Researchers are recommending that cyclists avoid slipstreaming to reduce the risk of coronavirus infection.
Aerodynamic experts from the Netherlands and Belgium have investigated how micro-droplets travel through the air during running and cycling, in the hopes of offering advice on how to stay safe during the pandemic.
The affects of slipstreaming mean that cyclists should stay at least 10 metres apart when riding, increasing the gap to 20m when riding together at speed, according to the researchers.
Bert Blocken, professor of civil engineering at Eindhoven University of Technology, said: “If someone exhales, coughs or sneezes while walking, running or cycling, most of the micro-droplets are entrained in the wake or slipstream behind the runner of cyclist.
“The other person who runs or cycles just behind the leading person in the slip then moves through that cloud of droplets.”
Professor Blocken added: “The slipstream is the zone that arises right behind a person when they are walking or cycling, and which pulls the air a bit along with this moving person, as it were.
“Cyclists like to position themselves in the slipstream of others to reduced the air resistance. But someone who walks or runs also has such a slipstream. We have seen that no matter how that zone forms, droplets end up in that air stream, so it’s best to avoid that slipstream.”
The researchers simulated the release of saliva particles from people in motion in different configurations, either side by side, diagonal from one another and directly behind.
Based on the results, the researchers recommend staying four to five metres apart when walking, 10m when running or cycling slowly, and at least 20m when cycling fast.
Professor Blocken added: “If you want to overtake someone, it is also recommended to start “pre‐ sorting” into a staggered arrangement from a fairly long distance – twenty meters with bicycles, for example, so that you can overtake carefully and at a proper distance by moving in a straight line.” Compare it to driving: if you want to overtake, you should also not wait until the very last moment.”
The group of engineers and aerodynamicists have released their findings to the public before submitting a peer-reviewed article, because they decided given the urgency of the situation it would be “unethical” to keep the results out of the public eye.