AFFECTIVE WALKABILITY

IN VIVO, AND IN VITRO EXPERIMENTS

Social inclusion of elderly pedestrians in urban contexts by enhancing healthy mobility means increasing the level of walkability, where the perception of safe walking and safe road crossing is crucial.

Measuring and recognizing the affective state of people during walking activities contribute to a better comprehension of their perception of the environment, and a better definition of walkable urban area, introducing the concept of affective walkability.

In order to access affective walkability we have designed and performed in vivo (i.e. in real life uncontrolled environments) and in vitro (i.e. in controlled laboratory environments) experiments.

The measurement of the affective states relies on physiological responses, which are uncontrolled and autonomous reactions of our nervous system, that can be considered honest indicators of our emotions.

In our experiments we collected:

Galvanic Skin Response (GSR): also known as Skin Conductance (SC), which is connected to sweating and perspiration on the skin
Photoplethysmography (PPG): that measures the blood volume registered just under the skin, which can be used to obtain the heart rate of the subject
Electromyography (EMG): which measures the muscle activity of the person by surfacsensors. In particular, activities related to the medial gastrocnemius muscle and to the anterior tibial muscle have been acquired using the same device.
Accelerometer and Gyroscope data.

IN VITRO EXPERIMENTS

The affective walkability assessment has been performed with a controlled laboratory experiment at the University of Tokyo. The acquisition of physiological signals during experimental activities requires the design of proper experimental settings and protocol.

We benefited from the valuable contribution of Architect Matteo Belfiore in designing the experimental setup and projecting what we call the "hearth path" .

During the experiment the subjects faced different walking environments.

Collision avoidance: two subjects at the same time, walk with their own pace along the heart path. At about half of the path, they reach the collision avoidance zone where they have to avoid the collisions with both the obstacles (swinging pendulum) and the other subject.
Forced speed walk: participants have to walk to a forced speed based on the metronome ticking, along the heart path. Three speeds are considered: 70 bpm , 85 bpm and 100 bpm.
Free walk. participants can walk freely without obstacles or speed constraints along the hearh path.

IN VIVO EXPERIMENTS

The in vivo experiment considers two different walking scenarios related to different perception of safety: free walking on a sidewalks, and crossing a two way road in correspondence to a zebra crossing, without traffic lights. Without becoming dangerous for the subjects who undergo the experiment, the more dangerous the crossing, the greater the emotional arousal triggered and the better the signals acquired.

We have carried out the experiment two times, considering two different populations and geographical places. In the first session we have involved 14 young adults, all computer science students at the University of Milano-Bicocca. The chosen environment contemplated an unsupervised crossroad on a two-way road, not far from the main buildings of the University of Milano-Bicocca. In the second session thanks to the collaboration of our partner AUSER, we have involved 21 elderly people, citizen of Cantù.

Cantù is a Lombard city that has about 40,000 inhabitants and is located at the foot of the Como pre-Alps. The history of Cantù is very ancient and has several narrow streets often uphill. However, this diffcult configuration of the city does not prevent heavy vehicles, buses and a large number of cars from engaging the streets of the city center, which is very busy at rush hour. All these characteristics make Cantu an ideal setting to test stressful routes or crossings for an older person.

AUTONOMOUS VEHICLE

In the LONGEVICITY project, Iralab, altogether with colleagues from the MMSPlab, explored the relationship between an autonomous vehicle and pedestrians of different age ranges, to evaluate how the vehicle could best behave in order to allow a smooth and confident crossing of the road, by the pedestrians.

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