For this week’s post I’ve used the 2012-2013 Household Travel Survey which is conducted by Delaware Valley Regional Planning Commission (DVRPC) to create maps that visualize travel patterns in the Greater Philadelphia region. DVRPC, in its nine-county planning area, covers the counties of Bucks, Chester, Delaware, Montgomery, and Philadelphia in Southeastern Pennsylvania; along with Burlington, Camden, Gloucester, and Mercer in Southern New Jersey. Randomly selected participants used a travel diary to record how, where, and when they traveled for a single day for the survey. For each household member, information on travel mode, trip purpose, destination and time of day was recorded, along with demographic data such as age, gender, vehicle availability, and student and employment status. This data plays a crucial role in understanding the travel patterns throughout the greater Philadelphia region. The full Household Travel Survey data can be accessed here. In this post, I have displayed the survey data in a spatial format, making it easier for people to understand and explore.
The most recent Household Travel Survey was conducted between 2012 and 2013. The full survey dataset contains more than 80,000 trips, but the dataset used in my analysis only filters the data with valid origin and destination Transit Analysis Zones (TAZs), and departure time. There are more than 54,000 trips visualized in this map. Each line on the map represents one trip from its origin TAZ to its destination TAZ.
Travel Flows in Greater Philadelphia
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Source: DVRPC HTS data download page (2012, 2013), Econsult Solutions (2017), Carto(2017)
From this map, we can clearly see Philadelphia’s significant attraction in the region. According to DVRPC’s report, 34.5% of the employees working in Philadelphia reside in other counties. Philadelphia, especially Center City, has a significant concentration of travel activities. Aside from Philadelphia, places like Trenton, Cherry Hill, Abington, Bensalem, Norristown and King of Prussia also show highly active travel patterns on the map.
There were more trips that began at 7:00 AM and 8:00 AM (16% of total)[1], and 3:00 PM to 5:00 PM (26% of total), which are typically known as rush hours. The first figure on the right side of the map shows the number of trips by depart time in a 24 hour period. Each bar in the figure represents one hour, starting from 0:00 to 23:00, where you are allowed to select the time (or a range of time) for which you would like to visualize the trips.
In this dataset, 80% of the trips were made by vehicles, 11% were made by walking or by biking, and 6% were made by transit. Most of the trips made by walking, biking or transit happened in Philadelphia, especially within Center City (click on the icon on the right to symbolize the trips by mode different travel mode, or click on the mode category to show only trips with the selected mode on the map).
The average travel time of all the trips within the region is 20.66 minutes, with an average travel distance of 6.9 miles. Trips starting at 6:00 AM have the longest travel time, which is 30.53 minutes. Trips starting at 5:00 PM have the longest travel distance, which is 12.19 miles (select trips by depart time in the first table to check average travel time and average travel distance, and other statistics by different times of the day).
The last figure on the left side allows you to visualize the trips to, from, or within Center City [2], and check the statistics for each type of trip. We can see that more trips from other areas to Center City happened in the morning rush hours, and more trips from Center City to other areas happened in the afternoon rush hours. The average travel time of trips from other areas to Center City, and from Center City to other areas was both higher than the average travel time in the region, but with a longer travel distance than the region’s average. Most of these two kinds or trips were made by private cars. Most of the trips within Center City were made by walking or biking.
The animated maps below show the dynamics of origin and destination clusters in a 24 hour period. You will see some interesting findings by comparing the origin and destination clusters of the same time of the day. For example, by looking at the origin and destination clusters at 8:00 AM or 9:00 AM in Norristown, you’ll find there are both origin and destination clusters, but the origin cluster is slightly more significant, which indicates that Norristown is more of an origin than a destination. According to OntheMap, 93% of the residents in Norristown work outside of the borough, and 90% of the employers in Norristown commutes from other places for work.
Trip Origin Clusters Within a 24 Hour Period
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Source: DVRPC HTS data download page (2012, 2013), Econsult Solutions (2017), Carto(2017)
Trip Destination Clusters Within a 24 Hour Period
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Source: DVRPC HTS data download page (2012, 2013), Econsult Solutions (2017), Carto(2017)
Feel free to play with the maps and let us know your findings and insights on travel patterns in the Philadelphia region!
[1] Because we’re using a different subset of data for mapping the survey data, the statistics calculated in this post might be slightly different from the results in the official DVRPC Household Survey Report. The full report can be accessed here:
[2] Center City as referred to in the post is the area between Girard Avenue and Tasker Street, which is defined as Greater Center City by Center City District.
Jing Liu is a GIS Research Analyst at Econsult Solutions. She specializes in spatial analysis, quantitative analysis, and data visualization. Prior to joining ESI in 2016, Jing received her Master’s in City Planning and Urban Spatial Analytics from the University of Pennsylvania