bié zài zìxíngchēdào nìxíng.

别 is used to make a negative command, so it means don’t.

In this sentence, 别 tells someone not to do the action that follows:

• 别逆行 = Don’t go the wrong way / Don’t travel against traffic

It is very common in spoken Chinese and in warnings or signs.

不 usually negates statements, not commands.

• 我不去 = I’m not going
• 他不懂 = He doesn’t understand

But if you want to tell someone not to do something, Chinese usually uses:

• 别
• or 不要

So:

• 别在自行车道逆行 = natural negative command
• 不在自行车道逆行 would sound like a statement, not a warning

Yes, very often 别 can be understood as a shorter, more direct form of 不要 in commands.

Compare:

• 别在自行车道逆行。
• 不要在自行车道逆行。

Both are correct.
别 is shorter and very common in everyday speech and on signs.
不要 can sound a little fuller or slightly more formal/emphatic, depending on context.

Here 在 is a preposition meaning at / in / on a location.

So:

• 在自行车道 = in/on the bicycle lane

It tells you where the action happens.

The structure is:

• 别 + 在 + place + verb

So:

• 别在自行车道逆行
  literally: Don’t, in the bicycle lane, go against traffic

In natural English, we would reorder that more smoothly.

自行车道 means bicycle lane or bike lane.

It is made up of:

• 自行车 = bicycle
• 道 = lane / الطريق-like path or route in this context

So literally:

• 自行车道 = bicycle lane

This is a very common road-related compound word.

逆行 means to go against the proper direction of traffic, or more literally, to travel in the opposite direction.

• 逆 = opposite / against
• 行 = move / go / travel

In traffic language, 逆行 is used for going the wrong way on a road, lane, or street.

So it is more specific than just go backwards. It means moving against the allowed flow of traffic.

Chinese often leaves out the subject when it is obvious.

In a warning, instruction, or sign, the listener/reader is understood automatically:

• 别在自行车道逆行。 really means something like
• 你别在自行车道逆行。

But adding 你 is usually unnecessary, especially on signs. Chinese often prefers short, efficient wording in public notices.

Because 逆行 itself already works as the main action here.

You might expect something like:

• 别在自行车道骑车逆行

But on signs and in traffic language, Chinese often uses a more compact style.
Since the context is already a bicycle lane, 逆行 alone is enough.

So the sentence is concise but fully natural for a warning sign.

Usually, the most natural order is:

• 别 + 在 + place + verb

So:

• 别在自行车道逆行 is the normal phrasing.

You may sometimes hear different word orders in speech for emphasis, but for a standard warning or sign, this version is the most natural and standard.

In meaning, it functions as one compound noun: bicycle lane.

It is built from smaller parts:

• 自行车 = bicycle
• 道 = lane

But learners should generally understand and remember 自行车道 as a fixed vocabulary item.

It sounds very natural as a public sign, warning, or traffic instruction.

Chinese signs often use:

• short wording
• omitted subjects
• compact verbs
• direct commands

So 别在自行车道逆行 sounds like something you might see on a street sign, community notice, or safety poster.

In everyday speech, a person might also say it, especially if warning someone directly.

A helpful pattern is:

• 别 + 在 + location + action

Applied here:

• 别 = don’t
• 在自行车道 = in/on the bicycle lane
• 逆行 = go against traffic

So the sentence is built very logically:

1. command marker
2. place
3. action not allowed

This is a useful pattern you can reuse:

• 别在这儿抽烟。 = Don’t smoke here.
• 别在马路上玩。 = Don’t play on the road.
• 别在图书馆说话太大声。 = Don’t speak too loudly in the library.

In 逆行, 行 is pronounced xíng.

So:

• 逆行 = nìxíng

This is different from some other words where 行 has a different pronunciation, for example:

• 银行 = yínháng

So yes, 行 is a character with multiple pronunciations, and here it is xíng.

No. 逆行 can be used for many kinds of traffic participants, especially vehicles.

For example, it can describe:

• bicycles
• electric bikes
• motorcycles
• cars

It means the person or vehicle is moving against the designated traffic direction. In this sentence, because the location is 自行车道, the most relevant image is someone riding in the bike lane the wrong way.