I would look at the auto per household ratio or auto per person ratio from the CTPP 2006-2008 base data and use that to estimate future autos by TAZ. 

 

I think you will be better off using ratios tied to population or households so that the growth in autos at the TAZ level will keep pace with the growth in households and/or population.  You wouldn’t want a TAZ to have only 10% growth in autos if the household data shows a growth of 50% for that same TAZ.

 

Todd A. Steiss, AICP, GISP
Senior Planner

 

Parsons Brinckerhoff

121 West Trade Street, Suite 1950
Charlotte, NC 28202

Direct: 704-342-5411
Main: 704-342-5401

Mobile: 704-906-7706
Fax: 704-342-8472

Email: steiss@pbworld.com

 

 

 

Hello everyone,

 

We here in Richmond MPO are developing the Socioeconomic data for our Long Range Transportation plan. One of the important components of the data is the total number of automobiles (CTPP Table B111103) by Traffic Analysis Zones (TAZs).  We have in the past used both the CTPP data and the Virginia DMV registration data to calculate autos by TAZs.

 

Here are the problems we are facing this time around. The base year for our socioeconomic data is 2012. CTPP data is a rolling average from 2006-2010. How would one calculate the estimates for the year 2012 taking CTPP 2006-2008 as the base data? Assuming we do a straight line projection, how many years do we need to project the CTPP data to get the estimates for the year 2012?  In other words, do we consider the CTPP data from year 2008 ( which is the mid-year) and project the data by 4 years to get the 2012 estimates or do we take the year 2010 ( which is the end year) and project the data by 2 years to get the 2012 estimates.

 

Any insight would be appreciated.

 

 

Thanks,

Sulabh Aryal

Associate Planner

 

Richmond Regional Planning District Commission

9211 Forest Hill Avenue, Suite 200 Richmond, VA 23235

Phone: 804.323.2033 3 Fax: 804.323.2025

saryal@richmondregional.org  3  www.richmondregional.org