Energy Efficiency: Thinking beyond Building Envelopes
Mapping Pedestrian Connectivity Gaps in Atlanta
1. Mapping Pedestrian
Connectivity Gaps in
Atlanta
Carly Queen
Master’s Degree Candidate, Civil Engineering / City & Regional Planning
Georgia Institute of Technology
Atlanta Studies Symposium
May 6, 2015
2. Agenda
• Defining Pedestrian Connectivity Gaps
• Data Sources and Assumptions
• Identifying and Mapping Gaps
• “Gap Analysis”
• Findings and Results
• Recommendations
• Future Research
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3. What Are Pedestrian Barriers?
• Interstates / Expressways / Freeways
• Railroad and MARTA Lines
• Rivers / Lakes / Streams
• Large Buildings / Industrial Sites
• Sprawling Areas with No Through Connectivity
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4. Data Sources and Assumptions
• Data from Atlanta Regional Commission
• Population and Employment Density
• Rivers, Lakes, Ponds, Streams
• Roads, Highways, Railroads, Bike Infrastructure
• Parks, Activity Centers, Elevation
• Assumptions
• Rail Lines are Barriers
• Waterways are Barriers
• Interstates are Barriers
• Streets Allow Pedestrians
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8. Findings / Results
• More than 500 gaps with area > 10 acres mapped!
• Top 25 and Top 10 for Area and Perimeter
• Gaps with High Perimeter to Area Ratios
• Gaps in and around Activity Centers
• Fewest Gaps in Urbanized Areas
• Largest Gaps at:
• Airport
• Interstate Interchanges
• Rail Yards
• Chattahoochee River
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19. Recommendations / Conclusions
• Most of Atlanta is not easily accessed by walking
• Plan street network and road design to provide better
connectivity for pedestrians and cyclists
• Grid system and complete streets
• Active mode networks to accommodate all users
• Safe bicycle and pedestrian crossings
• Implement viable solutions to pedestrian barriers
• Multi-use paths
• Bridges and tunnels
• Parks and traversable green spaces
• Improved and expanded transit systems
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20. Future Research
• Refine methodology, automate processes
• Incorporate sidewalk network and condition, as
well as tree canopy, fences, etc. into study
• More detailed analysis of each gap
• Analysis of gaps and passageways as they relate to
traffic congestion and travel patterns
• More in-depth analysis of terrain for cliffs and other
physical barriers in the landscape
• Investigate and implement solutions as appropriate
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21. Thank you!
Any questions?
Carly Queen
Dual Master’s Degree Student
Civil Engineering
City and Regional Planning
Georgia Institute of Technology
carlyqueen@gatech.edu
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Notes de l'éditeur
Barriers = Pedestrians Cannot Pass
Major Mobility Corridors
Waterbodies
Large / Suburban Style Developments
Pedestrian Connectivity Gaps = Areas where pedestrians cannot pass through, but must walk around
Methodology – First considered elevation
Green = low-lying areas
Red = higher elevations
Not a great deal of elevation change
Slope Tool in ArcGIS to Find Slope of Land in Degrees
Few areas with significant slope, so this was NOT considered as a barrier in the study
Further analysis could lead to identification of many additional gaps
One example of the various phases of analysis that I went through involved looking at road crossings of water bodies.
The intersect tool was used to highlight road segments that cross water bodies in green, which allowed me to clearly see where pedestrians could and could not cross rivers and streams as I was drawing gaps.
Through visual inspection of satellite imagery and various phases of GIS data analysis, more than 500 pedestrian connectivity gaps of 10 acres or greater were identified and mapped. The gaps were then analyzed to identify the top 25 and top 10 in terms of area and perimeter. Of particular interest for this study were gaps with high perimeter to area ratios and those lying in and around activity centers. Generally speaking Atlanta’s urban core had fewer gaps than the outer periphery. The largest gaps overall were the airport, several interchanges, rail yards, and the Chattahoochee River.
Closer look
Although most of the central city appears to be fairly gap-free, I-20 and the downtown connector, as well as rail lines, still divide urban areas.
Large pedestrian barriers often divided high-wealth communities from low-wealth communities.
Many of the outlying neighborhoods in the north follow a suburban development pattern that does not support walking.
Once the gaps were drawn, they could be considered relative to employment and population densities.
Note that in this case the largest pedestrian connectivity gap (the airport) is also one of the largest employment centers.
Also major pedestrian connectivity gaps around Emory and the CDC, as well as more northern employment centers.
This map shows population density, as well as the Top 10 gaps by area.
Airport is #1 with nearly 5,000 acres.
Cluster of large gaps along the southern portion of Perimeter Highway and the northeastern and northwestern corners of the city.
Fortunately many of these areas are sparsely populated.
Considering perimeter gives a slightly different perspective, although many of these gaps were also on the previous slide.
Again, a major cluster along the southern portion of Perimeter Highway.
Also see a cluster in the northwest, mostly along the Chattahoochee River, but also including the enormous rail yards.
I also analyzed the ratio of perimeter to area for each gap to identify those that look something like this: long and skinny
These areas could greatly benefit from relatively minor investments in pedestrian infrastructure to cross interstates and other barriers that are fairly small in one direction, but larger in another. These are places where we could begin to reconnect communities that have long been divided.
An even bigger priority in my opinion would be to address the gaps that lie in and around Atlanta’s activity centers.
Shown here in light purple, these are areas where people should be expected and encouraged to walk or bike, to minimize traffic congestion and its impacts on surrounding communities. Let’s take a closer look at a few of these.
In the central core the barriers between communities and the impacts of development patterns are evident.
Purple = activity centers, Blue = BeltLine corridor, Pink = multi-use path
Although there are several walkable areas with completely gridded street networks, even these communities are divided up by interstates and rail lines.
Now compare the wealthier, more connected residential areas in the east to the scattered residential areas to the west. Commercial and industrial areas in the west may also suffer from a lack of accessibility.
At the northern end of the BeltLine corridor, Lindbergh Center and “Buckhead South” are almost completely inaccessible to pedestrians.
Lindbergh Center is billed as one of Atlanta’s first TODs, but transit and driving are the primary access modes (rather than active modes).
Buckhead South is primarily accessible via automobile, bus, and walking or biking along Peachtree Road (a 6-lane highway with limited crossings).
The new home of the Braves stadium doesn’t hold much promise for pedestrians either. The major interchange that lies at its heart is likely to deter people from walking. Traffic congestion may get far worse here, as people feel the need to drive even within the Cumberland CID.
Here’s the big one – Hartsfield-Jackson International Airport, which I believe is the busiest airport by passenger volumes in the U.S.
Accessible by MARTA rail from College Park and north. How would you get there from Clayton County or Hapeville?
For those with limited vehicle access, transportation could be a barrier to employment here. Walking or biking are not viable options, so airport employees would have to get a ride to and from work each day or pay at least $4 per day to park.
The ideas that have been floating around for years about capping interstates to install parks and greenspace are brilliant. If done correctly these could help to provide numerous community benefits. Let’s pursue this and other ideas to reconnect our city and make it whole again!
It isn’t the focus of this research, but many of the pedestrian connectivity gaps are also gaps in automobile connectivity. We might be able to mitigate congestion by working to eliminate these barriers and any bottlenecks that are attributable to a lack of route options for cars.
