BRUSSELS — European Union countries are getting ready to adopt a common traffic light system to coordinate traveling across the 27-nation bloc amid the coronavirus pandemic.

To ensure that member states do not close their borders to one another and avoid a repeat of the cacophony witnessed in March when the virus first struck, the EU commission came up with proposals that have been amended before their scheduled approval by EU nations on Tuesday.

The key measure is a common map of infections drawn up by the European Centre for Disease Prevention and Control. It will sort European regions into green, orange and red zones according to the severity of coronavirus outbreaks. Under the latest proposal, red zones should be areas where the total number of newly notified COVID-19 cases is more than 50 per 100,000 people during a 14-day period and the percentage of positive tests reaches at least 4%.

Regions with a lower positive rate but where the total number of cases is more than 150 per 100,000 will also be classified red.

In light of the very high level of infections across the continent now, most of the bloc should be classified as red or orange.