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L H D U S E R G U I D E

D e v e l o p e d f o r V i r g i n i a D e p a r t m e n t o f T r a n s p o r t a t i o n ( V D O T )

b y C o n n e t i c s T r a n s p o r t a t i o n G r o u p ( C T G )

A u g u s t 2 0 2 0

L O U D E S T H O U R D E T E R M I N AT I O N ( L H D ) U S E R G U I D E

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O V E R V I E W VDOT’s ‘Loudest Hour Determination (LHD)’ program is regularly used by VDOT

Environmental Division and its consultants for VDOT’s environmental studies. It is a

screening program that facilitates the selection of the loudest hour based on Envi-

ronmental Traffic Data (ENTRADA, another VDOT planning program) volume and

speed outputs.

LHD was originally developed by VDOT in an excel spreadsheet format. Connetics

Transportation Group (CTG) developed this web-application (web-app) version for

VDOT in August 2020.

LHD consists of four core tabs:

1. (data) Import,

2. TNM,

3. TNM Summary,

4. (TNM) Modeling Inputs.

The ‘Import’ tab offers a streamlined input data, ENTRADA output excel file(s), im-

porting process. A user can load multiple ENTRADA output (excel) files if applica-

ble. Then the program automatically generates a road selection list and associated

summaries in ‘TNM,’ ‘TNM Summary,’ and “Modeling Inputs’ tabs.

Virginia Department of Transportation (VDOT) reserves the right to revise

LHD program. VDOT does not warrant the results or interpretation of this

program. User accepts all responsibility for the use of the program.

DISCLAIMER

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L H D P R O C E D U R E G U I D E

Col 1 Col 2 Col 3

Col 1 Col 2 Col 3

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L O G - I N P A G E

The LHD web-app require a login credential to access it. Any user without

the correct credential cannot access the web-app.

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( D A T A ) I M P O R T LHD allows importing multiple input files. Once the program reads the file(s), it

creates a roadway selection list with the roadway name(s). A user could choose a

specific roadway name from the selection list if multiple files were loaded.

The web-app presents a preview of the imported data, including project name,

starting and ending point of the road, types of the facility in existing and future

years (Interim and design), and the median types of the facilities.

The input data preview also displays three-parameter tables that include funda-

mental values such as volume demand, directional volumes, and speed infor-

mation (see next page).

Road List

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I M P O R T ( I N P U T S U M M A R Y )

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The Loudest Hour is calculated using equations and tables from the Federal Highway Admin-istration’s (FHWA’s) Traffic Noise Model (TNM) Technical Manual. The calculations are based on the data from the ENTRADA output, i.e. traffic volume, composition and speeds. The posted speeds or operational speeds, whichever is shown to be higher is used in the calculation of the loudest hour. In addition, the LHD uses reference Leqs at 50 feet for each vehicle type. It should be noted that the calculations and equations used in the web version of the LHD are the same as those that were used in the excel version, therefore no variations in results are ex-pected.

OUTPUTS

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T N M The Loudest Hour is calculated using equations and tables from the Federal Highway Administration’s (FHWA’s)

Traffic Noise Model (TNM) Technical Manual. The calculations are based on the data from the ENTRADA output, i.e.

traffic volume, composition and speeds. The posted speeds or operational speeds, whichever is shown to be higher is

used in the calculation of the loudest hour. In addition, the LHD uses reference Leqs at 50 feet for each vehicle type.

It should be noted that the calculations and equations used in the web version of the LHD are the same as those that

were used in the excel version, therefore no variations in results are expected.

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T N M - C O N T I N U E D • Directional Speeds for Existing, Interim and Design Year

This table presents speed with proportional background colors. It helps users under-

stand where the value (speed) stands compared to other values within a same column.

The biggest number (highest speed) within a column is fully filled. The other cells are

marked by its proportion to the highest speed.

• Speed

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T N M - C O N T I N U E D • 50 ft Test Receiver for Existing, Interim and Design Year

Test Receiver, the last three columns are marked based on cell values. The values are set into quantile inter-

vals. The values falling into each interval are marked with the corresponding color. Red color indicates the

highest group of the values, and light green represents the smallest group of the values.

combined

combined

combined

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C H A R T S

Test Receiver, the last three columns are marked based on cell values. The values are set into quantile inter-

vals. The values falling into each interval are marked with the corresponding color. Red color indicates the

highest group of the values, and light green represents the smallest group of the values.

• Directional LEQs for 50 ft Test Receiver for Existing, Interim and Design Year

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T N M S U M M A R Y • Loudest Hours and LEQ

Displays a summary of the loudest hours of the day and corresponding LEQ values.

T N M M O D E L I N G • Final Adjusted F-F Speed • Traffic Inputs for Worst Case Noise Hour Calculation

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U S E R G U I D E Has a download link of a PDF version user guide (this user guide).

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T h i s U s e r G u i d e w a s d e v e l o p e d f o r V i r g i n i a D e p a r t m e n t o f T r a n s p o r t a t i o n

( V D O T ) b y C o n n e t i c s T r a n s p o r t a t i o n G r o u p ( C T G ) , h t t p s : / / c t g c o n s u l t . c o m