3 sentences

1. 交通高峰时段路上非常拥堵。

   jiāo​tōng gāo​fēng shí​duàn lù shàng fēi​cháng yōng​dǔ.

   The roads are very congested during peak traffic hours.

   Source: Dong Chinese Dictionary

2. 由于交通拥堵，车辆行驶非常缓慢。

   yóu​yú jiāo​tōng yōng​dǔ, chē​liàng xíng​shǐ fēi​cháng huǎn​màn.

   Due to traffic congestion, the vehicles are moving very slowly.

   Source: Dong Chinese Dictionary

3. 交通警察正在引导车辆分流，以缓解市中心的拥堵。

   jiāo​tōng jǐng​chá zhèng​zài yǐn​dǎo chē​liàng fēn​liú, yǐ huǎn​jiě shì​zhōng​xīn de yōng​dǔ.

   Traffic police are diverting vehicles to ease congestion in the city center.

   Source: Dong Chinese Dictionary