Belgian-Dutch Study: Why you should walk/run/bike 30 to 60 feet away from each other

In a simulation of breathing particles during physical activity without facemasks, it appears one has to be as far as 30 to 60 feet to prevent viral contagions.

In a lot of countries walking, biking and jogging are welcome activities in these times of self-isolation. However, it is important to note that you need to avoid each other's particle stream when doing these activities. This comes out of the result of a study by the KU Leuven (Belgium) and TU Eindhoven (Netherlands). 

The typical social distancing rule which many countries apply between 3 to 6 feet seems effective when you are standing still inside or even outside with low wind.

When someone during a run breathes, sneezes or coughs, those particles stay behind in the air. The person running behind you in the so-called slip-stream goes through this cloud of droplets.  

Out of the simulations, it appears that social distancing plays less of a role for 2 people in a low wind environment when running/walking next to each other. The droplets land behind the duo.

When you are positioned diagonally behind each other the risk is also smaller to catch the droplets of the lead runner.

The risk of contamination is the biggest when people are just behind each other, in each other’s slipstream.

Based on these results, the scientists advise that for walking the distance of people moving in the same direction in 1 line should be at least 12–15 meters, for running and slow biking it should be 30 feet and for hard biking at least 60 feet.

Sources:

(1): https://www.demorgen.be/nieuws/belgisch-onderzoek-fietsen-joggen-of-wandelen-doe-je-best-niet-achter-elkaar-in-tijden-van-corona~b60aece6/

(2): https://www.hln.be/wetenschap-planeet/wetenschap/belgisch-onderzoek-fietsen-joggen-of-wandelen-doe-je-best-niet-achter-elkaar-in-tijden-van-corona~a60aece6/

(3): http://www.urbanphysics.net/Social%20Distancing%20v20_White_Paper.pdf

(4) https://medium.com/@jurgenthoelen/belgian-dutch-study-why-in-times-of-covid-19-you-can-not-walk-run-bike-close-to-each-other-a5df19c77d08