Statistics of road accidents in Bangalore are a classic example of what numbers can tell depending on whether you have an ulterior motive in interpretation, or just want to look at figures dispassionately.
Contrary to the popular notion that road safety scenario is worsening in the city, the situation has actually been improving over the years. Marginally yes, but improving nevertheless.
The numbers are actually going down
All the data that we had at our disposal were the six columns of numbers on the Bangalore Traffic Police website. The sole dataset that we added were the population figures from 2011 to 2014. The only thing that we did was to establish relations between the different columns on a spreadsheet. It is not important to only look at numbers; it is wiser to take a closer look and establish the trends.
This is what we found: the number of accidents (both fatal and non-fatal) and the number of casualties (both killed and injured) have been steadily going down in Bangalore over the last decade. (You can download the dataset. The link is at the end of this article.)
The number of fatal accidents increased marginally from 796 in 2005 to 957 in 2007, and dropped to 703 in 2014. The number of non-fatal accidents went up from 6,782 in 2005 to 7,469 in 2007, and fell to 4,301 in 2014. In other words, cases of fatal accidents in the city have dropped by 11.68% in the 2005-2014 decade, while non-fatal incidents plummeted by 36.5% during the same period. The drop in total accidents was 33.96%. Shouldn't this be the news?
A closer examination of casualty figures tells the same story, and those are in sync with the incident statistics. The number of deaths increased from 836 in 2005 to 981 in 2007, and dropped to 729 in 2014. The number of injuries went up from 5,899 in 2005 to 6,591 in 2007, and finally fell to 4,098 in 2014. The number of deaths in the 2005-2014 decade has fallen by 12.79%, and those of injuries by 30.5%. The total number of casualties has dipped by 28.32%. Shouldn't this be news either?
A single-digit increase /decrease doesn't not make for anything exciting, but if both the number of accidents and that of casualties drop by almost one-third, it is something that needs to be talked about.
More on dropping numbers
For a city whose population is forever on the rise, a downward trend in accidents and casualties will tell yet another story.
The number of deaths for every 1 lakh of the population dropped from 8.98 in 2011 to 7.16 in 2014. During the same period, the number of injuries per lakh fell from 59.06 to 40.26. Now, those are absolute numbers. In terms of percentage, deaths per lakh have fallen by 20.28%, and injuries by 31.82%. The number of deaths per day has dropped from 2.29 in 2005 to 2.00 in 2014. The number of injuries during the same period fell from 16.16 to 11.23.
Once again, these findings are in sync with the trends established earlier. The numbers are still high, but the marked change in the decade beginning 2005 seems to be ignored by all and sundry.
So, where does the story lie?
Something surely does not sound right if one is told that the casualty/fatal numbers have been going down. The gut feeling one gets the moment one steps out on the roads does not quite match up with the statistics. So, is there something amiss here?
We, therefore, decided to look at ‘accident severity’. In simple terms, the accident severity is calculated as the number of deaths per 100 accidents (as aggregate of fatal and non-fatal) cases. It turns out that the accident severity in Bangalore has gone up from 11.03 in 2005 to 14.57 in 2014. What this means is that the chances of a person dying in an accident is higher now compared to what it was in 2005.
Yet, the accident severity index of Bangalore is not all that high. According to the Union Ministry of Road Transport of Highways, the accident severity of Bangalore in 2013 was 14.4 (our calculation shows it was 14.74). It was considerably higher than that of Mumbai (2.1) and Kolkata (9.8). But, it is certainly lower than that of Delhi (24.1), and way below the worst of the lot: Ludhiana (62.4) and Amritsar (72.6).
On the face of it, it would seem the accident severity is low in cities with high vehicle concentrations and high degrees of road congestion. For a more accurate interpretation of accident severity cases, one would need more data: from the length of roads per 100,000 of the population to road density (i.e. area under roads w.r.t the total area of the city). You also need to have congestion statistics.
The road forward
If the objective of looking at road safety statistics is to find the individual causes of accidents and, subsequently, to make life safer for a citizen, then we need more data. That would include everything from area under roads per 1 lakh of the population and number of vehicles of different types to flow of traffic and speed of traffic at different points. The scope is limitless, and that's probably scope for Big Data.
Bottomline: Bangalore's traffic police can be faulted with a lot of things; but they must also get their credit where it is due.
