[sustran] Re: Slow transport?

[Todd Alexander Litman]

Your question raises several related issues:

First is the distinction between "mobility" and "accessibility" 
(http://www.vtpi.org/access.pdf ). Most current transport planning 
uses indicators that reflect mobility, and so inherently favor higher 
speed modes over lower speed modes, and mobility over accessibility. 
For example, transportation engineers often use estimates of vehicle 
traffic delays and roadway level-of-service (LOS) ratings to identify 
where transportation improvements are needed, which justifies 
widening roadways, even if this reduces access by walking and 
cycling, and stimulates sprawled land use patterns, which increases 
the distance that people must travel to reach destinations. Many 
planning professionals now realize that improving land use 
accessibility (for example, by creating more compact, walkable 
communities) is a legitimate way to improve transportation.

In addition, many planners now recognize the effects of "induced 
travel" and a "constant travel time budget" 
(http://www.vtpi.org/gentraf.pdf ) which imply that efforts to 
increase travel speeds do not really reduce congestion or save travel 
time over the long run, they stimulate more mobility and sprawl. This 
may provide direct benefits to users (the people who travel more and 
live in more distant communities) but imposes numerous external costs 
on soceity, including increased traffic congestion, accident risk, 
land use impacts, energy consumption and sprawl 
(http://www.vtpi.org/landuse.pdf ).

Since travel time costs are a major factor in transportation project 
evaluation, it is important that it be correctly valued 
(http://www.vtpi.org/tca/tca0502.pdf ). Unfortunately, most current 
travel models are biased in ways that undervalue walking, cycling and 
public transit service quality improvements, and overvalue highway 
capacity expansion, because they ignore the higher cost that should 
be assigned to unpleasant conditions (walking on busy roads that lack 
sidewalks, crossing busy highways, waiting for a bus alongside a busy 
roadway, traveling by crowded bus or train), which should give 
priority to improvements to these modes 
(http://www.vtpi.org/quality.pdf ). Described differently, more 
objective transportation investment models would be willing to spend 
as much to reduce per-minute travel time costs (for example, by 
reducing bus crowding or improving pedestrian conditions) as is spent 
to reduce the minutes spent in travel (for example, by widening roadways).

In addition, current planning practices tend to undercount total 
walking and cycling activity, and ignore or undervalue many of the 
benefits of shifts from motorized to nonmotorized modes 
(http://www.vtpi.org/walkability.pdf ). Fortunately, many people 
within the transportation planning profession are realizing these 
points. For example, many recent issues of the Institute of 
Transportation Engineers Journal 
(http://www.ite.org/itejournal/index.asp ) have been filled with 
articles concerning pedestrian and transit improvement techniques.


Best wishes,
-Todd Litman



and the implications of a fixed travel time budget.

At 07:14 AM 12/31/2007, Carlosfelipe Pardo wrote:
>Hi,
>
>Does anyone know of any research or theory of urban planning or
>transport planning that takes *speed* as a factor to be taken into
>account? I have been searching for this and haven't found anything.
>I thought about this because I've seen that transport planning normally
>takes land use, modes, infrastructure and other factors into account,
>but it doesn't seem to take speed as a component in its own right.
>
>The only explicit reference I could find was Le Corbusier, who
>emphasizes the role of high speeds in a city, and plans around those
>high speeds (elevated highways, etc). Should we think about slowness as
>a *positive* characteristic of transport? Should we propose slow
>transport as one solution to the problem?
>
>I think slowness should be promoted not just for reasons of road safety
>but for issues of sustainability in shorter distances traveled (slower
>speeds means longer travel times, so people would try to reduce their
>travel distances) and thus lower energy expenditures and emissions. Of
>course, this would need us to think about strategies to reduce speeds,
>which would include what we're normally promoting (bicycles, pedestrian
>areas, 30km/h speed limits, etc).
>
>Comments on this are most welcome.
>
>Ah, and happy new year!
>
>Best regards,
>
>--
>Carlosfelipe Pardo
>
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Sincerely,
Todd Alexander Litman
Victoria Transport Policy Institute (www.vtpi.org)
litman at vtpi.org
Phone & Fax 250-360-1560
1250 Rudlin Street, Victoria, BC, V8V 3R7, CANADA
"Efficiency - Equity - Clarity"