T1 – Design Safe and Efficient Public Transit System in Response to COVID-19

In order to see the current condition of Marlborough station, a base model was made as shown in the above overview figures as a control on the simulations. The purpose of the base model was to depict Marlborough station in its current form, and to establish a common “datum” to base our modifications on. The base model was later manipulated to implement five of the main designs, which were widening of the paths, split/barrier widened paths, escalator only, and split path/barrier plus escalator designs. Three different scenarios were tested with variations in pedestrian flows as a result of changes to the passenger volumes, train and bus headways as well as delays to the bus and train arrivals. These scenarios were named as the COVID or current scenario, expected or future scenario, and the worst case scenario.. The COVID case values are based on the current number of passengers passing through the station as well as currently available bus and train headways and average delay times. The expected cases are based on passenger volume  expected after the pandemic based on analysis of stakeholder feedback as well as the bus and train headways of the pre-COVID transit system. Finally a worst case scenario was made, with variables changed based on a maximum passenger demand from pre-COVID during a peak hour period and minimum train and bus headways and delays. The results from these models were used in the cost benefit and impact analysis to determine the efficacy of the simulated designs. Each design was tested in both the future and worst case scenario with the base case also being tested in the current COVID scenario as well.

This design implementation involved the widening of the pedestrian bridges in comparison to the base model. The total width of the overpass pedestrian bridges have been widened in this design from 2.2m to 3.2m. The remaining parts of the simulation are identical to the base mode, with only the overpass pedestrian bridges being widened. The purpose of implementing this design was to observe the effects of widening the pedestrian overpass bridge on pedestrian density and travel time of pedestrians within the network through comparisons in the data outputs.

With this model the path remains widened similarly to the second design implementation, but with a slight change in the paths of the pedestrians as a result of splitting some walk paths and ramps in half acting as barriers to prevent pedestrian cross interaction. Notice how this design is just a more complicated simulation than design 2, as the only difference was the introduction of splitting in the overpass bridge. 

The above figure shows the connecting overpassing having been split into two separate paths, which helps segregate the directionality of the flows from and to the platform. Pedestrians going to the station will stay on one half of the path, while pedestrians leaving the station will stay on the opposite side. The total width of the overpass pedestrian bridges have also been widened in this design from 2.2m to 3.2m. Other splits will be done in the next few designs in the simulation like those involving the stairs inside the interior platform building. The other parts of this model are identical to the base model, except for a few partial routes which had to be added in due to the splitting of the path.

This simulated model builds on the base model with changes to the ramps/stairway connecting the station platform with the rest of the network. In this design half of the stairs were taken out and replaced with a second escalator.

The above figure shows the split in the paths, with passengers coming from the train going up the escalators, while passengers going to board the trains are going down the stairs. The elevator still serves both directions of travel like the previous models, and is unaffected by the changes in this model. By effectively splitting and adding another escalator, we have added more partial routes to the simulation model, as there are now more possible routes for commuters to travel on.

Another change in this model is to the layout of the platform of the station. In this design, the waiting areas on the platform have been combined together and are no longer divided. Another change is seen in the purple objects within the waiting areas, which represent the effect of obstacles on the platform. These obstacles can be trash cans, waiting booths, ticket machines, and lamp posts found on a station platform.

This model builds on the fourth design iteration by adding another previously used design element in the split paths/barriers to the pedestrian overpass. This model is essentially an agglomeration of the previous changes all into a single model. The purpose of this design implementation was to determine if combining various design concepts would result in a significant change in passenger density and travel time. It is also useful as a good means of comparing the efficacy of certain individual design elements on the network as well as seeing if there are any externalities that cause certain design elements to countermand one another.

The above figure shows the general overview of design 5, which includes all the modelled changes that were done in Vissim. Other aspects of design like decals and signage are unable to be modeled within the Vissim simulation. Therefore, alternative visual representations have been created with Sketchup, which is a visualization/ drawing program that we used in our Fall report for the creation of 3D models like trees, and vending/ticketing machines.