1. Traffic Forecasting with 2016 HCM Methods
Cody Stone, P.E.
June 21, 2018

2. Safety Moment Computer Safety
Traffic Forecasting with 2016 HCM
Safety Moment
Computer Safety
Devote at least five minutes of every hour to a non-computer related task
Stand up while on the phone
Blink your eyes multiple times during computer breaks to avoid eyestrain

3. Agenda What is Traffic Forecasting?
Traffic Forecasting with 2016 HCM
Agenda
What is Traffic Forecasting?
Traffic Forecasting Application to 2016 HCM
2016 HCM Components of Traffic Forecasting
Traffic Forecasting Standard Operating Procedure
Tools for Traffic Forecasting
Questions?
How many people use traffic forecasts on their projects or for their work? Now, how many of you all develop those traffic forecasts?

4. What is Traffic Forecasting?
Traffic Forecasting with 2016 HCM
What is Traffic Forecasting?
Traffic forecasting is the attempt to estimate the number of vehicles that will use a roadway in the future.
Why is it so important? Ultimately, so we do not underdesign (pic on left) or overdesign (pic on right) our roadways. Also, it is important to consider the vehicle type, i.e. number of trucks.

5. Traffic Forecasting Application to 2016 Highway Capacity Manual (HCM)
Traffic Forecasting with 2016 HCM
Traffic Forecasting Application to 2016 Highway Capacity Manual (HCM)
Current or Near-Term Conditions
Operational Analysis
Mid- to Long-Term Implementations
Design Analysis
Long-Range Analyses
Planning and Preliminary Engineering Analysis
Traffic Forecast Application Level
Where is traffic forecasting applicable in the engineering project development? It is mainly focused on analysis of mid and long term improvements. Short term improvements can often be analyzed using existing counts and field observations, while traffic forecasting is essential to making accurate mid and long term analyses.

6. 2016 HCM Components of Traffic Forecasting
Traffic Forecasting with 2016 HCM
2016 HCM Components of Traffic Forecasting
Historical Count Data
Historical counts as far back as you are forecasting forward
Identify growth trends
Travel Demand Model
Changes in demographics and land use
There are several HCM components that we consider when developing traffic forecasts. The first is looking at historical count data. It is important we understand growth in the past and what lead to the current traffic demand. We can identify trends, like if we feel the growth is trending downward due to land use saturation.

7. 2016 HCM Components of Traffic Forecasting
Traffic Forecasting with 2016 HCM
2016 HCM Components of Traffic Forecasting
Planned Development and Land Use
Another important item to consider is planned development and updated land use. At a specific project location, it may be important to incorporate the trip generation of a site plan to capture the local demand. We can also use the area’s travel demand model to anticipate area growth for major corridor projects.
Different purposes to forecast traffic; TIA, corridor analysis, toll analysis, etc.

8. 2016 HCM Components of Traffic Forecasting
Traffic Forecasting with 2016 HCM
2016 HCM Components of Traffic Forecasting
Variations in Demand – Monthly, Daily, and Hourly
Traffic forecasts also consider variation in demand based on hour, day, and month. Seasonal adjustments can sometimes be applied to counts. At certain locations, weekend and event traffic counts and forecasts should be considered. For operational analysis, engineers and planners should carefully consider when a mid-day peak period should be analyzed, in addition to the length of the traffic analysis. This way traffic forecasts can be created that fit the operational analysis scope and overall goals.

9. 2016 HCM Components of Traffic Forecasting
Traffic Forecasting with 2016 HCM
2016 HCM Components of Traffic Forecasting
Uninterrupted Flow vs. Interrupted Flow
Freeway
Urban Streets
“Uninterrupted” is access controlled, mainly freeway facilities. Urban streets have intersections and driveways that interact along a corridor.

10. 2016 HCM Components of Traffic Forecasting
Traffic Forecasting with 2016 HCM
2016 HCM Components of Traffic Forecasting
Demand Volumes NOT Observed Volumes
“Observed volumes may reflect capacity constraints rather than true demand. Demand is usually the desired input to HCM analyses, although it is not always easy to determine.”
–2016 HCM, page 4-2
MAJOR component to traffic forecasting. As most of you are aware, observed counts can be vastly different than demand, especially in a very congested network. Sometimes we reference “induced” demand, when it could have actually been that the forecast used the counts as a baseline. The graph shows how demand can exceed capacity at peak periods, this would result in a flat-lining of traffic counts. Many roads are at capacity and demand diverts to other modes or facilities.

11. 2016 HCM Components of Traffic Forecasting
Traffic Forecasting with 2016 HCM
2016 HCM Components of Traffic Forecasting
What will the traffic forecasts be used for?
Pavement Design
Air and Noise Analysis
Operational Analysis
Toll Analysis
This will help determine if you need 24-hour traffic volumes, percent trucks, K factor, etc. The operational analysis portion is key because sometimes a design-hourly volume is not enough to fully analyze a corridor. It is important to develop the traffic forecast methodology that would consider the peak periods of analysis.

12. Traffic Forecasting Standard Operating Procedure
Traffic Forecasting with 2016 HCM
Traffic Forecasting Standard Operating Procedure
Lessons Learned from Previous Projects
Training
Tools & Innovation
Sometimes easy to say, “well its just growing traffic numbers”…well, it is a bit more involved and can become very complicated on major corridors or with a high level of congestion. I’ll next go over some project development tools that can be used on traffic forecasts.
Implement Corridor Analysis SOP
Schedule
Multi-disciplinary/practice Collaboration
Multiple types of corridors

13. Traffic Forecasting Standard Operating Procedure
Traffic Forecasting with 2016 HCM
Traffic Forecasting Standard Operating Procedure
TPP has a well defined process and we are familiar with its details, the data TPP uses, and common mistakes made by those new to the process.

14. Traffic Forecasting Standard Operating Procedure
Traffic Forecasting with 2016 HCM
Traffic Forecasting Standard Operating Procedure
Important components to project delivery are following flow of tasks and having set QC points for review.

15. Tools for Traffic Forecasting
Traffic Forecasting with 2016 HCM
Tools for Traffic Forecasting
SharePoint Excel
List of Tools
GIS
Sharepoint with Excel
Diversion and Adjustments
Line Diagram Layout and Set-up
GIS
Diversions/Adjustments
Diversions
Lets go over some of the cool tools. Simple things that avoid a headache.
CAD Import
Line Diagrams

16. GIS Standard GIS TxDOT Statewide Planning Map
Traffic Forecasting with 2016 HCM
GIS
Standard GIS
TxDOT Statewide Planning Map
Show type of TxDOT counts used from Database Management Systems
Project Location or Limits Line
Count Locations
Easy to read maps showing where the data is from and what we are using.

17. MS Teams collaboration suite
Traffic Forecasting with 2016 HCM
SharePoint Excel
MS Teams collaboration suite
Integrates with SharePoint, OneNote, Skype for Business
Access to Excel Online
Allows multiple people to access and edit file simultaneously
Avoid restriction of 1 person working at a time
Tight project deadline
Numerous tasks that could be performed simultaneously

18. Diversions/Adjustments
Traffic Forecasting with 2016 HCM
Diversions/Adjustments
“The accuracy of the performance evaluation may be adversely affected if volumes are not balanced.”
-2016 HCM, Page 18-25
Can be the biggest headache in traffic forecasts – difficult to develop consistent set of volumes.
New roads and manual diversions can be complicated and difficult. Sometimes people prefer to do this the old fashion way.

19. Diversions/Adjustments
Traffic Forecasting with 2016 HCM
Diversions/Adjustments
Excel Method
Flexible
Minimizes calculation errors
Enhances efficiency by linking to other sheets
But setting up in Excel allows any updates if assumptions or preferences change.

20. GIS Line Diagrams Straight Line Analysis Complete Corridor Analysis
Traffic Forecasting with 2016 HCM
GIS
Line Diagrams
Straight Line Analysis
Complete Corridor Analysis

21. CAD Import Traffic Forecasting with 2016 HCM
Setting up an import so that you don’t have someone entering numbers in for a week straight.

22. Questions?
Cody Stone, P.E.
Thank You!