Chapter 12: UrbanTransportation Policy
“Everything in life is somewhere else, and you get there in a car.”
E. B. White, One Man’s Meat, (NY: Harper & bros, 1942).
Related Concepts
Infrastructure
Public Good
Natural Monopoly
Traffic Congestion
Traffic vs. Traffic Flow
Added autos reduce stopping distance and limit one’s ability to enter thehighway or switch lanes.
Without an accident or bottleneck, complete gridlock is very unlikely.
Externalities from Congestion
As a road approaches capacity, each new auto slows all cars on thehighway, producing external costs and a deadweight loss from overuse.
Externalities from congestion include the time and money costs of delay, anincreased risk of accidents, and noise and air pollution.
Table 12-1: Sources of Traffic Congestion
Source of Congestion
Percent of Total
Bottlenecks
40%
Traffic Incidents
25%
Bad Weather
15%
Work Zones
10%
Poor Signal Timing
5%
Special Events/Other
5%
Source: Federal Highway Administration
Table 12-2: Congestion Costs per Auto
*The ratio of rush hour travel time to free-flow travel time
Source: Schrank, et. al, 2012
Congestion Measures
per commuting driver
1982
2000
2005
2011
Yearly delay (hours)
16
39
43
38
Travel time index*
1.07
1.19
1.23
1.18
Wasted fuel (gallons)
8
19
23
19
CO2 per auto (lbs)
160
388
451
380
Congestion cost (2011$)
$342
$795
$810
$818
Highway Safety
Total fatalities have fallen despite greater miles traveled.
Policy Alternatives
New Highway Construction
Highway construction increases capacity, but also leads to “tripleconvergence” and relatively little long term effect on congestion.
Example: Boston’ “Big Dig”
Boston’s Central Artery project (known as the “Big Dig”) involved replacingan elevated 6 lane highway with an underground multi-layer 8 to 10 laneroute directly beneath the original road.
The Big Dig project was under construction from 1991 to 2007. The total costfor the Big Dig project totaled approximately $15 billion, or nearly $2 billionper mile.
The effect of the Big Dig project on congestion is unclear. The Tom-TomCongestion Index says Boston had only a 10% average highway delay, butthe Federal Highway Administration ranks Boston as the 6th mostcongested city in the U.S. in 2013 with a 25% average peak period delay.
Congestion Fees
Fees or taxes for rush hour driving such as in Singapore or through HOTlanes reduce rush hour demand while not directly affecting off peak travel.
Urban Mass Transit
MARTA rail, 2004 and 2015.
Proposed plans to add a ring rail line toAtlanta’s MARTA rail system are still beingconsidered, but have not yet beencompleted
A light rail loop route is possible in the future
MARTA expansion concepts
Update on MARTA
As of 2014, MARTA has divided its expansion plans into a number of smallerinitiatives, (http://itsmarta.com/expansion-projects.aspx) most of which arestill in the evaluation stage.
As of 2015, MARTA’s heavy rail map is identical to the 2004 mapreproduced earlier.
Conclusion
The primary lesson of this chapter is that some policy problems have a largenumber of possible solutions. The problem of traffic congestion can beimproved temporarily or permanently by increasing the supply of highwaylanes, decreasing rush hour demand through fees and taxes, encouragingcar-pooling through regulations, increasing the availability of substitutes forthe automobile by subway or express bus investments, and lowering thecost of these alternatives through subsidies.