Allez tout droit.

It is the imperative form of aller (to go).

So allez tout droit is a command or instruction: Go straight ahead.

The imperative of aller is:

• va — informal singular
• allons — let's go
• allez — formal singular or plural

In this sentence, allez is the vous imperative form.

In French, the imperative normally leaves out the subject pronoun.

So instead of:

• Vous allez tout droit — You go / are going straight ahead

you say:

• Allez tout droit — Go straight ahead

That is normal for commands in French.

Allez can be used for:

• one person formally
• more than one person

So Allez tout droit could mean:

• Go straight ahead — said politely to one person
• Go straight ahead — said to a group

If you were speaking to one friend, child, or someone you address as tu, you would usually say:

• Va tout droit

You would say:

• Va tout droit.

That is the tu imperative form of aller.

So the contrast is:

• Va tout droit. — to one person informally
• Allez tout droit. — to one person formally or to several people

Tout droit is a very common expression meaning:

• straight ahead
• straight on
• directly forward

It functions as a set phrase in directions.

Even though tout often means all or everything in other contexts, in tout droit you should learn it as one expression: straight ahead.

Examples:

• Continuez tout droit. — Continue straight ahead.
• Allez tout droit jusqu'au carrefour. — Go straight ahead until the crossroads.

Not usually in this kind of instruction.

In directions, tout droit is the normal expression for straight ahead.

By itself, droit more often means:

• right / upright / straight
• or in some contexts law / right

So for giving directions, tout droit is the phrase you want.

The form is the same, but the function is different.

• Vous allez tout droit. — You are going straight ahead / You go straight ahead
• Allez tout droit. — Go straight ahead

So:

• with vous, it is a normal statement
• without vous, it is an imperative command

French often uses the same verb form for both, so context matters.

A simple pronunciation guide is:

• Allez ≈ ah-lay
• tout ≈ too
• droit ≈ drwah

A more French-like pronunciation is:

• allez — [a.le]
• tout — [tu]
• droit — [dʁwa]

A few useful notes:

• the final -z in allez is not pronounced like English z here; the word ends with an ay sound
• the final t in tout is silent
• droit has a French r, not an English one

Yes. Allez tout droit can be used in many situations where someone should continue straight:

• walking directions
• driving directions
• cycling
• moving through a building or station

It is a general direction instruction, not limited to walking.

Yes. Continuez tout droit is also very common and often feels a bit more explicit:

• Allez tout droit — Go straight ahead
• Continuez tout droit — Continue straight ahead

Both are natural in directions.
Continuez tout droit emphasizes that the person should keep going straight.

It is neutral and perfectly normal in directions.

Because it uses allez, it already matches either:

• formal singular
• or plural

So it is not rude by itself.

If you want to sound even softer, you could add something like:

• Allez tout droit, s'il vous plaît. — Go straight ahead, please.

But in everyday direction-giving, Allez tout droit is completely natural.