DOT Studies

When we moved to Isle of Pines Road in Mooresville four years ago, I was startled that the upper end of our road, a fully residential one, had a posted speed limit of 45mph for its first b 1.5 miles. By my count that section of road has roughly 24 driveways directly connecting with the two lane, double yellow lined road. That count does not include the four residential developments that feed onto the road.  The smallest development in the 45mph zone has at least a dozen houses that connect to IoP Road.

In early August I contacted the Iredell Sheriff’s Department which referred me to Mr. Touger Yang, Assistant Division Traffic Engineer, Division 12,North Carolina Department of Transportation. I requested that the 45 zone be reduced to 35 because the road is a residential one with a double yellow line, and is heavily used by cyclists, runners, walkers, deer, and motorists. I share his response:

“We still do not recommend reducing the speed limit on Isle of Pine Road to 35 mph. The development in the 45 mph section of the road is 22% (23 driveways, 1.49 miles). The development in  the 35 mph section of the road is 57.4 % (16 driveways, 0.40 mile). The 35 mph section of the road was not lowered based off development. The 35 mph section was lowered to help motorist reduce 10 mph into the 25 mph section and not 20 mph if the speed limit was 45. The 25 mph section has steady horizontal alignment changes and the development on the road is 82% (36 driveways, 0.63 mile).

We did not conduct a spot speed study on the road. However, from a previous study in 2017 the average speed in the 45 mph section of the road was 43 mph – 44 mph and the 85th percentile speed on the road was 50 mph – 53 mph. The 85th percentile speed is typically what we use to determined posted speed limits on a road +/- 5 mph. Please contact law enforcement if you have issues with speeding on the road.”

He referred me to his superior, Mr. Byron Engle.

I contacted Mr. Engle and offered some corrections to Mr. Yang’s letter. It is very important that in the 35 speed zone there are only SEVEN driveway directly connected to the road and they all are on the east side of the road and a developer’s berm is on the west side. Here is his response.

I apologize for the delay in responding to your request for a lower speed limit on Isle of Pines Road.  I was waiting on an updated spot speed study since the previous one was done in 2017.   The 2021 study revealed that the average speed was 45 mph which is very close to the 44 mph average from the 2017 study.  Since motorist are traveling at the posted speed, we do not recommend lowering the speed to 35 mph.  This is comparable to other roads in the area such as Stutts Road, McKendree Road, Chuckwood Road as well as the three-lane and two-lane portions of Brawley School Road.  All of these roads have areas of development with appropriate speeds based on the concentration of homes, businesses and other development.

When we look at development, we are looking at homes, businesses, etc. that have a direct connection to the road.  This is different from a subdivision which may have one, or more, entrances onto the road that provide the access for the homeowners living there.  When comparing the number of direct connections it is greater in the 35 and 25 mph sections than in the 45 mph section.  Therefore the speeds on Isle of Pines are appropriate and reasonable.

            In his great book, Too Soon Old, Too Soon Smart, Dr. Gordon Livingston offers thirty true things that he learned through experience, and he thinks we all should know them. His first true thing is, “If the map doesn’t agree with the ground, the map is wrong.” He then shares how when he was a young officer in the 82nd Airborne and in heavy woods at Ft. Bragg , he was studying  his map. His platoon sergeant, a “veteran of many junior officers” asked if anything was wrong. Lt. Livingston pointed to some trees and said that the map indicated that a hill should be there. The masterful sergeant gave Livingston his first true thing.

            Both DOT administrators quote studies, one as old as from 2017, to justify the 45-mph speed limit on Isle of Pines Road. Mr. Engle also refers to other similar roads which have a 45-mph limit. One of those I know—Stutts Road also needs a lowered speed limit.   I live here, drive the road almost every day, and see the traffic. Mr. Engle and Mr. Yang are like Dr. Livingston’s map that quotes rules and regulations while ignoring the reality of the ground. The ground here is not suited to a 45mph zone. I wish they each would come here and drive 44 miles per hour in the 45 zone and see if it is safe.  I asked them both to, in order for the safety of everyone, to reduce the speed.

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