- The numeric values are Gap indices that summarize the overall gap between transit supply (i.e., accessibility) and demand, which is measured by:
$$ \sum_{i=1}^n(\mid ServiceSupply_{i}^{percentile}\mid - \mid ServiceDemand_{i}^{percentile}\mid) \over n $$
- The Gap index ranges from 0 to 1, where a value of 1 represents total inequity.
- The scatterplot shows how the transit service supply is distributed with respect to the transit demand variable.
Atlanta's Transit Equity
Current benchmarks and future possibilities
An interactive tool that compares On-demand Multimodal Transit System (ODMTS) and the conventional transit system in Atlanta in terms of 1) overall accessibility and 2) transit equity/equality
On-Demand Multimodal Transit System
ODMTS connects residents in every corner of Atlanta to high-frequency rail/bus networks by serving their first/last miles via on-demand shuttles.
ODMTS is designed to contribute to improving both the transit accessibility and transit equity in the Atlanta area.
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Transit Accessibility
We measure transit accessibility by how many destinations (e.g., jobs or stores) can be reached from a neighborhood within a given threshold. The threshold can be defined in two ways:
1) The travel time by public transit
2) The ratio of the travel time by public transit to the travel time by driving
Transit Accessbility Map
Conventional Public Transit System
On-demand Multimodal Transit System
Overall Accessibility
Current
ODMTS
%
%
of all residents can commute to work by transit within 45 minutes during morning peak hour
Trip type
Accesibility Type
Proportion of residents who can commute to work by transit within 45 minutes during morning peak hour
less then 5%
5 - 10%
10 - 20%
20 - 30%
30 - 40%
40 - 60%
60 - 80%
more than 80%
Transit Equity
Both equity and equality seek a fair distribution of public resources.
Equity recognizes that each group of people has different circumstances/demands and allocates the resources and opportunities accordingly. ‘Transit service gap’ is employed to capture the transit (in)equity by comparing the supply and demand of transit services at neighborhood level.
Transit Equality
Equality means each group of people is given the same resources or opportunities. Transit (in)equality is measured by the Gini index and Lorenz curve which capture how far the distribution is from equality.
Transit Equity + Equality Map
Conventional Public Transit System
On-demand Multimodal Transit System
Transit Inequality by Level of Demand Help
Current
ODMTS
Low-demand neighborhoods
Mid-demand neighborhoods
High-demand neighborhoods
Transit demand type
Transit demand unit
Trip type
Accesibility Type
Description
The first- and last-mile trip accessibility in public transit trip is one of the most crucial factors affecting whether an individual will choose public transit or not. It is a particularly important issue that needs to be solved in a city like Atlanta, GA, where public transit is not the most favored mode of transportation.
Researchers at Georgia Institute of Technology have developed the On-Demand Multimodal Transit System (ODMTS) that serves first- and last-mile trips via on-demand shuttles. ODMTS is currently at a pilot test stage based on multiple neighborhoods in Atlanta in collaboration with the Metropolitan Atlanta Rapid Transit Authority (MARTA). ODMTS is expected to significantly improve public transit accessibility and, in the long run, reduce auto-dependency in the Atlanta region.
This project showcases the performance of ODMTS in terms of (1) transit accessibility and (2) transit equity+equality, by comparing it with the existing conventional transit system.
Team
- Subhrajit Guhathakurta, Professor
- Pascal Van Hentenryck, Professor
- Uijeong Hwang, Ph.D. Student
- Seung Jae Lieu, Master Student
- Kevin Dalmeijer, Senior Research Associate
- Hongzhao Guan, Ph.D. Student
In collaboration with
