Final Blog prepared by Feng Zhu

Study of Gold Line in Los Angeles Based on GIS

Introduction

(1)Site Analysis

The Gold Line is a light rail system that starts from East Los Angeles, running through downtown of LA until arrive to Pasadena. It opened on June 23th 2003 with a daily ridership projection of 26,000 to 32,000 people per day. Until 2012, the whole line is 19.7 miles long and has 21 stops.

(2)Study Purpose

  • Compare travel behavior changes since the opening of Gold Line.
  • Study the potential layouts of bus routes which connect critical transit nodes along Gold Line and surrounding areas, compare service efficiency of these different routes.

Travel Behavior Change from 2000 to 2010

I selected two variables to measure the change of travel behavior in 2000 and 2010, Commuting Time and Percentage of Auto Dependence(people who travel by driving) respectively, which can be easily acquired and calculated from 2000 SF3 Sample Data and 2010 ACS 5-year estimates provided by U.S. Census Bureau.

Using Select by Location skill, I selected 86 Census Tracts which are within 0.5 miles of the Gold Line Stations and compared the travel behavior data of these selected tracts(few tracts have no data) between 2000 and 2010. It is easily to find that there was a slight decrease of Auto-dependence and commuting time within station surrounding areas since the open of Gold line in 2003.

Find three important transit nodes along Gold Line

Firstly, I made a Service Area Analysis to find areas which are within 15 minutes walking distance(walking speed is 80 meters per minute) from each Gold Line station based on street network of Los Angeles.

Then, I calculated population of each station service area to decide which stations should be strengthened as transit nodes by connecting more bus routes. As a result, I select Union Station, Highland Park and Lake as three transit nodes, which served relatively more  population(136138,51319 and 72710 respectively) and are located evenly along Gold Line.

Calculate Transit Need Index in surrounding areas

Transit Need Index is the extent to which bus service should be provided. Generally speaking, there are four factors which might influence whether the transit need is higher or not, Population Density, Household Income, Percentage of Population Who are Under 18 and Above 65 Years, Percentage of No Car Family. The following figure is the analysis of these four factors.

On the base of converting four factors from feature files to raster files, I reclassified these determinants according to the following rules:

(1)Population Density(Person/Sq miles): <10000=1, 10000~15000=2, 15000~20000=3, 20000~30000=4, >30000=5

(2)Household Income: <30000=4, 30000~50000=3, 50000~100000=2, >100000=1

(3)Percentage of Population Who are Under 18 and Above 65 Years: <15=1, 15~25=2, 25~40=3, >40=4

(4)Percentage of No Car Family: <5=1, 5~15=2, >15=3

After reclassification of these factors, Transit Need Index was calculated by the formula——Transit Need Index=Population Density + Household Income + Percentage of Population Who are Under 18 and Above 65 Years + Percentage of No Car Family.

Through locating five addresses on the areas with higher Transit Need Index, I acquired an original point shape file by Geocoding these addresses.

Give suggestions on bus routes and compare them

Firstly, I made OD Cost Matrix to analyze connection between the five addresses and the three transit nodes.

Secondly, I gave a suggestion of three bus routes which connect the three transit nodes and the five transit need address by using Closest Facility Analysis function in GIS.

Finally, I made a Buffer Analysis of 500 meters with each bus routes and compared the three buffer areas by person/length of route. Obviously, bus route1(from west of LA downtown to Gold Line Union Station) is the transportation corridor with highest service efficiency among the three routes.

Conclusion

(1)After the opening of Gold Line, there was slight decrease of Auto-dependence and commuting time within station surrounding areas from 2000 to 2010.

(2)Three transit nodes along Gold Line, Union Station, Highland Park and Lake should be strengthened by adding more bus routes connecting five surrounding transit need areas with them. Of the three suggested bus routes, the most important one is from west of LA downtown to Union Station.

GIS Skills Used

(1)Inset Map, (2)Point graduated symbol, (3)Creating indices, (4)Attribute sub-sets selection, (5)Boundary sub-sets selection, (6)Geoprocessing, (7)Buffering, (8)Custom shapefile creation, (9)Charts, (10)Hotspot analysis, (11)Geocoding, (12)Network Analysis

Model

Metadata

Geocoding

Data Sources

(1)U.S. Census Bureau:2000 SF3 Sample Data, 2010 ACS 5-year estimates.

(2)Metro Developer

 

Tutorial Assignments: Week3

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