Traffic authorities Thursday warned drivers to be more cautious in the coming two days as the country's hordes of tourists begin to head home at the end of the week-long National Day holiday.

Thursday saw a sudden surge of traffic flow in and out of Beijing, as people rushed home for Mid-Autumn Festival, a traditional holiday featuring family reunions taking place today. The return of residents who had gone for brief trips in the Beijing suburbs was the chief contributor to heightened traffic, said the local traffic management department.

Beijing Daily reported that nearly 300,000 vehicles poured into the city on Tuesday and Wednesday.

Clear and sunny weather this autumn added to the number of people who decided to hit the road. The temperature was 31 degrees Celsius on Wednesday, a record high for this time of year in Beijing.

A huge traffic jam is expected on the city's main roads from 4 to 6 pm today. Traffic officials have urged residents to avoid rush hour and ride public transportation to alleviate congestion.

Long lines of vehicles were seen inching along at the entrances of Badaling, Beijing-Chengde and Beijing-Shijiazhuang highways, which lead to the suburbs of the city. Traffic volume reached saturation around the city's major places of interests such as the Summer Palace, the Fragrant Hills, and the Forbidden City.

Besides the huge traffic flow, weather conditions in parts of the country also posed danger for traffic safety. Heavy fog continued to shroud Northeast China's Liaoning Province yesterday since it hit most parts of the province on Wednesday.

The low visibility caused a collision of two repair vehicles on the railway near Huanggutun Railway Station, injuring 30 workers.

According to local traffic control authorities, sections of four expressways in the province, including the expressway connecting Beijing and Shenyang, the provincial capital, were forced to shut down for a few hours from 9:00 am yesterday.

Early yesterday morning, the local meteorological observatory gave a warning of heavy fog for the Huludao area along the Beijing-Shenyang expressway, forecasting that visibility would be down to less than 200 metres in the area.