هذا الطريق أسرع.

In Arabic, the present-tense is / are is usually not spoken or written in simple sentences like this.

So هذا الطريق أسرع is literally something like this road faster, but it naturally means this road is faster.

If you wanted a past meaning, Arabic would use a verb such as كان: كان هذا الطريق أسرع = This road was faster.

Because طريق is commonly treated as a masculine noun in Modern Standard Arabic, so it takes the masculine singular demonstrative هذا.

• هذا = this for masculine singular nouns
• هذه = this for feminine singular nouns

So:

• هذا الطريق = this road
• but with a feminine noun, you would say something like هذه السيارة = this car

In Modern Standard Arabic, demonstratives like هذا usually come before the noun:

• هذا الطريق = this road
• هذه المدينة = this city

That is the normal standard pattern. English also puts this before the noun, so in this sentence the order is actually quite similar.

After demonstratives in standard Arabic, the noun is normally definite, so it usually takes الـ.

So Arabic says:

• هذا الطريق not usually
• هذا طريق

This is just the normal structure of the language. You can think of هذا الطريق as one definite phrase meaning this road.

Because ط is a sun letter. When الـ comes before a sun letter, the l sound of الـ is assimilated to the next consonant.

So:

• written: الطريق
• pronounced: aṭ-ṭarīq(u)

This happens in many words, for example:

• الشمس → ash-shams
• الطالب → aṭ-ṭālib

The spelling stays the same, but the pronunciation changes.

أسرع is the comparative / superlative form, often called the elative in Arabic grammar.

From the adjective سريع (fast), Arabic forms:

• سريع = fast
• أسرع = faster or sometimes fastest, depending on context

In this sentence, أسرع is the predicate of the sentence: it tells you something about هذا الطريق.

Because the two words mean different things:

• سريع = fast
• أسرع = faster

So:

• هذا الطريق سريع = This road is fast
• هذا الطريق أسرع = This road is faster

Arabic is making the same distinction that English makes between fast and faster.

Arabic can leave the comparison understood from context, just like English sometimes can.

If you want to say faster than explicitly, you usually add من:

• هذا الطريق أسرع من ذلك الطريق
  = This road is faster than that road

So:

• أسرع = faster
• أسرع من = faster than

In this kind of comparative use, أسرع normally appears in the basic elative form without الـ.

Also, words on this pattern are typically treated as diptotes, which means that when they are indefinite, they do not take tanwīn.

So in fully vowelled Arabic, you would write:

• أسرعُ not
• أسرعٌ

This is a more advanced grammar point, but it is completely normal here.

In careful fully vowelled MSA, it would be:

هٰذا الطَّريقُ أَسرَعُ

A simpler typed version is:

هذا الطريقُ أسرعُ

Here:

• الطريقُ is nominative
• أسرعُ is also nominative, because it is the predicate of a nominal sentence

In normal unvowelled writing, these endings are usually omitted.

Not always in the way a regular adjective does.

With ordinary adjectives, Arabic usually shows full agreement:

• الطريق السريع
• السيارة السريعة

But the comparative form أسرع often stays in the masculine singular form when used as an elative, especially in simple comparative statements.

For example:

• هذه السيارة أسرع = This car is faster

So even though سيارة is feminine, أسرع can still stay in this basic form. That is normal for this comparative pattern.