http://www.digitaljournal.com/article/270847

Relax and go with the flow: study shows comfort is key to speed

Posted Apr 12, 2009 by Nikki Weingartner
In a state with over half of its roads made of gravel, a study targeted at drivers on those roads shows that comfort is key when choosing a speed.
A recent study at Kansas State University shows some pretty interesting finds with regards to the effectiveness of speed-limit signs. People just go with the flow, it seems, basing their driving speeds on conditions and perceptions instead of number limitations.
Because over half of the Kansas road system is made up of around 80,000 miles of gravel roads and most of those roads do not post the maximum speeds, drivers in the state are essentially left to their own devices when making their way from point "A" to point "B."
The maximum speed limit in the state of Kansas is 55 miles per hour for gravel roads, regardless of whether or not it is posted. Local lawmakers can reduce those speeds within their own jurisdictions.
According to information from the University:
researchers monitored 41 sites, each for about one week. They looked to see if there was a difference between actual driving speeds and the speed limit. The researchers also looked at various factors like the different types of gravel roads; the number of crashes on the gravel roads; the width of the roads; the amount of heavy vehicles and traffic parameters like volume. Additionally, the researchers sent surveys to residents living near gravel roads. Dissanayake said the project only looked at straight sections of roadways and avoided curves, slopes, bridges and other factors that likely would affect the drivers' speeds.
The researchers found that people drove faster when gravel roads were sandier and when they were wider. They also found that heavy vehicles drove faster than smaller vehicles. However, when it came to speed limits and the actual speeds driven, the difference was not significant between 35 mph and 55 mph roads.
One county in Kansas did have a lower limit on its gravel roads than the others, actually posting a 35 mph speed limit. A post that creates problems for drivers according to the study researcher, Sunanda Dissanayake.
Overall, the study found that there was no benefit to reducing speed limits on gravel roads as people tended to stay under the limit. It also found that people simply drive at speeds with which they are comfortable instead of sticking to a number. The crash rate was relatively the same as other roads. However, the money spent on posting speed limit signs as well as sign maintenance would essentially be a waste of funds and as researches claim, could serve to reduce driver respect:
"The only thing is that you might lose the respect of the drivers. The majority are driving under the speed limit, so why do you need to lower it?"
The study was targeted to gravel roads, however, and extrapolation onto paved highways would be highly inadvisable.
Study results will be presented next week at the Kansas Transportation Engineering Conference.