APPENDIX A: SURVEY TRANSMITTAL LETTER AND QUESTIONNAIRE

Appendix A includes the survey transmittal letter that was distributed to TRB state representatives and all 31 questions of the online survey.

TRANSMITTAL LETTER

Dear First Name Last Name,

The Texas A&M Transportation Institute, under the Transportation Research Board’s National Cooperative Highway Research Program (NCHRP), is conducting Project 07-30 Methods for Assigning Short-Duration Traffic Volume Counts to Adjustment Factor Groups for Estimating AADT. The objective of this project is to develop rational methods for assigning SDCs to adjustment factor groups for estimating AADT. The research is concerned with all roadway functional classes and traffic volumes. More information on the project is available here (https://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=4945).

NCHRP is sponsored by member departments of the American Association of State Highway and Transportation Officials (AASHTO), in cooperation with the Federal Highway Administration (FHWA), U.S. Department of Transportation. All the state highway and transportation departments contribute funds annually to fund the program.

Task 2 of the project involves evaluating and identifying assignment methods for further consideration in Phase II of the research. One of the research activities in Task 2 is to conduct an online survey of state Departments of Transportation on the development of adjustment factor groups and assignment of factors to SDCs. The purpose of the survey is to (1) document relevant state practices, (2) capture potential implementation considerations and challenges, (3) identify states’ needs and potential areas for improvement, and (4) identify agencies who could potentially provide the research team with probe data in Phase II of the project.

The survey has been sent to the TRB representative of each state. The survey should be completed by those who manage traffic monitoring programs/centers and have specific knowledge and experience in AADT estimation, development of adjustment factor groups, and assignment of factors to SDCs. Please forward this request to the appropriate contact within your agency.

Follow this link to the Survey:
Take the Survey

Or copy and paste the URL below into your internet browser:
https://tti.qualtrics.com/jfe/preview/SV_1Uq64W6kCkd1Hf0?Q_CHL=preview

The survey contains 31 questions and takes approximately 20 minutes.

Please complete the survey by February 28, 2022.

I realize that you receive many inquiries like this and that the time they require is not insignificant. Thank you for your efforts. Your assistance will help the research team develop meaningful guidelines that will benefit the traffic monitoring community and those who use AADT as input in various analyses and applications. Please, don’t hesitate to contact me if you have any questions.

Sincerely,
Ioannis (Yianni) Tsapakis, PhD
Research Scientist
Texas A&M Transportation Institute

SURVEY QUESTIONNAIRE

Survey for NCHRP 07-30—Methods for Assigning Short-Duration Traffic Volume Counts to Adjustment Factor Groups for Estimating AADT

Introduction

This survey contains 31 questions related to the assignment of adjustment factors to short-term counts. The questions are divided into the following topics:

• Data collection
• Adjustment factor groups
• Assignment of short-term counts to adjustment factor groups
• Implementation process

Your input is critical for developing rational assignment methods and useful research products that will benefit the traffic monitoring community and ultimately those who use AADT as input in various analyses and applications.

The survey should take approximately 15-25 minutes. Please complete it by February 28, 2022.

Thank you!!
Ioannis (Yianni) Tsapakis, PhD
Research Scientist
Texas A&M Transportation Institute

RESPONDENT INFORMATION

Full Name ___________________________________________________

Title ________________________________________________________

State Agency _________________________________________________

Phone _______________________________________________________

Email _______________________________________________________

Acronyms used in the survey:

6R: Rural minor collectors

7R: Rural local roads

7U: Urban local roads

FC: Functional class

A. DATA COLLECTION

1) How many short-term count sites do you have (optional)?

On all FCs

On lower FCs: 6R, 7R, 7U

2) How many short-term counts do you conduct every year (optional)?

On all FCs

On lower FCs: 6R, 7R, 7U

3) What days of the week do you conduct short-term traffic counts? (please select all that apply)

□ Monday

□ Tuesday

□ Wednesday

□ Thursday

□ Friday

□ Saturday

□ Sunday

4) Do you conduct short-term counts all year long?

• Yes
• No

5) Which months of the year do you take short-term counts as part of your coverage count program (not the special needs count program)? (please select all that apply)

Note: Q5 is displayed if the answer selected in Q4 is “No”.

□ January

□ February

□ March

□ April

□ May

□ June

□ July

□ August

□ September

□ October

□ November

□ December

□ Add comment(s), if necessary:

6) What is the typical duration of your short-term counts conducted as part of your coverage count program? (please select all that apply)

□ Less than 24 hours

□ 24 hours

□ 48 hours

□ 72 hours

□ 96 hours

□ 7 days

□ 14 days

□ Other (please specify)

7) How many active permanent/continuous sites do you have?

On all FCs

On lower FCs: 6R, 7R, 7U

8) Are you considering to use probe data/estimates (e.g., probe AADT estimates) in the future?

• No (please explain)
  
• Yes (please explain)
  

9) Has your agency subscribed to or purchased probe data/estimates from one or more data vendors?

• No
• Yes, from 1 vendor
• Yes, from 2 vendors
• Yes, from 3 vendors
• Yes, from 4 vendors
• Yes, from 5 or more vendors

10) How many months of probe data do you have from each vendor?

Note: Q10 is displayed if one of the following answers are selected in Q9: “Yes, from 1 vendor”, “Yes, from 2 vendors”, “Yes, from 3 vendors”, “Yes, from 4 vendors”, “Yes, from 5 or more vendors”.

	<12 months	12-24 months	>24 months
Vendor A (enter name)	◦	◦	◦
Vendor B (enter name)	◦	◦	◦
Vendor C (enter name)	◦	◦	◦
Vendor D (enter name)	◦	◦	◦
Vendor E (enter name)	◦	◦	◦
Vendor F (enter name)	◦	◦	◦

11) Would you be able to support Phase II of this NCHRP project by providing us with probe data? (In Phase II, the research team will use raw point, trajectory, or trip count data from different states and vendors to develop and examine the accuracy of probe-based adjustment factors)

Note: Q11 is displayed if one of the following answers are selected in Q9: “Yes, from 1 vendor”, “Yes, from 2 vendors”, “Yes, from 3 vendors”, “Yes, from 4 vendors”, “Yes, from 5 or more vendors”.

• No
• Yes
• Maybe (please explain)
  

12) Have you (or another agency in your state) computed or examined the accuracy of adjustment factors developed from probe data?

• No
• Yes (please provide more information below)
  

B. ADJUSTMENT FACTOR GROUPS

13) How do you calculate adjustment factors for each permanent site? (please select all that apply)

□ In-house, we use Microsoft Office Excel and/or Access

□ In-house, we use Oracle, SQL Server, MySQL, Sybase or other database system

□ In-house, we use our own program/system (please provide name of program/system)

□ Not in-house, we use other program/system (please provide name of program/system)

14) Which grouping method(s) do you use to develop adjustment factor groups? (please select all that apply)

□ Roadway functional classification

□ Rural/urban designation

□ Geographical stratification

□ Volume groups

□ Cluster analysis

□ Other (please specify)

15) How do you develop adjustment factor groups? (please select all that apply)

□ In-house, we use Microsoft Office Excel and/or Access

□ In-house, we use Oracle, SQL Server, MySQL, Sybase or other database system

□ Not in-house, we use other program/system (please provide name of program/system)

□ In-house, we use our own program/system (please provide name of program/system)

□ Not in-house, we use other program/system (please provide name of program/system)

□ Other (please specify)

16) In the case of cluster analysis, which inputs do you use to develop clusters of permanent sites? (please select all that apply)

Note: Q16 is displayed if the answer selected in Q14 is “Cluster analysis”.

□ 12 monthly factors

□ 84 monthly day-of-week factors

□ 24 hourly factors

□ AADT

□ ADT

□ Geographic coordinates

□ Rural/urban designation

□ Other (please specify)

17) In the case of cluster analysis, how do you determine the final number of clusters?

Note: Q17 is displayed if the answer selected in Q14 is “Cluster analysis”.

18) Do you have adjustment factor groups for lower FCs (6R, 7R, 7U)? If so, which grouping method(s) do you use to develop them? (please select all that apply)

□ No, we do not have

□ Yes, we use roadway functional classification

□ Yes, we use rural/urban designation

□ Yes, we use geographical stratification

□ Yes, we use volume groups

□ Yes, we use cluster analysis

□ Yes, we use other method(s) (please specify)

C. ASSIGNMENT OF SHORT-TERM COUNTS TO ADJUSTMENT FACTOR GROUPS

19) Do you annualize short-term counts by assigning them to adjustment factor groups?

• No
• Yes

20) Which characteristic(s) do you use to assign counts to factor groups? (please select all that apply)

Note: Q20 is displayed if the answer selected in Q19 is “Yes”.

□ No, we do not assign counts to factor groups

□ Roadway functional class

□ Rural/urban designation

□ Region/geography

□ Volume group

□ Time-of-day patterns

□ Other characteristics (please specify)

21) Are there other variables that you have considered using in the assignment process? If so, what are those variables?

Note: Q21 is displayed if the answer selected in Q19 is “Yes”.

22) Which group adjustment factors do you use to annualize short-term traffic volume counts? (please select all that apply)

Note: Q22 is displayed if the answer selected in Q19 is “Yes”.

□ 24 hourly factors

□ 12 monthly factors

□ 84 monthly day-of-week factors

□ 52 weekly factors

□ 365 daily factors

□ Other (please specify below)

23) Which software/system do you use to assign short-term counts to factor groups? (please select all that apply)

Note: Q23 is displayed if the answer selected in Q19 is “Yes”.

□ In-house using Microsoft Office Excel and/or Access

□ In-house using Oracle, SQL Server, MySQL, Sybase or other database

□ In-house, using our own program/system (please provide name of program/system)

□ Not in-house, we use other program/system (please provide name of program/system)

24) Do you factor short-term counts taken on lower FCs (6R, 7R, 7U)? If yes, how? (please select all that apply)

Note: Q24 is displayed if the answer selected in Q19 is “Yes”.

□ No, we do not factor them

□ Yes, we use adjustment factors from higher functional classes

□ Yes, by roadway functional class

□ Yes, by rural/urban designation

□ Yes, by region/geography

□ Yes, by volume group

□ Yes, we use other characteristics (please specify)

25) Do you use any alternative assignment method (e.g., statistical or ML method)?

• No, we do not use
• Yes, we use (please specify)
  

26) Who applies the alternative assignment method stated in the previous question and how? (please select all that apply)

Note: Q26 is displayed if the answer selected in Q19 is “Yes” and the answer selected in Q25 is “Yes, we use (please specify)”.

□ We apply it in-house using a statistical software (please provide name of software)

□ The method is incorporated into our own customized program (please provide name of program)

□ The method is incorporated into our third-party data management system (please provide name of system or provider)

□ Other (please explain)

27) How often do you review or change the assignment of a short-term count site to a factor group?

Note: Q27 is displayed if the answer selected in Q19 is “Yes”.

• Never
• Once every 6-10 years
• Once every 3-5 years
• Once every 1-2 years
• Every time a short-term count is taken
• Other frequency (please specify)
  

D. IMPLEMENTATION PROCESS

28) How likely is each of the following scenarios that involve implementing a new statistical assignment method? (please make a selection for each scenario)

29) Please order (by dragging and dropping each item) the following potential barriers associated with the implementation of a statistical method (1 is the most important and 8 is the least important).

Limited knowledge in statistics and programming

Lack of statistical software

Difficult to interpret and communicate results

Difficult to incorporate method into existing systems

Limited resources (budget and staff)

Limited time

Difficult to gather, process, and incorporate new data variables

Other (please specify)

30) What kind of information and research products (e.g., Guide; windows application; analytics website; code in R, Python, or other language; training material, etc.) would help you select and adopt an assignment method?

31) Can you please provide examples of Guidebooks or other research products that you used in the past to select and implement a new method or process?

This is the end of the survey. Click "Next" to submit your answers. After you click “Next”, you will NOT be able to return to the survey questions.