| Journey to Work Trips along Eastbound U.S. 50 from the City of Sacramento | |
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Author Melinda Rogers American River College, GIS 350: Data Acquisition in GIS; Spring 2008 | |
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Abstract A better, faster commute through the City of Sacramento is essential to the needs of daily commuters. One potential solution would be to add carpool or High Occupancy Vehicle (HOV) lanes to the freeway routes that go through the City limits. However, convincing the City Council there is a need to provide HOV lanes through the City of Sacramento is easier said than done. | |
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Introduction In 2006, management would be meeting with the City of Sacramento Council Members to push for an HOV lane to be added to US 50. In the presentation, it was necessary to convince the City Council Members there were several Journey to Work trips made on this leg of US 50 directly from their individual Districts. The bulk of the presentation would include Journey to Work Trips eastbound on US 50 from the I-5/US 50 Interchange. More specifically, the eastbound trips would include trips made by the voters from each of the eight Council Districts. If the presentation is successful, the Council Members will allocate funding for installation of HOV lanes. | |
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Background When transportation funds are funneled through the political process, 75% of the funds go to local governments (i.e. cities, counties, transit, etc.) and the other 25% go to the State Department of Transportation (Caltrans.) In order to maintain highway systems through these individual jurisdictions, Caltrans must request funding from the respective local government so they can adequately fund projects. If the local jurisdiction is not willing to provide the funds, the proposed project may not be feasible. The City of Sacramento may not necessarily be fond of HOV lanes and may not believe there are enough Journey to Work trips that go outside of the city limits to warrant the lanes. In this presentation, our goal is to provide statistical data from the U.S. Census indicative of the Journey to Work trips specifically from the eight Council Districts. | |
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Methods The first step was to identify how far East our data would represent. Basically, how far do the voters from these individual Council Districts drive from their homes within the city limits to their work destination. Our furthest destination was established to be El Dorado Hills/Cameron Park in El Dorado County. I needed to gather Journey to Work data from Sacramento to various destinations between the City of Sacramento and El Dorado Hills/Cameron Park.I used the Census Transportation Planning Package 2000 (CTPP2000) data, which is derived from the 2000 U.S. Census, to identify Journey to Work trips. This data was specifically tabulated to meet the needs of Transportation Planners. The CTPP2000 is a series of tabulations for various levels of geography, including state, county, place, census tract and block group, and traffic analysis zone (TAZ). The tables in the CTPP relate social and demographic characteristics of persons, households, and workers to the journey-to-work characteristics, such as travel time and travel mode to work. (CTPP 2000) In our presentation, the most important of these characteristics being the Journey to Work data. There are three parts to the CTPP2000. Parts 1 and 2 allow the end user to use only one geographic location for analysis, Part 3 is specifically designed for selecting two geographic locations so I could include both home and work destinations. Using Part 3, I was able to search by using the ‘BOTH from RESIDENCE and to WORKPLACE’ option in order to identify the City of Sacramento as the residence variable and various urban areas East of the City of Sacramento as the workplace variables. Through this process, I was able to identify 6,143 records. The records identified 96 tracts from the city limits of Sacramento and their individual Workplace destinations within the define parameters. In identifying census data, you must understand the numeric code assigned to each record. The codes are as follows: State of California = 06 County of Sacramento = 067 County of El Dorado = 017 Census Tract = remaining digits, i.e. 0002.00 Following is an example of the tabular data pulled from the CTPP2000 data identifying how many trips originate from the census tracts in the City of Sacramento with a destination East of Sacramento to El Dorado Hills/Cameron Park. | |
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Next it was necessary to determine how the Census Tracts fit into the Council Districts. For the most part, the Census Tracts were easily separated within the boundaries of the Council Districts, however, there were a few along the boundaries where I needed to estimate how much of the Census Tract was in each Council District. By using a dataset acquired by a contact at the City of Sacramento, I was able to place the Districts layer over the census tract data layer to get a better idea of where the census tracts fit into the Districts. Where the census tracts were split between two or more Districts, I had to determine how much of a percentage of the census tract was in each Council District. | |
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Analysis My analysis summarizes the eastbound Journey to Work trips as well as the westbound to Home trips.
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In analyzing the numbers, manually, I was able to determine how many Journey to Work trips came from each Sacramento City Council District heading eastbound on US50. | |
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Analyzing the data coming westbound US50 from El Dorado Hills/Cameron Park and each urban area in between to Sacramento, I was able to determine a rough number of people traveling home to Sacramento. Please note the analysis to Sacramento was less detailed than the analysis from Sacramento as I was not able to determine exactly where these trips were headed. Sacramento could mean the City of Sacramento and any unincorporated area in the Sacramento region with a mailing address of ‘Sacramento.’ | |
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In order to determine my numbers were close to actual true data, I compared them to a set of data found at Sacramento Area Council of Governments (SACOG) employment data provided on their website. | |
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Conclusions The data gathered to create the two preceding Inbound and Outbound maps show there are several Journey to Work trips coming from the City of Sacramento Council Districts going eastbound on US50. Also, there are several Inbound to home trips coming toward and through the City of Sacramento. My analysis shows there is a potential need for HOV lanes on the US50 corridor through the City of Sacramento. Not only would an HOV lanes potentially alleviate commuter traffic, it would also help those who are travelling through this busy web of highway systems toward other destinations such as the Sacramento Airport and Bay Area cities.
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References Census Transportation Planning Package 2000, CTPP2000, http://www.fhwa.dot.gov/ctpp/ California Department of Transportation, Caltrans, Melinda Rogers, Personal Work Experience Sacramento Area Council of Governments, SACOG, http://www.sacog.org/demographics/employment/ U.S. Census Bureau, U.S. Department of Commerce Economics and Statistics Administration, http://www2.census.gov/geo/sd2007_rev/st06_california/maps/ | |