There has been some discussion in the comments lately about whether drivers display more courtesy when cyclists ride upright bicycles and dress in "regular" clothing. One reader wrote that "the uprightness [is] more visible and [the clothing] maybe less offensive to your average driver... The images generated revolve around Mary Poppins. Only a monster would do anything mean to Mary Poppins" (Christopher Fotos, December 10, 2010). Do you agree?Whenpoked fun at the Tweed Ride last week in his typically colourful manner, I related to the associations he made with colonialism and Civil War re-enactments: I never found Tweed Rides appealing for precisely those reasons. But I disagree with his conclusion that nice clothes on a bike are generally "not traffic calming." It's one thing to be dressed in what appears to be period costume, joined by dozens of others who have done the same while taking a joyride through the city. It's another thing entirely to be cycling to work in a suit and a wool overcoat, because that is what you normally wear to work.Speaking solely from my own experience, I'd noticed as soon as I started cycling for transportation that drivers are nicer to me when I dress "normally." And since having begun to ride a roadbike recreationally, the difference between how I am treated on the roads when on a bike with drop bars, wearing "sporty clothing" and my hair tucked away, in comparison to how I am treated when on an upright bike in "city clothing," with my work bag in the basket and my hair visible, is noticeable. The majority of the time, when a driver is rude to me or impatient with me, I am on my roadbike - which is odd, since I am faster on a roadbike than I am on an upright bike, and thus should be less "in the way." To me, this just confirms that drivers' perceptions of how annoying a cyclist is, are entirely subjective. You can be going 10mph and this will be okay, or you can be going 25mph and they might still be annoyed.In part, I think the idea of not wanting to harm Mary Poppins is valid - in the sense that a cyclist dressed "normally" looks more human to the driver. The way people process each other visually and emotionally is governed by a complicated system of simulation and self-recognition (this is actually my research specialty, so I've spent a lot of time thinking about it!). And from that point of view, it makes sense to speculate that the more "I am human! I amyou!" signals we give off when cycling, the more empathy a driver will feel towards us. Dehumanisation, on the other hand, makes it easier to cause harm to another human being - because we fail to simulate their emotional state and relate to their suffering. And dehumanisation is facilitated by things like uniforms (one reason it is easier to kill soldiers and war prisoners, than civilians), or anything else that obscures individuality and hides signs of humanness.But in addition to the Mary Poppins effect, I think that there are also implicit right of way rules that are present in the driver's mentality, from which "normally" dressed cyclists benefit. I am not suggesting that this is justified in any way, but I get the impression that drivers are enraged by the associations with leisure and recreation that a road cyclist's attire evokes. The cyclist is on the road because they are going for a ride. The driver, however, is on the road because they need to be somewhere. So the reasoning follows, that the person who needs to be somewhere clearly has more valid reasons to use the limited road space than the person who is going for a ride, which is why the presence of the road cyclist causes annoyance. On the other hand, when the cyclist's appearance suggests that they are also engaging in transportation and need to be somewhere just like the driver, their presence on the roads seems more justified. This is just a theory, but the fact that drivers will shout things like "Get a job!" to roadies, but will ask me "How long does it take you to get to work?" at red lights when I am dressed up, gives it some plausibility. They associate the "normal clothes" look with going to work, and they associate the sporty look with recreation.All of this is, of course, entirely speculative and none of it is to say that cyclists should strive to dress in any particular way in order to secure the driver's compassion. Only the certainty of criminal prosecution can reliably deter a driver from causing harm to a cyclist, and I hope to see that become the norm in the US in the near future. Until then, let's hope that drivers can find a way to see Mary Poppins in all of us, whether we are dressed in lycra, tweed, or something in between.