Hi Sulabh, If your scope of the work permits, you may also want to consider the transportation accessibility/network when estimating auto-ownership. This could be a major factor for areas with good transit access or other transportation alternative. Birat Birat Pandey, PE Senior Transportation Engineer/Modeler Baltimore Metropolitan Council Offices @ McHenry Row 1500 Whetstone Way, Suite 300 Baltimore, MD 21230 Ph: 410-732-0500 x1050 bpandey(a)baltometro.org www.baltometro.org *From:* ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces@chrispy.net] *On Behalf Of *Steiss, Todd A. *Sent:* Monday, February 03, 2014 12:31 PM *To:* ctpp-news(a)chrispy.net *Subject:* Re: [CTPP] (no subject) 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, GISPSenior Planner* *Parsons Brinckerhoff* *121 West Trade Street, Suite 1950* *Charlotte, NC 28202* *Direct: 704-342-5411Main: 704-342-5401* *Mobile: 704-906-7706Fax: 704-342-8472* *Email: steiss(a)pbworld.com &lt;steiss(a)pbworld.com&gt;* *From:* ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces@chrispy.net<ctpp-news-bounces@chrispy.net>] *On Behalf Of *Sulabh Aryal *Sent:* Monday, February 03, 2014 11:46 AM *To:* ctpp-news(a)chrispy.net *Subject:* [CTPP] (no subject) 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(a)richmondregional.org 3 www.richmondregional.org ______________________________________________________________________ NOTICE: This communication and any attachments ("this message") may contain confidential information for the sole use of the intended recipient(s). Any unauthorized use, disclosure, viewing, copying, alteration, dissemination or distribution of, or reliance on this message is strictly prohibited. If you have received this message in error, or you are not an authorized recipient, please notify the sender immediately by replying to this message, delete this message and all copies from your e-mail system and destroy any printed copies.