It is common wisdom that driving in the rain is harder, but does it really lead to more car accidents? Every year in the U.S., there are approximately 5,870,000 accidents and of those, 23% or 1,300,000 are due to bad weather. Digging deeper into the data, we find that 16% of injury crashes and 13% of fatal crashes involve wet pavement or rain specifically.
I was surprised to learn the number is that low since every time we have a downpour in Atlanta, the highways seem to fill with crashes and the unfortunate few that get injured are the evening news.
Turning to Georgia specifically, according to the Georgia Department of Transportation’s 2008 study, Georgia averages 2,300 crashes per day and in Georgia an average of 31 people die each week in car accidents. That is shockingly high. Georgia has not done much in the way of studying rainfall’s correlation with crashes however. A California Highway Safety Patrol study concluded that there were about double the number of crashes on a rainy day versus a dry day.
One of the most fascinating observations is the drastic effect that dry spells prior to rain have on the rate of injury crashes. A study out of India determined that even a one day dry spell before a rainy day increased the frequency of rainy day crashes by 9.7%. If there were six days of dry weather during which oil could build up on the road way, the rate rises to 17.9% and 23.1% after a 21 day dry spell. Are Road Accidents Affected by Rainfall? A Case Study from a Large Indian Metropolitan City British Journal of Applied Science & Technology 1(2): 16-26, 2011
The takeaway from this is, rainy weather driving after a lengthy dry spell is extremely dangerous. Increased following distances and an avoidance of nightime driving during these conditions is wise. Be safe out there.