BEIJING, Jan 14 (Reuters) - Aiming to reduce road traffic and pollution during the Winter Olympics, host city Beijing announced a series of measures on Friday, including a ban on heavy vehicles transporting construction waste, dirt, sand and gravel for nearly two months. In response to any forecast increase in air pollution levels, which often happens during the winter months, authorities will ban all medium- and heavy-duty fuel trucks from the road and use of government vehicles will be cut by 80 percent. The controls will be implemented for 55 days, starting on Jan. 21, a city government notice said. The Winter Olympics will run from Feb 4 to Feb 20, to be followed by the Paralympics. Due to COVID-19, the games will take place in a "closed loop" at venues in Beijing and neighbouring Hebei province, and there are no international spectators allowed. Beijing has also designated roads that will only be open to vehicles providing services for the Olympics during periods from January to March. The city is also encouraging companies, especially those located near Olympic venues, to adopt flexible working schedules for employees, such as working from home and alternating working hours, state media reported Friday, citing Wu Shijiang, deputy director of Beijing Traffic Management Bureau. The public has also been encouraged to reduce use of private cars and take public transportation.