Data visualization
First, charts were made to better understand the difference frequencies of total accidents across the variables we aim to measure. The variables looked at are the time of day, the day of the week, the month, the year, and the road types all across the years 2007 to 2017.
Figure 1. Frequency of traffic accidents by time of day in Toronto, Canada between 2007 to 2017
Looking at the frequencies of accidents by the time of day shows that traffic accidents have the lowest frequency at 4am (04:00) and then start to increase in frequency until peaking at 6pm (18:00) and then decreasing. The increase and decline in the number of frequencies from the low points to the high point is pretty even and if the x axis was changed to start at hour 04:00 the curve of the frequencies would be normally distributed.
Figure 2. Frequency of traffic accidents by time of day in Toronto, Canada between 2007 to 2017
The number of accidents by the day of the week shows consistent numbers with only friday as an outlier having a higher number of accidents than the rest. The weekdays aside from friday all have similar frequencies at around 1700 accidents. In comparison to the weekend days, saturday and sunday have fewer accidents and they can be visually grouped separately but they still fall within the same range of the other weekdays aside from friday.
Figure 3. Frequency of traffic accidents by Month in Toronto, Canada between 2007 to 2017
The number of accidents by month show an increase in accident frequencies in the warmer months, peaking in June to October, with frequencies reducing in the colder months. This could be due to less driving in the winter months as Toronto has snowstorms and cold weather reducing the amount of drivers on the road.
Figure 4. Frequency of traffic accidents by year in Toronto, Canada between 2007 to 2017
Looking at the years, there has be an overall decrease in traffic accidents since 2007 with the exception of 2012 where frequencies increased. The first half of the timeframe from 2007 to 2011 shows a linear decrease but after the spike in 2012, there is more variability such as between 2014 to 2017 as the frequencies of accidents are less but there is no clear trajectory.
Figure 5. Frequency of traffic accidents by different major road types in Toronto, Canada between 2007 to 2017
The types of roads that accidents are most frequent on are major arterial arterial roads, which represent less than 3/4ths of the total traffic accidents. The second road type that produces traffic accidents are minor arterial roads at about 1/5th of the total amount. In comparison to the rest of the road types the arterial roads are the dominant location of traffic accidents in Toronto. This could be a result of the amounts of these types of road types compared to the others, such as how expressways are more specifically located and only at certain areas than the distribution of arterial roads.