is a feminine singular noun in Spanish, so both the article and the adjective must agree with it:

• la = feminine singular article
• tarifa = feminine singular noun
• diaria = feminine singular adjective

That is why you get la tarifa diaria.

A good pattern to notice is:

• el precio diario
• la tarifa diaria

Even if a noun ends in -a, you still need to learn its gender, but in this case tarifa is indeed feminine.

In Spanish, most descriptive adjectives usually come after the noun. So:

• tarifa diaria = daily rate
• literally: rate daily

This is very normal in Spanish. English often puts the adjective before the noun, but Spanish usually puts it after.

Other examples:

• seguro completo = full insurance
• costo total = total cost
• asistencia médica = medical assistance

Because the subject is la tarifa diaria, which is singular.

So the verb must also be singular:

• la tarifa diaria incluye = the daily rate includes
• las tarifas diarias incluyen = the daily rates include

The verb incluir changes depending on the subject:

• yo incluyo
• tú incluyes
• él/ella/usted incluye
• ellos/ellas/ustedes incluyen

Here, the subject is one rate, so incluye is correct.

They are similar, but not always identical.

• precio = price
• tarifa = rate, fee, fare, or charged amount according to a system

In this sentence, tarifa sounds very natural because a daily rental charge is usually thought of as a rate, not just a general price.

For example:

• precio del carro = price of the car
• tarifa diaria = daily rate
• tarifa mensual = monthly rate
• tarifa de taxi = taxi fare/rate

So tarifa is the better choice here.

Here, asistencia means assistance/help/service, specifically roadside assistance.

It is feminine, so it takes la:

• la asistencia

Be careful: asistencia does not always mean the same thing in every context. It can mean:

• assistance/help
• attendance in some situations

But in this sentence, because of en carretera, it clearly means assistance.

So:

• la asistencia en carretera = roadside assistance

Because en carretera is a very common general expression meaning on the road or roadside.

It refers to the type of assistance, not to one specific road. So it is understood as a general service:

• asistencia en carretera = roadside assistance

If you said en la carretera, it would sound more like you are talking about a specific road or a specific situation happening on the road.

Compare:

• Ofrecen asistencia en carretera. = They offer roadside assistance.
• El auto se quedó varado en la carretera. = The car got stranded on the road.

So in service descriptions, en carretera is the more natural phrase.

No. It is correct and understandable, but there are other common regional alternatives.

Depending on the country, you may also hear:

• auxilio vial
• asistencia vial
• servicio de grúa (tow service, more specific)
• asistencia en el camino (less standard, but understandable)

Still, asistencia en carretera is clear and natural, especially in formal or international Spanish.

So if you use this sentence, people will understand you well.

Not naturally. A very literal translation would sound odd in English.

More natural English is:

• The daily rate includes roadside assistance.

Why?

• tarifa usually corresponds to rate/fare/fee, not usually tariff in everyday English
• asistencia en carretera is best translated as roadside assistance, not word-for-word

This is a good reminder that Spanish and English often match in meaning, but not in the most natural wording.

Yes, that would be understandable and correct.

Compare:

• La tarifa diaria... = the daily rate...
• La tarifa por día... = the per-day rate...

Both work, but tarifa diaria sounds more compact and more natural in many business, travel, or rental contexts.

So:

• La tarifa diaria incluye la asistencia en carretera. = very natural
• La tarifa por día incluye la asistencia en carretera. = also correct, slightly more explicit

Yes, you could say incluye asistencia en carretera, and it would still sound natural.

Both are possible:

• incluye la asistencia en carretera
• incluye asistencia en carretera

The version with la sounds a bit more like you are referring to that service as a defined included feature. The version without the article sounds a little more general.

In advertising, contracts, and service descriptions, both styles appear.

So:

• with article = slightly more specific/defined
• without article = slightly more general/list-like

Neither is wrong here.

A simple pronunciation guide is:

• ca-rre-TE-ra

Important points:

• the rr is a strong rolled/trilled r
• the stress is on te
• every vowel is pronounced clearly

A rough English-friendly guide is:

• kah-rreh-TEH-rah

But the most important feature is the rolled rr in carretera. That sound is stronger than the single r in words like caro.

It is neutral and very natural. It works well in:

• rental agreements
• hotel or travel information
• websites
• customer service
• brochures

It sounds slightly more formal/informational than casual conversation, but it is absolutely normal everyday Spanish in a business or service context.

So this is a useful real-world sentence to learn.