By Dr. Paul Roberts and Joe Croughwell
One of the major arguments for building the Sea Islands Greenway is that the existing roads are unsafe. The best way to correct the problem is to build a new road to modern highway design standards on a protected alignment. The critics of this approach argue that problems with the safety of the current roads could be solved by simply increasing the enforcement of current speed limits, along with a few inexpensive improvements to the existing roads. Their bottom line—no new roads are necessary! The information presented here should shed light on that position. This report is an update of one that was done in late 2009 using the 2007 and 2008 data available at that time for accidents on Johns Island roads and their approaches, principally Route 17 and Maybank Highway.
In 2008, the Post and Courier carried an article reporting on a study prepared by a non-profit Washington DC transportation research group, TRIP, showing that two of the major routes on Johns Island – Bohicket/Main/Betsy Kerrison (SC 20) and River Road (SC 54) – were among the most dangerous in the state. They used accident data gathered by the South Carolina Department of Public Safety and found that from 2003 through 2006 there were 22 fatalities on Johns Island roads. Of these, nine of the victims were residents of Johns Island, eight were from Charleston, and the remaining five were from other communities in the region. In addition to the 22 dead, 11 people were seriously injured. These accidents can be directly attributed to the antiquated design, congestion, and condition of the roads themselves. Unfortunately, limitations in the data available from the Department of Public Safety at the time of this original article made it impossible to know where the accidents occurred or, more importantly, what caused them.
New data on accidents for 2007 and 2008 were obtained in late 2009, and the 2009 data has recently become available from the SC Department of Public Safety. This new data, reported by police officers on the scenes of the accidents, is quite detailed. Taken together, the 1,498 observations of automobile accidents on Johns Island and its approaches recorded during these three years shows what is happening on the roads, and answers the most frequently asked questions—where did they occur? When? Why?
Note that in 2006, Johns Island had roughly 15,000 residents, yet more than 50,000 vehicle trips entered and left the island in a day. Since 2006, nothing has been done to change the dangerous conditions. By 2035, the volumes traveling on and off the island will approach 80,000 trips per day. If the I-526 extension is not built, trips crossing the Stono Bridge alone are forecast to reach almost 43,000 vehicles per day. This is clearly a recipe for disaster. With this growth in traffic, the grim statistics will continue. The need to understand the accidents, what caused them, and what can be done to improve the situation has merely increased with the growth in traffic levels.
In the three-year period (2007 through 2009) covered by the new data, there were 1,498 recorded accidents, 527 of which led to a total of 691 injuries. Most important, there were 17 deaths. The overall accident rate on Johns Island is just short of 10 accidents per week. Eighty-six percent of the accidents took place on four roads—Maybank, Main, River and Bohicket. Maybank Highway and Main Road had more accidents and more injuries than the other roads, but River Road had the most deaths. The four deaths on River Road can be attributed to its narrow travel lanes, sharp curves, lack of shoulders, and the fact that the shoulders are overgrown with century old Live Oaks right next to the edge of the pavement.
Most of the accidents and most of the deaths took place on dry pavement, in clear weather, and during the daylight hours. The most frequently cited cause of accidents is that the driver was “distracted or inattentive.” Surprisingly, in this database the category “exceeded speed limit” is not even in the top ten of the list of probable causes of accidents on Johns Island. In fact, it does not appear until 14th on the list, below a number of other common probable causes.
A not too remarkable fact that comes out of the data is that trees play a major role in mortality, accounting for 41% of the accidents involved when there is a death. This is due to the nature of the tree-lined roads on Johns Island. In fact, hitting a tree was a part of 128 of the accidents, 78 of the injuries and seven of the 17 recorded deaths. The problem is obvious. The roads on Johns Island have the same antiquated design standards they had when they were upgraded from the two-lane gravel roads that have existed since the turn of the last century. Traffic volumes, already heavy on these beautiful tree-canopied roads, continue to increase as the area grows. If the driver encounters something unexpected, there is no place to go. The vehicle hits one of the roadside trees. The greater the traffic density, the more likely there is to be an accident and the higher the death and injury rates. Maybank Highway has the largest traffic volumes. It also has, by far, the most accidents and also the most injuries. The irony is that no one wants to cut down the trees. They are what define the rural character of Johns Island. They are why most of us live here.
What can be learned from the new data that will help slow the accident rate on Johns Island roads and stop the carnage? Two things appear to emerge from the data. First, it should be apparent that increasing police enforcement on speeding on Johns Island roads would help, but it will not stop inattentiveness, failure to yield the right-of-way, following too closely, animals in the road, fatigue, medical problems, faults with the vehicle, driving under the influence or any of the 34 other probable causes of the accidents reported in the database.
Second, widening existing roads will increase capacity on the roadways and make it easier and safer for traffic, but unless we are willing to cut down the roadside trees they still threaten safety. One must consider the rate of growth over the past years, the future development potential of the area, and the wishes of present residents of the island who want to retain the island’s rural character. With this in mind, the solution that makes the most sense is the one recommended by five separate engineering studies over the past 20 years – to remove traffic from the existing roads by diverting it to a new alignment where the roadway can be constructed to modern standards that will improve safety and accommodate current and anticipated traffic levels.
Joe Croughwell is the Enforcement Officer for the Kiawah Island Community Association (KICA) and Dr. Paul Roberts is the Traffic Consultant for the Town of Kiawah Island.