Smiling pedestrians: the other side of the coin

Post by Dr. Paulo Rui Anciaes

In the previous post my colleague Jemima talked about a research experiment that showed that drivers are more likely to stop at crossings when pedestrians smile at them. Some days later I came across another paper showing that drivers are also more likely to stop for a smiling hitch-hiker. There are significant gender issues reported in both of these studies, but the common result is that if the person at the side of the road is friendly, drivers will also be friendly.

But there is another side of the coin: do pedestrians feel like smiling at all when they are waiting by the side of the road? How many people are smiling in the picture below?


Pedestrian crossing in Akihabara, Tokyo. Source: Scion Cho CC BY-NC 2.0

A recent experiment in Japan (no relation with the picture above) has shown that people are more likely to smile when they are in streets with better pedestrian environment. The meaning of good pedestrian environment in this study is simple: no cars.

The experiment is described in a recent paper (Kojima 2015) and was presented as a poster in the meeting of the Transportation Research Board in Washington DC in January this year. The main author is Aya Kojima from Saitama University.

The authors set up a video survey to record pedestrians on a busy road on a normal day and on one of the days of the year when the road is car-free. They then used a program called Smile Scan to evaluate the facial expressions of 100 pedestrians in each of the days. The images for each pedestrian were processed for 10 seconds and the average and the maximum “smile level” during those 10 seconds was recorded.


Pedestrians’ smiling levels. Source: Kojima et al. (2015), p.497.

The average of each person’s maximum smile level was 19.6% in the normal day and 35% in the car-free day. The average of the average smile levels was 7.6% in the normal day and 19.8% in the car-free day. So pedestrians seem to be happier when there are no cars around them.

But that’s not all. The authors also looked at differences in pedestrian behaviour on the normal day and on the car-free day, and found that on car-free days:

  • there is a much higher proportion of 2, 3 and 4-person groups in which all members walked abreast
  • 56% of adults neither held their child’s in their arms or by the hand – but only 30% in the normal day
  • 17% brought a baby buggy but their children walked – but only 9% on a normal day
  • 67% stopped and took a picture – but 0% on a normal day
  • 28% of couples held hands – but only 21% on a normal day.

Surely these results also depend on differences in the sample of people observed on each day. So to isolate from this factor, the authors made another experiment, comparing the behaviour of the same individuals in the same busy road on the normal day and on another nearby road with much lower traffic levels. The sample is small but it is still revealing that 4 of the 14 couples that didn’t hold hands in the busy road then held hands in the quiet road.

And there’s more. The authors also assessed stress levels of five pedestrians walking on the busy road taking the same route and using the same pedestrian crossing on the normal day and the car-free day. The stress level was measured by the “skin potential level” (SPL), an indicator of emotion-related sweating. The SPL was lower for 4 of the 5 pedestrians on the car-free day. In one case, the SPL was 60% on the normal day and 35% on the car-free day. The analysis of the time-series SPL data for each individual also shows that stress increases every time a truck passed the subject.

This is a fascinating study, and it is no wonder that it won a prize for the best conference paper in one of the latest EAST (Eastern Asia Society for Transportation Studies) conferences.

This study adds to the large amount of evidence that large motorised traffic levels have a negative impact on people’s wellbeing and quality of life.

Just a detail: the road analysed in this study has an average hourly traffic level of “only” 721 vehicles per hour – but pedestrians are still much less happy than when there are no vehicles at all. So how sad must pedestrians feel in London’s Euston Road, with its 3,000 vehicles per hour.


Euston Road, London. Source: David Holt CC BY-SA 2.0

The methods used in the Saitama study are also promising. The study showed that smiling levels, and stress levels can be used as indicators of the quality of the pedestrian environment, as felt by the people experiencing that environment.

This is also an interesting application of the Smile Scan software, which until now had been mostly used in the transport industry to make sure railway employees wear the “correct” smile every morning.


Kojima, A., Fudamoto, T., Okuma, M., Kubota, H. (2015) Smile and behavior: new evaluation method for pedestrian environment. Asian Transport Studies 3 (4), 487-499. Available open access from



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