ancient cities

to shift the role of government from a provider of
public services to a purchaser of public services,
thereby transferring the risks associated with
building and operating the system from the public
to the private sector.
Between 1985 and 2004, nearly 1,000 transportation
projects worldwide worth $424 billion have
been delivered and financed through private–
public partnerships. The United Kingdom and
Australia are among the international leaders,
while such partnerships are also popular in Asia
and South America. By contrast, North America is
a relative latecomer to the application of private–
public partnerships in the transportation megaproject
sector. Despite their growing popularity,
there is mixed evidence about whether private–
public partnerships in the transportation sector
have reduced the cost overruns and performance
shortfalls that typically plague projects delivered
through the conventional model.
Sustainable Transportation
Transportation has key impacts on the environmental,
social, and economic sustainability of cities.
Around the world, transportation planners
have sought to increase the use of the most sustainable
modes of transportation. These are prioritized
as nonmotorized modes such as walking and
cycling, then high-occupancy public-transit services
and automobiles with multiple passengers,
followed by single-occupancy vehicles.
National and local public policy to support
more sustainable urban transportation has taken
four directions. First are policies to encourage
technological advancements in the reliability and
efficiency of transportation systems, as well as
innovations to reduce the total demand for transportation.
The search for and implementation of
cleaner and renewable vehicle fuels has been
encouraged through the enactment of targets for
reductions in permissible vehicle emissions in jurisdictions
such as California and the European
Union. Intelligent transportation systems have
been designed, which use communication technologies
to enhance overall efficiency through realtime
traffic management, public-transit scheduling,
and goods vehicle routing to avoid congestion.
Advancements in digital and communications
technology have been supported by public policies
Transportation Planning
831
to encourage telecommuting and working from
home, which can reduce the need for some travel
journeys.
Second, investments in infrastructure have been
used to make nonmotorized modes of transportation,
public transit, and car pooling more convenient,
reliable, and attractive. These have included
national and local programs to invest in new
public-transit infrastructure, dedicated cycle lanes
and bicycle storage lockers, and high-occupancy
vehicle and bus lanes on existing highways and
arterial roads.
Third, economic and fiscal policies have provided
incentives and disincentives to use different
types of transportation modes. This reflects an
emerging emphasis on balancing increases in the
supply of transportation facilities with the management
of demand for transportation services.
National governments in Europe have employed
high levels of fuel tax to manage demand for road
travel and encourage the ownership of smaller,
more fuel-efficient vehicles. In countries such as
the United Kingdom, registration fees are higher
for more polluting vehicles, providing further
financial incentive to own smaller, less-polluting
vehicles. Conversely, to encourage transit usage,
countries such as Canada and the United States
provide tax deductions for the cost of transit
passes, and many universities provide their students
with discounted transit passes. In some jurisdictions,
sales taxes are not applied to the purchase
of bicycles or their repair, thereby reducing the
cost of using this mode of transportation.
At the urban scale, road pricing schemes have
been developed in cities such as London, with the
revenue used to improve public-transit facilities
and subsidize public-transit fares. Local governments
have also instituted parking management
strategies such as converting free parking to pay
parking to discourage driving to certain areas
within cities.
Fourth, regional and local land use policies have
been devised to support the use of more sustainable
modes of transportation. Many regions have sought
to encourage public-transit use by creating plans to
build high-density residential and commercial
developments surrounding urban rail stations and
by intensifying the population density of existing
communities through in-fill developments. Master
plans for urban development and regeneration