Did use of helmets reduce deaths due to 2 wheeler accidents?

This blog post is about the analysis of implementation of helmet rule in various Indian states and the effect it had on bringing down accidental deaths due to 2 wheelers. Here we are specifically focussing on one particular state, Karnataka.
               National Mandatory helmet legislation is included in the Indian Motor Vehicles Act, 1988.  However, implementing this law has been left to the individual states. Karnataka gov. enforced mandatory helmet rule for all 2 wheeler riders in the year 2007. Traffic cops started imposing fines to violators of the rule and within no time, good compliance to the rule was observed. Accidental Deaths & Suicides in India publicizes the data about accidental deaths broken down by type of vehicle and by state (from 1967 to 2009). Considering the state of Karnataka, looking at the accidental deaths due to 2 wheelers and plotting the trend we see a clear decline in accidental deaths after 2007, specifically 8% decline in accidental deaths as of 2009. But can we just attribute this drop in accidental deaths to the helmet rule? Let’s explore.
               Let’s identify another state (to control for helmet rule) which had similar accidental deaths pattern over the years before 2007 and was not a strict enforcer of the helmet rule. If we see a dip in accidental deaths in this state, we can pretty surely conclude helmet rule did not have any influence in bringing down the accidental deaths. Interestingly by analyzing accidental death patterns across different states, neighbouring state Tamil Nadu (TN) had similar accidental death patterns over the years before 2007 and was not strict enforcer of helmet rule (violators were not penalized often).
              The figure below shows accidental deaths plotted for both these states starting from 2001 to 2009. Until 2007, the accidental deaths have been observed to increase year on year in both these states. However post 2007; Tamil Nadu continued to see increase in death rates due to 2 wheeler accidents for the next two years up to 2009 as Karnataka showed a decline in accidental deaths. Triangulating the above points, strict enforcement of Helmet rule in Karnataka helped bring down the accidental deaths due to 2 wheelers.

Helmet Rule - Effectiveness Analysis

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