C. Potential Influence of Urban Form on Vehicular Travel
Planners now generally recognize that urban areas can no longer
simply build their way out of costly urban traffic congestion by adding more
highway lane miles.
The cost of maintaining existing highway lane miles has become a serious
burden in most regions of the country.
This suggests that new forms of travel pricing and transportation
infrastructure investment policies are likely to play an important role in shaping U.S. urban systems in
the decades to come.
Complicating the pricing picture, however, are hybrids and other more fuel efficient
vehicles that will likely over the long term reduce the relative costs of driving and thus reduce the financial
incentive to alter high mobility lifestyles. Telecommuting, teleshopping, and other forms of computer
aided travel substitution may also influence future building locations and within unit space designs.
While land use arrangements may account for as much as 50 percent of the variation in travel volumes
across cities, past studies have concluded that land use patterns are difficult to change and may
therefore be able to reduce VMT by only 5 to 12 percent, with or without the assistance of supportive
travel demand management measures.
It is much easier to adapt travel habits than it is to change
urban form. There are numerous other and initially much less costly ways to influence travel. These
include a growing number of travel pricing policies that can only now be implemented as a result of
recent advances in telecommunications systems and their incorporation within traffic monitoring and
With the above comments in mind, any politically feasible solutions based on land use policies
are unlikely to show much impact in the short term. While the payoff may indeed be considerable in
terms of VMT reductions, GHG reductions, and energy savings, it will require a carefully crafted set of
policy instruments and possibly as much as three decades before the effects begin to have major quanti
tative national impacts. A key policy driver may be traffic congestion. To avoid the considerable economic
and environmental effects associated with urban gridlock, as well as reducing GHG and other pollutant
emissions, solutions will need to go well beyond traditional traffic management.
Towards a Climate Friendly