A Swedish researcher, who is working on the safety of cyclists being close passed by extra long trucks at high speeds, said that having a stipulated distance of 1.5 metres for passing cyclists is misunderstood by drivers, while also hoping to run a test where drivers perform an overtake and then get overtaken in the same way while riding a bicycle.

Dr Katja Kircher, an expert from Swedish National Road and Transport Research Institute VTI, performed a test last weekend on how experienced cyclists felt when close passed by the driver of an HGV at distances of one to two metres, at speeds of 50 and 80km/h (31 and 50mph).

Although full results of the test are yet to come out, readers of our blog were interested to know more about the study. So road.cc spoke to Dr Kircher about the project and asked what should be the safe distance for drivers to overtake cyclists at, to which she replied: “It depends.”

She said: “Having an absolute stipulated distance like just 1.5 metres can be ambiguous. It can be too little for fast traffic. It can also be impossible if you are on a narrow road. So it should be adapted to circumstances.

“1.5 metres is not enough for what we’ve done in the test — a long vehicle at high speed, especially if you don’t know that the vehicle is coming. But if it’s a wide-laned road, and there’s room for more than 1.5 metres, then it can be enough. But it depends on circumstances,” said Dr Kircher.

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In the UK, the new Higway Code came into effect last year, which outlined that drivers should “leave at least 1.5 metres (5 feet) when overtaking cyclists at speeds of up to 30mph, and give them more space when overtaking at higher speeds”.

Her test was devised in response to investigate if these very high capacity and extra-long trucks can be operated on Swedish roads which are also shared by cyclists. In the Twitter video Dr Kircher posted, she can be seen shaking her head in dismay as the truck passes her, which quite frankly would have been really scary if it were to happen on a real road.

Dr Kircher told road.cc that with the data they collected, they will be analysing things like the stability of the bicycle, both during the manoeuvre and after, as well as the aerodynamic pressure generated by the truck and how it affects the cyclist. But most of all, they are also asking the cyclists if they felt  “safe and comfortable” being passed by the truck.

However, she conceded that even though what might feel safe in the protected and regulated environment may not translate to the real world conditions. “There can be unevenness on the road, some obstacle that you have to avoid. And of course, our simulation did not factor in the cross-wind, which can really throw you off balance when a large vehicle passes you at a high speed,” she said.

“What I would say though, is that if drivers are passing cyclists like this, it should not be legal to do these manoeuvres in real traffic,” added Dr Kircher.

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The academic, who has 24 years of experience in transport and road safety research, had a policy suggestion. “In real-world scenarios, drivers should be switching lanes so that cyclists have more time and space to prepare themselves. And on narrow roads, going over to the other edge and slowing down can be an option,” she said.

According to her, something like this would be clearer to understand and easier to enforce than the ambiguous 1.5 metres, especially when so many drivers end up misinterpreting the rule.

She said: “It usually gets misunderstood as the target distance, when it should be the minimum distance. So it’s problematic to have a value like that.”

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Dr Kircher also said that she hoped to run an experiment in the future where drivers would first pass the cyclists, and then get on the bicycles and be passed by a driver in the same way that they originally passed the cyclist (in a safe and protected environment), so that drivers can have the experience and perspective of the other side and see for themselves if they felt safe and comfortable.

“What we see is people who drive but also cycle pay more attention when overtaking cyclists. There is the benefit of using the other transport mode but it would require some research,” she said. “I think it’s good if people use the bike and gain some understanding, especially if you operate a vehicle with a potential to kill.”

“One important experience of being a cyclist is that you cannot really choose a lot of what is happening. You are only on the receiving end and you’re the one who’s going to bear the brunt if there’s an impact.”