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May 6, 2020

COVID-19 Shutdown Affects Traffic in NC (Part 3 of Series)

Dr. Jeremy Chapman, PE. PTOE, JD, RSP1, with Ramey Kemp Associates, has worked from home for over three years and shares a few tips that might be helpful for newbies.

The first two parts of this series focused specifically on the effects being seen in North Carolina. This part is instead looking at two different, but interconnected, phenomena that have been highlighted by the severe decreases in traffic, not just in North Carolina, but nationally. Specifically, the reductions in traffic due to the pandemic offer the opportunity to reflect on the future of traffic, safety, and urban land use, as we see the substantial amount of space dedicated to motor vehicles that now stands nearly deserted.

First, reported trends show that while the number of crashes is down (as one would expect with the substantial decline in traffic volumes) the severity of the occurring crashes is higher than typical. I believe there are several factors behind this phenomenon from a traffic safety standpoint, especially as these reports tend to come from urban areas.

One feature of major urban areas typically is a large loop-type freeway (often referred to as a beltline, beltway, or something similar). These serve multiple purposes, often to connect outer suburbs to each other, and to also provide a bypass to enable through traffic to avoid going through a more-congested downtown area. Traffic volumes on these loops can easily exceed 100,000+ vehicles per day in normal conditions, and often are congested during multiple hours daily. To accommodate this level of traffic these roads often are 4-5 lanes wide in each direction with minimal turning. This creates a wide, open space where vehicle speeds are often only limited by the congestion itself. Given their urban nature, these loops are often posted at 55mph or higher, and anecdotally, during off-peak times in normal conditions, these speed limits can easily be exceeded by 25+ mph. Now, with the much lower traffic volumes, it is effectively off-peak all the time, so drivers may not find anything limiting their speed. If some drivers take advantage of this opportunity, it can result in significant speed differentials between drivers obeying limits and those choosing to ignore them.

A significant amount research (both in the United States and internationally) has explored the relationships between vehicle speed & crash risk and vehicle speed & crash severity. These relationships are clear, that as vehicle speed increases the risk of a crash increases, and similarly that as vehicle speed increases, the severity of any crash also increases. The research has also shown that speed differentials between vehicles traveling on the same roadway in the same direction contributes to both the risk of, and the severity of, a crash. While it has always been important to find ways to reduce these resulting speed differentials, now that we are seeing “off-peak” traffic all the time, that need is even greater. While traffic will eventually return to something resembling pre-pandemic levels, that may take several years if past economic downturns are any indicator.

Given what is already known from research prior to the COVID-19 pandemic, and the experiences being documented during the pandemic across the country, we may be learning a lesson from our desire to keep making roads bigger, wider, and straighter. There may be value in applying methods, such as zipper lanes, to reduce the available lanes on roadways when the excess capacity is not needed. Research indicates this limitation on opportunities to travel far above the posted speed limit would reduce both the speed-based crash and speed-differential crash risks, and thereby reduce the disproportionate crash severity as well.

The second, interconnected, phenomenon that we are seeing is the amount of empty pavement that is normally dedicated to personal passenger vehicles (cars, SUVs, and pickup trucks, primarily). An April 20th article on TheAtlantic.com by Tom Vanderbilt titled “The Pandemic Shows What Cars Have Done to Cities” (well-known for his book Traffic: Why We Drive the Way We Do), shone a light on the substantial amount of real estate dedicated to vehicles through roads, on-street parking, and off-street parking that exists in most cities. When this space is filled with vehicles, it is far less apparent how vast it truly is, but with the nationwide shutdowns due to COVID-19, the full picture becomes far more evident with its emptiness. It also highlights how we have often managed to find this extra vehicle space in built-up urban areas – by stealing from the sidewalks. Now that the roads are far emptier and we are constantly being told to maintain a 6-foot spacing from others, we are finding it a challenge to do so with the space that is left.

This space issue is becoming even more evident as states start to slowly allow the reopening of businesses. The common allowance is operating at 50% capacity, but this is for establishments where masks can be worn. In restaurants, the requirement for masks becomes inherently more difficult as eating and drinking while wearing a mask, frankly, does not work. Restaurants are instead asked to separate tables by a minimum of 6 feet, which can often reduce their capacity far below 50%. In Asheville, NC, as well as many other cities, there is a push by restaurant owners to allow outdoor dining. Finding the space to accommodate these requests is the new challenge. Several cities nationally are considering, or have decided to close part, or all, of some streets to accommodate outdoor seating for their restaurants. Others are considering a variety of options such as the use of public parks and long-term use of on-street parking spaces as constructed parklets as spaces for restaurants to host dining alfresco.

So, what to do about all this dedicated space? Now is the time to have serious discussions about what is truly needed. In 1974, Madison, Wisconsin closed State Street from the State Capitol building to the University of Wisconsin campus. The road was partly reconstructed in the process, removing travel lanes, and creating extra-wide sidewalks on both sides of the street. The result was a limited-access road that has been incredibly successful for the many stores, bars, theatres, and restaurants that line the eight blocks, despite having only pedestrian access to their entrances. Almost 50 years later, this road is still limited access, and prior to the pandemic, was always bustling. The closure (or partial closure) of roadways does work, especially when sufficient parking is available a block off the closed road (as is the case in Madison), and should be widely considered. Cities, and especially urban cores, can be a place to drive to, not just a place to drive through (quickly)…safety for anyone not in a car depends on it.

Finally, what does this “excess” space really look like? A poster that has long circulated online illustrates it quite well:


Ramey Kemp Associates
Dr. Jeremy Chapman – PE, PTOE, JD, RSP1
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