Interesting Findings

Using our application we came across different interesting findings. For each one of them we found

an historical event that explains the different trends in the graph. Let us list down the findings

and the related events.

2003 - Illinois decrease in car crashes

If you look at the data for Illinois you can see how, starting from 2003, there is a decrease in the 

number of car crashes. We looked for an event that could explain this phenomenon and we found 

out that starting from 2003 the Illinois state forced the drivers to wear their seat belts. When a 

law is perceived as meant to enhance safety, the drivers result to be more responsible and careful.

You can find more informations here:

• http://www.corboydemetrio.com/news-publications-118.html

2004 - Virginia Speed Laws

If you look at the data for Virginia, you encounter a strange phenomenon. The number of crashes

increases, starting from 2004. You could think that the speed limits or the alcohol limits got less

severe, but it's the opposite. In 2004 the state of Virginia passed a few law that made the speed 

limits more strict. The result was the opposite, as the number of car crashes started to increase. 

You can find on the web some very interesting researches about this strange correlation about 

speed limits and car crashes. More info here 

• http://www.livescience.com/3870-higher-speed-limits-deaths-study-finds.html

• http://www.realbeer.com/discussions/showthread.php?t=3733

2006 - Michigan updates speed formulas

The number of crashes starts decreasing since 2006 in Michigan. In that year the state decided

to update its speed formulas to calculate speed limits. This resulted in a decrease of car crashes, 

showing that when we deal about speed limits, it's not just a matter of decreasing them, but 

set them at a right level. More info here:

• http://www.michiganvotes.org/2005-HB-5240

2008 - Gas Price Report, April 2004 - December 2008, Mississipi

"The results suggest that prices have both short-term and intermediate-term effects on reducing traffic

crashes also shows gas prices having a short-term impact on crashes involving younger drivers and 

the intermediate-term impact related to older drivers and men (short-term impact refers to immediate 

effects, for example how a current month's average gasoline prices affect the same month's traffic crashes. 

Intermediate-term impact refers to effects over a one-year subsequent time period)

also found significant connections between gas prices and a reduced frequency of alcohol-related crashes

conclusion: higher gas price reduces alcohol-related crashes, reduces younger better than older, 

reduces overall frequency and rate of crashes."

Sources:

• • Research paper here: 

    • http://nexus.umn.edu/Papers/GasPricesAndDrunkDriving.pdf

  • Reports here: 

    • http://blog.lib.umn.edu/levin031/transportationist/2011/04/gas-prices-rise-accidents-drop.html

2009 - South Carolina DUI Law Changes

Last but not least, we had a look at the data from South Carolina. From 2009 there is a decrease in the number 

of crashes. This is possibly due to the changes in the DUI Laws that took place that year. Alcohol limits 

were made more stricts and punishments more severe. Alcohol is on of the major causes of car crashes, therefore

one of the most effective variables of the problem.