Officers were tracking cars along several points on a given stretch of road to check if their average speed exceeded the permissible limit.
Police were expected to pay special attention to sites where accidents due to excessive speed occur most often, state news agency PAP reported.
The police campaign runs until 10pm.
Poland’s prime minister said last year his government would launch a major drive to improve road safety.
“A comprehensive plan to radically improve road safety will be one of the government's priorities in its new term in office," Prime Minister Mateusz Morawiecki announced at the time.
In 2017, around 2,800 people died and 11,000 were severely injured in road accidents in Poland, putting the country close to the bottom of a European Union ranking on road safety.
(pk)
Source: PAP