El viaje en coche se me hace más corto cuando voy con mi familia.

En coche is the normal way to say by car / in the car in Spanish.

• viajar en coche = to travel by car
• ir en tren = to go by train
• venir en avión = to come by plane

Using por coche would sound wrong here, and con coche usually means with a car in the sense of possessing or having one available, not the means of transport.

So El viaje en coche means the car journey or the trip by car.

Here, se me hace más corto means something like:

• it feels shorter to me
• it seems shorter to me
• it goes by more quickly for me

This is a very natural Spanish way to talk about a personal impression.

So the sentence is not really saying the trip is objectively shorter. It means that, from the speaker’s point of view, the trip feels shorter when they travel with their family.

This is one of the parts learners often find confusing.

In hacerse here, the se is part of the verb expression. The structure is:

hacérsele algo a alguien = something seems/feels a certain way to someone

So in:

El viaje en coche se me hace más corto

• el viaje = the thing being experienced
• se hace = becomes / feels / seems
• me = to me

The me tells you who has the impression: to me.

You do not translate this word-for-word into English. A literal version like the trip makes itself to me shorter would be nonsense in English, even though the Spanish is perfectly natural.

Because corto can describe perceived duration, not just physical length.

In English we also do something similar:

• The trip feels shorter
• The day seems shorter
• Time goes faster

So más corto here refers to how long the trip feels, not to the actual number of kilometres or minutes.

Because this sentence expresses a habitual or general truth:

cuando voy con mi familia = when I go with my family

It means whenever I go with my family, not just one specific occasion.

Spanish often uses the present tense this way for repeated situations:

• Cuando estudio, aprendo mucho.
• Cuando llueve, me quedo en casa.

So voy is the normal tense here.

Because Spanish usually omits subject pronouns when they are not needed.

The verb voy already tells you the subject is I, so yo is unnecessary unless the speaker wants emphasis or contrast.

Compare:

• cuando voy con mi familia = normal, neutral
• cuando yo voy con mi familia = more emphatic, maybe contrasting with someone else

Spanish is much more comfortable than English with leaving out subject pronouns.

It can often mean a general experience, depending on context.

Here, even though it literally says the trip by car, Spanish often uses the singular definite article in a general sense:

• El café me quita el sueño. = Coffee keeps me awake.
• La música me relaja. = Music relaxes me.

So El viaje en coche se me hace más corto... can mean something like:

• Car journeys feel shorter to me...
• The car trip feels shorter...

Context decides whether the speaker means one specific trip or the general experience of travelling by car.

Because mi familia means my family, which is the natural choice when talking about your own relatives.

Con la familia can exist, but it usually sounds more general or context-dependent, like with the family already mentioned in conversation.

Here, con mi familia is the clearest and most natural way to say with my family.

Yes, but the nuance changes.

• El viaje en coche me parece más corto... = The car trip seems shorter to me...
• El viaje en coche se me hace más corto... = The car trip feels shorter to me...

Both are possible, but se me hace often sounds a bit more experiential and subjective, as if you are talking about how the trip passes for you.

So se me hace is especially natural when talking about time, effort, distance, or difficulty as personally perceived.

Because this sentence describes a regular, real situation, not a future or uncertain one.

• cuando voy con mi familia = when I go with my family / whenever I go with my family
• cuando vaya con mi familia = when I go with my family in the future / the next time I go with my family

So the present indicative voy fits a habitual fact, while the subjunctive vaya would point to a future or not-yet-realised event.

Yes, coche is the normal word for car in Spain.

In many Latin American countries, people are more likely to say:

• carro
• auto

Since the sentence is in Spanish from Spain, coche is exactly what you would expect.

Yes. Even if the meaning is the same, there are several natural English versions:

• The car journey feels shorter when I go with my family.
• The trip by car seems shorter when I travel with my family.
• Car trips feel shorter when I’m with my family.
• The drive feels shorter when I’m with my family.

The best translation depends on context, but all of these capture the idea that the trip feels quicker or less long.