News Flash

TDOT TRAFFIC COUNTS IN GALLATIN
 City Officials Note Traffic During Pandemic Impacts 2021’s Estimated Counts

Gallatin – You may have noticed rubber tubes across the streets of Gallatin. These devices, called pneumatic road tube sensors, are used by the Tennessee Department of Transportation (TDOT) to count cars along area roads. The data, collected at these count stations and released every year, gives local planners and traffic engineers information to make recommendations for congestion mitigation strategies.

City Engineer Nick Tuttle says traffic counts often show the difference between perception and the reality of traffic issues. “People will say something needs to be done about too much traffic on roads like Lock 4, Peach Valley or Cairo Road, but a look at the capacity of the roadway determined by common engineering metrics shows that there is still room for more. People who have lived here for 40 years understandably think traffic is crazy now compared to what it used to be, and I am one of those people!”

City officials say while the raw data is useful, there are problems with drawing quick conclusions from the raw data including the following:

2020 Pandemic – The closure of businesses and public gatherings drastically altered traffic patterns. City engineers and planners say this column (2020) is likely unreliable even after TDOT adjusted these numbers to compensate for irregular travel patterns.

Traffic Studies vs Traffic Counts – Traffic studies include more comprehensive data than gathered at a one-count station and are required with major road projects or developments. An intensive service analysis evaluates specifics of turn movement along a segment of road and times of peak use, which gives a better understanding of actual flow of traffic. Developers must often provide a comprehensive traffic study to the city before proceeding with a commercial development.

*Estimated Capacity (below in chart) – The estimated capacity is based upon a chosen Level of Service that takes into account the volume of cars counted on a roadway and how that effects the average travel speed. Capacities are built around roadway characteristics. For example, a four lane road is going to carry more traffic than a two lane road. If a four lane road has several intersections and conflict points such as driveways, adjustments are made in the calculation.
 
Average Annual Daily Trips 
 YELLOW SHADING = Segment over capacity    *2020 reflects TDOT adjustments due to the pandemic

Despite the drawbacks, city officials say TDOT’s traffic counts are still an important tool to observe trends and changes to roadway volume. Tuttle says the data serves as historical markers showing the impact of new roads or mitigation measures that change the routes people take as they shop or drive to work.

“For instance, taking a look at the count on Lock 4, north of Hancock, traffic on this road used to be worse than it is now. Instead of using the 109 interchange at 31 East, people were cutting off on Hancock and going up to the signal on Lock 4 to go toward Nashville,” says Tuttle. “You had some 8,000 cars on Lock 4 and then it drops when 386 is opened. Now people are going on up to Long Hollow Pike and getting on 386.”

For the complete report, including additional roadway information like peak hour volumes and historic trends can be found on the TDOT at https://tdot.public.ms2soft.com/tcds/tsearch.asp?loc=Tdot&mod=TCDS

Despite the drawbacks, city officials say TDOT’s traffic counts are still an important tool to observe trends and changes to roadway volume. Tuttle says the data serves as historical markers showing the impact of new roads or mitigation measures that change the routes people take as they shop or drive to work.

“For instance, taking a look at the count on Lock 4, north of Hancock, traffic on this road used to be worse than it is now. Instead of using the 109 interchange at 31 East, people were cutting off on Hancock and going up to the signal on Lock 4 to go toward Nashville,” says Tuttle. “You had some 8,000 cars on Lock 4 and then it drops when 386 is opened. Now people are going on up to Long Hollow Pike and getting on 386.”

For the complete report, including additional roadway information like peak hour volumes and historic trends can be found on the TDOT at https://tdot.public.ms2soft.com/tcds/tsearch.asp?loc=Tdot&mod=TCDS

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