Saturday, June 25, 2022

Trying to change speed limits in your neighborhood? It’s not as easy as you might think

Residential speed limits get slightly different treatment compared to main corridors. (Port City Daily/File)

WILMINGTON — Speed limits are intended to keep residents and drivers safe, but they can also be the cause of frustration.

It is not uncommon to see neighbors taking to social media to complain about a speed limit in a neighborhood (usually) or on a connector street. Other times you might see discussion of having speed bumps installed in a neighborhood or online petitions advocating for a mixture of the two — but how easy is it to change a speed limit or request speed bumps be installed?

While they might seem arbitrary at times, speed limits actually take time to set and require engineering and traffic studies to be conducted (most of the time). North Carolina Department of Transportation Division 3 Traffic Engineer Jessi Leonard helped explain what it takes to set speed limits and how they can be changed.

First things first, when talking about residential roads interested parties need to know if the street is state-owned or maintained perhaps by an HOA or road maintenance organization. If it is not state-owned and maintained, then drivers should address whoever is actually in charge of that street with any concerns — not the NCDOT.

Speed limits on public roads are controlled by the state. Even if there are no speed limit signs, there are still some standards in place.

“Speed limits are controlled by general statutes and local and state ordinances. Within incorporated municipalities, the statutory
speed limit is 35 miles per hour (MPH) unless otherwise ordinanced and posted. The statutory speed limit on roads outside incorporated municipalities is 55 MPH unless otherwise ordinanced and posted,” according to the NCDOT.

More often than not, there are posted speed limits on the roads around Wilmington — but how exactly are these speeds determined?

The NCDOT utilizes what is known as the 85th percentile speed to help guide and set speed limits. Essentially this is the average speed that 85% of drivers are traveling on a road under free-flowing conditions, regardless of the speed limit.

“We usually rely on that [85th percentile] pretty heavily because typically people will drive a road at a speed they feel comfortable, regardless of the signage unless there is strict enforcement,” Leonard said.

The 85th percentile tool was cited as the reason why the NCDOT was not in favor of lowering the speed limit on Dow Road in Carolina Beach when it was requested by the town. Essentially, the state said that since the lowering of the speed limit would likely not be followed it did not support the change.

If the 85th percentile speed is faster than the posted speed limit the NCDOT suggests strict enforcement to get compliance.

“The location that I typically use in this area is MLK, they [police] are constantly sitting out there so people do tend to go that speed limit even though it feels like you might be able to do a little faster on that road,” Leonard said.

Exceptions in residential areas

While speed studies are generally conducted to lower or raise speed limits, residential roads are treated a little bit differently, Leonard said. In areas like those in Ogden around the White Road and Harris Road areas, speed limits were recently dropped to just 25 mph. This has prompted discussion on social media to the reductions and some complaints about the new lower speed.

When determining the speed on roads in residential areas the NCDOT takes things into account like the number of homes and driveways entering on the road, pedestrians, and in the case of Harris Road, the fact Smith Creek Park is located on it.

But these things don’t just happen, according to Leonard the NCDOT used to receive numerous complaints on a regular basis asking for speed reductions in the Ogden area.

While the 85th percentile speed is typically used to justify lowering of speed limits, in the case of Harris Road, this survey was not conducted.

“We didn’t do an 85th percentile speed for the most recent request that we received … the last one we did the 85th percentile was 31 mph on that road,” she said.

Since the 85th percentile speed did not justify the lowering of the speed limit on Harris Road to 25 mph at the time of the study, it was not lowered. Recent changes at the state level had made it easier for the NCDOT to go against the 85th percentile speed test when lowering speed limits.

In the past, if a speed limit were to go against the results of the traffic study a survey had to be conducted for all the residents that would be affected by the change, Leonard said. But sending the petition to thousands of households proved challenging for the NCDOT and to get a majority of those surveyed to actually complete the questions and return it often proved difficult.

“It was a lot of footwork for not much return,” she said.

Because of this regional traffic engineers approached the state-level engineers and requested that residential areas be treated differently allowing changes without these studies being conducted. The request was granted — which is how speed limits are able to be changed without surveys conducted.

While the NCDOT did take action based on residents’ complaints, Leonard admitted it would be more difficult to convince the NCDOT to raise previously lowered limits back up to a higher speed. But, if there were formal complaints submitted to the NCDOT, the issues is something that could be investigated.

Traffic calming devices

Speed humps are slightly less aggressive than ‘speed bumps’ and the NCDOT does allow their installation but only after studies along with petitions are conducted. (Port City Daily/File)

Frequently homeowners will call for the installation of speed bumps or even request additional stop signs to slow traffic — but these are not always a good option from NCDOT’s point of view.

“It is often believed that stop signs, traffic signals and speed bumps will control vehicle speeds. While stop signs and traffic signals are important traffic control devices, they are not used to control vehicle speeds. The purpose of stop signs and traffic signals is to assign right of way at intersections. Overuse of stop signs and traffic signals reduces both their effectiveness and driver compliance,” according to the NCDOT.

The NCDOT does allow the installation of what they call ‘speed humps’ — but only in certain instances.

There is a pretty lengthy process, which includes a petition of the neighborhood that requires 60% approval, for the installation of speed humps, Leonard said.

If the petition does reach the required level then the NCDOT requires those requesting the installation — often an HOA — to commission and fund a traffic study to see how the speed humps would impact other roads and intersections on the state roadway system.

Ultimately, changes to speed limits and the addition of traffic calming devices take time and energy and are, in general, anything but arbitrary.


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