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. Author manuscript; available in PMC: 2016 May 1.
Published in final edited form as: Comput Environ Urban Syst. 2015 May 1;51:59–69. doi: 10.1016/j.compenvurbsys.2015.01.007

Table 4.

Exposures for feedback: feedback name, exposure definition, maximum value and direction.

Feedback name Exposure definition Maximum value Direction
NetworkWalking Ratio of walking trips from the network: the ratio of walking trips among all
trips by all persons in the social network during the previous day
1 Positive
Walking2Walking Walking density along walking path: The number of walkers crossing a cell
during the day averaged across all cells along the walking route
Max walking density = 100 (this was determined
based on the outcomes of exploratory model runs)
Positive
Driving2Walking Driving along walking path Max driving density = 400 (this was determined based
on the outcomes of exploratory model runs)
Negative
Safety2Walking The mean value of safety for all cells along the walking route for the day 5 (by definition) Positive
NetworkTransit Ratio of public transit trips from the network: similar to NetworkWalking 1 Positive
Transit2Transit The mean value of the comfort indexa of all the transit stations along the
transit route during the day
1 (by definition);
Transit station capacity: 500 (this was determined
based on the outcomes of exploratory model runs)
Positive
Driving2Transit Driving along transit path: The number of driving trips crossing a cell during
the day averaged across all cells along the transit route
Max driving density = 400, see Driving2Walking Negative
NetworkDriving Ratio of driving trips from the network: similar to NetworkWalking 1 Positive
Driving2Driving Driving along driving path: The number of driving trips crossing a cell during
the day averaged across all cells along the driving route
Max driving density = 400, see Driving2Walking Negative
a

Comfort index: The model does not include actual “buses”, and we track the total number of passengers who pass through a certain transit station over a day. We define a “comfort index” ∈ (0, 1) for each transit station and assume that the comfort index is constant and at the highest value (=1) until the station is half full. When the passengers occupy the transit station at > 50% capacity, the trip becomes less comfortable. Each day, a comfort index is computed for each transit station. For a given day, the comfort index for that transit route is the mean value of the comfort index of all the transit stations along the transit route. For each transit station, the comfort index is computed as: If n < 0.5 * C, I = 1; Else I = 2 – 2 * n/C. Where n is the total number of passengers passing through the transit station over the whole day (total number of passengers, not unique passengers so that if the same person passes through the transit stop twice he will be counted twice) and C is the capacity of the station (the capacity is assumed to be 500 for all stations, this value is based on the observation from testing simulation).