Unifying Alabama's Traffic Safety Efforts
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Weather


This page is dedicated to studies and information related to severe weather impacts on communities, including transportation, economic, and civil impacts. The recent winter weather impacts of the 2014 season have created multiple complications for the public, schools, and businesses in many regions of the country. See the article on the Alabama crash analysis for the late January 2014 ice and snow event that crippled the I20-59 corridor. This article contains recommendations on severe winter weather driving that were learned from the analysis of crashes during this event. See also the article on the effect of weather on crashes to learn about the numerous factors associated with severe weather crashes.
Climate Change: A Hot Topic at DOT
USDOT: Today, about 27 percent of America’s GHG emissions come from the transportation sector – second only to electrical power production at 34 percent.

Click Here to Read More

Picture of ship and ice


New Weather Study
Recent CAPS crash data weather study showed that crash frequency increased approximately 40% on wet weather days.  Click for complete study.
Alabama Crash Analysis of the Last Week of January 2014
As part of the Center for Advanced Public Safety (CAPS) at The University of Alabama's ongoing studies to improve traffic safety in Alabama and the nation, a study was conducted to focus on the dramatic increase in crashes that occurred in Alabama as a result of the rare ice and snow storm that occurred beginning early on Tuesday, January 28th and continued throughout the day. Traffic was affected for most of the rest of the week.

In order to keep the difference between weekday and weekend traffic from creating a complicating factor, the entire last week (seven days) of January in 2013 and 2014 were used to make the comparisons. This would then account for the changes in traffic flow that might have resulted from the pre-storm warnings as well as the aftermath of the storm itself.

The following gives an overview comparison of the number of crashes by severity for the two weeks being compared:

Severity

Jan. 25-31, 2013

Jan. 25-31, 2014

Fatal

14

12

Severe Injury

251

216

Possible Injury

178

201

Property Damage Only

1479

1921

TOTAL

1922

2350


The increase in the total number of crashes was quite significant, at 22%. However, this increase came totally from the lower severity crashes. Both Fatal crashes and Severe Injury crashes decreased (a combined 14% decrease). This is not unusual in weather-related crashes in that most motorists have the training and common sense to slow down when the pavement is slippery. In some cases around the urban areas the traffic came to a standstill or was greatly impaired forcing drivers to slow down.

Crash density maps were developed to provide a feel for the general location of the crashes, especially as they relate to the Interstate highways and the large cities. The first map below shows the overall crash density for the storm week. A comparison of this with the comparable 2013 map showed no significant differences, essentially establishing that the crash density effects of the storm were about the same statewide.
Crash Density Maps for Week of Ice/Snow Event

All Crashes


Severe Injury and Fatal Crashes

In order to see the change in location with respect to severity, a comparison of two maps were found to be most interesting. One contains all of the crashes and the other contains the more severe crashes. The most impressive fact that emerges from a comparison of the two is the dramatic shift of the more severe crashes from the urban areas where the traffic was most dense to the rural areas, where speed becomes much more of a factor. It also becomes clear that the more severe crashes tend to move away from the Interstates and onto the county road system. The overall shift was from 25% rural crashes in 2013 to 29% rural crashes in 2014, which was a relatively small but significant increase. Of the 12 fatal crashes that occurred in 2014, 11 were in rural areas. This is a dramatic increase from 2013, where only four of the fatal crashes were in rural areas.