Commuting Using Public Transportation

1
Commuting Using Public Transportation

• Matthew E. Kahn
• Tufts University

2
Percent Commuting Using Public Transit from 1970
to 2000
3
Boston Public Transit Commuting Shares
4
1990 Percentage Using Public Transit to Commute
5
The Slow Bus

• Glaeser, Kahn and Rappaport (2005) investigate
  commute times in minutes by transit mode
• BUS Commute 19.3 3.3miles to work
• CAR Commute 4.3 2.1miles to work
• A 5 mile commute would take 35 minutes by bus and
  15 minutes by car

6
The Challenge for Public Transit

• More people are living and working in the suburbs
• As wages rise, our value of time increases

7
Possibilities for Public Transit

• Environmental benefits if people commute using
  this mode
• Falling urban crime
• Improved center city amenities
• Aging population
• Immigrant population

8
Rail Line Expansions

• Sixteen different cities (including Boston) have
  made major investments in public transit
• These investments have cost billions of dollars,
  possible bus deterioration
• What do we know about the benefits of such
  investments?
• My research has focused on the entire nations
  experience since 1970
• Example of the Red Line Extension

9
Alternative Research Designs

• Macro Transportation research would evaluate
  the effectiveness of new rail transit investments
  by doing a before/after comparison at the city
  level
• As a micro economist, Ive sought to
  disaggregate and look at community level census
  tract data

10
Extend Red Line to Davis Square and this Census
Tract is now Close to Rail Transit
Census Tract
Davis Square
Harvard Square
11
For such Treated Tracts

• How does
• Public Transit Use Change by Decade?
• Tract Demographics?
• Tract home prices?
• To answer this question requires spatially
  merging two types of data
• 1. Census data on how communities channge over
  time, 2. transit data on what rail lines are
  built where in what year

12
Percent Commuting Using Public Transit
13
Percent of Adults who are College Graduates
14
Percent of Residents who are Black
15
Log of Average Home Price
16
Public Transit Use Shares in Boston
17
Why?

• Close to the Central Business District, when new
  rail is built bus takers substitute to rail
• Their quality of life improves but public transit
  numbers do not improve
• Further from the CBD, new rail access leads to
  car to rail substitution

18
Tradeoffs for expansions of Park and Ride Stations

• The evidence suggests that they do foster
  increased use of public transit
• BUT, unlike walk and ride stations, there is
  little evidence that they improve the local
  communitys quality of life
• Suggests compensating local communities for
  accepting a park and ride station?