by Jazba Munir
The highways in Canada including the Trans Canada Highway (TCH) and the National Highways System (NHS), fall within provincial or territorial jurisdiction (Downs, 2004). The Greater Toronto Area (GTA) is surrounded by many of the 400 series highways. Some of the segments or between interchanges experience higher traffic volume than others (Downs, 2004). The traffic volume during certain hours such as morning rush hours (6:30 – 9:30) and evening rush hours (4:30- 6:30) results in traffic congestion. This traffic congestion is experienced on highway (Hwy) 401 that is the most “busiest” highway of North America. In 2016, City of Toronto Council approved the road tolls for Gardiner Express and Don Valley Parkway (DVP) to decrease the traffic volume and congestion on these two highways (Fraser, 2016). This proposal was not implemented; nonetheless, it can be visualized using Tableau that whether the speed improves by using the dataset to compare the toll route with non-toll route. The steps on the Tableau: The dataset used for visualization can be organized and clean using Microsoft Excel or Tableau. The speed data is retrieved in points form. For instance, each point has a x and y coordinates. The first step is to create field ID in order to connect each point (x, y) to next point (x, y); in order, to create the line of Hwy 401.The street , highways, routes layer provided by Tableau was used as a guideline to make sure that all the points are connected in a correct order (See Figure 1) .
The x and y are converted from measures to dimensions since, the x and y default setting is measures. This change can be made by dragging and dropping x and y from measures to dimensions. Another way is putting longitude into columns and latitude in to rows (See Figure 2).
The difference between the two is that dimensions are tools that are used to slice and describe data record whereas measures are values of those records that are aggregated. For further assistance please refer to: https://www.tableau.com/learn/training Once all the points appear on the map in tableau use the mark first selection to select line to connect the points (See Figure 3).
The speed data for any of the selected hwy can be placed in the colors and graduated color scheme from red to green is selected. In this color scheme red indicates minimum speed of 80km whereas green indicates maximum speed 120 km. These speeds were selected as standard to compare toll route with non-toll routes. These are some of the basics steps that are required for any spatial tableau project. The color, size, label and detail options can be selected to create the visualization much clearer (See Figure 4).
This shows the options for creating the comparison between the turbo vs snail. For further assistance please refer to: https://www.tableau.com/learn/training Once this is set up another sheet was added to include a graph component. The speeds can be organized by hour, minute, year, road (toll vs non-toll). The speed can be represented by using the color option. The speed on the map is represented with the red to green color gradient. The underneath map is layer map available through tableau (See Figure 5).
This will indicate the difference between the speed at the different part of the hwy. All the other hwy’s appear in yellow to show insects of each hwy. The sheet 1 for map and sheet 2 with a graph are combined to create a dashboard. This dash board helps to visualize the graph and map at once. The filter for each sheet is combined to make space organized more space for the sheets (See Figure 6 and 7).
For further assistance please refer to: https://www.tableau.com/learn/training The dashboard helps to know the speed and compare it based on the time and location. Based on the visualization, it can be concluded that toll routes have no congestion as the line is green. This indication is drawn based on the visualization. In contrast, the non-toll route appears red and light green for some sections. The color helps to know where the congestion occurs. Image 1:
Dashboard combining the two sheets In conclusion, the tableau visualization helps to compare between toll route vs non-toll route. Based on the dashboard, the toll route is turbo speed whereas the non-toll route are snails.
References https://www.brookings.edu/research/traffic-why-its-getting-worse-what-government-can-do/ https://www.cbc.ca/news/canada/toronto/city-council-meeting-road-tolls-1.3893884