- Veröffentlicht: 08. September 2019
Parsons Transportation Planning Director Hamid Iravani says planners should focus on what has always worked for their cities
Modern Times, a 1936 Charlie Chaplin film, shows its star being fed his lunch by an automated machine. The result is a comical yet effective way of conveying the message that automation only makes a system smarter when the foundation of that system is already smart. Conversely, if the basic framework is inefficient, automation exacerbates the inefficiencies.
Many supply lines feature an economy of scale, meaning the price per unit is reduced as the size of the output increases. For sewerage and water, for instance, a bigger pipe costs less than several smaller pipes. When examining transportation and roadway systems, however, this theory does not hold. In roads, there is a diseconomy of scale, as several narrower roads function much better than one wide road.
A grid system consisting of several interconnected smaller roads provides travellers with many route alternatives from each origin to each destination and evenly distributes traffic on the roads. This diseconomy of scale is illustrated by comparing a grid system to an expressway system when applying a basic smart-city feature, such as one that relays real-time information online, allowing travellers to divert their routes when the downstream segment of the road is congested. While the grid system enables easy access to alternative routes, the expressway system either doesn’t provide alternative routes or only provides occasional access, at much greater distances than the grid system.
The “tragedy of commons” is an economic theory describing how individuals tend to act selfishly by depleting publicly accessible and underpriced or free resources, eventually degrading the public realm in terms of environment, energy consumption, health, and well-being. The theory is usually applied to the effects of pollution in public spaces, but the same principle can be seen in the way cars use public space.
Travelers will continue to use and congest roads unless planning and policies—coupled with suitable design and land use measures—discourage use of private automobiles and provide incentives for public transit and non-motorized transportation modes. Merely applying technology will not produce a smart city. A major prerequisite for a truly smart city is a multimodal system that encourages people to move from private automobiles to public transportation or nonmotorized means of travel. When technologies further promote such a system, they would build on a smart foundation to make a city even smarter.
Developing a smart public transit system takes more than putting rails, trains, or buses on the roads and complementing them with real-time information from smart-city technologies.
More important smart factors include developing the correct urban fabric, along with densities, the appropriate complementary transit feeder and pedestrian network system, and transit-oriented development, to create a place in which alternative transportation modes such as walking, biking, and public transportation are equally viable options to private vehicles, if not preferred choices.
Regardless of how advanced the technologies are and how extensively they’re applied, having a few public transit routes rather than a transit network system, in the absence of an efficient land-use pattern, requires travellers to transfer to different transit lines to move between any given origin and destination, thus discouraging ridership.
The challenge for transportation planners and engineers advocating smart cities is how to build an efficient transportation system without further expanding roads while promoting growth and economic activity. It is encouraging to see many high-density cities moving more people in less time. The key to their success is a smart vision, tackling the demand side of the transportation equation instead of the supply side.
When complemented by advanced technology, like automation and real-time information, a smart strategy such as this is enhanced, resulting in a much smarter system.
The thinking that less accessibility provides better mobility has produced the illusion that because expressways have less access to ingress and egress, they can move traffic without any delay. This concept could be viable if no traveller needed to get on or off expressways, but a significant proportion of traffic on any expressway is there because drivers need to get to the next interchange to get off and go back to access their original destination.
That is not smart.
Moreover, a roadway hierarchy that depends solely on expressways and wide roads will generally collapse if an incident occurs, as most of the expressway will be clogged. Because this system promotes fewer points of ingress and egress, it traps a high magnitude of travellers regardless of the application of smart-city technologies, such as variable message signs.
The term “smart city” is often thought to be synonymous with technology, but the foundation of a smart city is its land-use system. The roadway hierarchy system which depends on expressways and wide roads brings along with it a land-use system that exacerbates an already bad situation—local roads get residential pods surrounding them while commercial areas gather around the expressways. This separates origins, making them further from destinations, thus increasing traffic.
Therefore, land use in such system results in the sprawl effect and segregation of uses. In contrast, an interconnected grid roadway system with dense and narrower roads promotes mixed land use, resulting in origins that are closer to destinations, which is a smart feature for a smart city.
All this is not to say that city transportation planners should be technophobic, only that smart-city planners should also consider all the great community and traditional values that have already functioned in cities so well.
Neo-traditional planning, or “New Urbanism,” has many advocates in the field of advanced and progressive planning. The roadway system favoured by New Urbanism shortens trips, reducing the overall travel demand, and shifts the demand from private vehicles to other modes of transportation. This land-use system is a smart foundation that could be further enhanced by smart-city technology.
Autor(en)/Author(s): Hamid Iravani
Quelle/Source: ME Construction News, 01.09.2019