A New Direction for Transport Planning
Realities of Today
The Car and the City
The impact of private vehicles on the urban fabric is undoubtedly a well-known issue. The space that through the years has been dedicated to the car has often modeled the new form of growing settlements or profoundly affected historic city centres.
During the first years since the appearance of the car, the social innovations introduced by Henry Ford—minimum wage, shorter working hours and affordable cars—made it possible for thousands of workers to become car owners and commuters.
Considering the generally poor living conditions of the overcrowded cities at the beginning of the century, especially in the United States and in the UK, the car offered the simplest—in that it is individual—solution towards moving away from these congested environments of bad housing1. Hence the subsequent generation of the low density suburbs.
A Typical Example of Knowledge Silos—Traffic Engineering
Due to the incredibly steep growth of vehicle ownership early in the last century in the States and after the war in Europe, a car-centered urban vision grew and strengthened, flourishing in the 60s with the Modernist vision. Roads and buildings weren't meant to communicate anymore, their relationship was broken and so was any inter-disciplinary approach to urban planning. What Marshall describes as the schism of Modernism2, produced the consequent schism of professions.
The identification of a "traffic flow" as a discipline led to the birth of a very specific professional figure to whom the study and design of the "movement channel" was entirely assigned: the traffic engineer.
The hyper-specialisation of this professional figure, together with an inward looking approach based on quantitative issues alone, generated detrimental urban interventions that are now dotted throughout cities around the world3.
Traffic engineering is possibly the clearest example of a "knowledge silo": the simplification of vehicular movement into mathematical simulations (often generating spectacular failures) and the inability to establish a dialogue with other disciplines has proven to be a major issue when facing complex problems typical of the contemporary world.
The growing importance of sustainability issues has brought up a set of problems of unprecedented complexity and interdependency (on this topic see this HDL link).
A Car-centred Approach
The approach that has characterised transport engineering since the 60s in Europe, as in the rest of the western world, has been centered on giving maximum capacity to the road network, in order to respond to the continuous growth of traffic. More and more urban space has been given to the automobile.
Moreover, because the car is a land-hungry transport system as well as being energy intensive and an emitter of pollutants, the "Faustian bargain" evoked by John Whitelegg4—the willingness to give away urban quality in order to ensure as much vehicular movement as possible—is evident in most cities worldwide. Some western cities have witnessed the expansion of space dedicated to the car on the road network until very recently, as well as the construction of major urban motorways in dense city centers. The space given to the automobile in the new suburbs has generated diffuse urban patterns with a major role played by car movement and parking.
Without lingering on the issue of whether the car has determined the demise of urban public life or on the contrary the car has given a technological answer to desires already embedded within society5, it appears clear that the overall result of the car-centred approach has proven disastrous to urban quality.
Towards Reducing Infrastructure
Peak Traffic in the Western World
Since the first Ford Model T, traffic and car ownership (and more precisely the mileage travelled by car) have constantly been growing in the western cities and are now expected to grow very steeply in the emerging countries, where the car industry is focusing most of its sales in the upcoming years.
Nevertheless, we are recently witnessing (or becoming aware of, since some first signals had already emerged in the 90s6) a decrement in car usage. It has been shown7 that vehicle miles travelled (VMT) have finally peaked in the western world and the inversion of this trend is related to a complex combination of causes. The worldwide economic crisis with the associated rise in fuel prices is the unifying element underlying technological and social factors: limited travel time budget, diffusion of transit-centred policies and a re-urbanization bias both for young and older people who are less and less attracted by the car8.
The Real-time Revolution
Changes in social habits that directly or indirectly influence car usage are already taking place.
The development of ICT as a general trend within our society now allows thinking of integrated management systems, where mobility-related data is collected in real time and analyzed in order to improve service efficiency (see IBM Smarter City site).
Examples could apply to the management of a public transport network, of a multimodal mobility network, of a car park management system at the city scale or the real-time update of a dynamic pricing policy.
The great potential of information technology as an instrument of optimisation is mostly due to the fact that the improvements are both to the managements' and the users' benefit.
Systems that are currently becoming more and more popular—especially among young generations—such us car sharing or bike sharing are supported by and based on this kind of technology. In the framework of the re-urbanisation that has been registered as one of the causes of the peak car phenomenon, these sharing habits can also be read as a progressive separation from the idea of the car as a symbol to posses, returning it to the realm of the instrument to be used.
New Policies for the Car in the City
As cars become tools to use and share rather than objects to desire and possess, it appears clear that a new awareness is emerging when it comes to understanding the impact of the automobile on the city fabric.
In this sense, traffic containment policies such as congestion charges or high hourly rates for car parks in city centres are becoming—in the western world—increasingly accepted by the population, which is therefore starting to internalise the externalities of the car that have traditionally not been associated with a cost.
The introduction of congestion charges, starting from Singapore some 25 years ago and following with Oslo in 1990 and London in 2003, has been shown to be a feasible route; the shift towards a different way of thinking about the presence of the car in the city has proved to be evident even in traditionally car-dominated environment, as shown in a recent referendum on the city in Milan9.
A New Set of Tools
As new policies are being envisaged a progressive shift is happening in the realm of transport planning. One key element is the growing criticism of one of the pillars of the sector: the "predict and provide" methodology.
From back in the late 50s and up to the early 90s, transport planning was about forecasting traffic growth—the demand—and then building a road infrastructure wide enough to accommodate it.
This approach has proved to be—and is now widely recognized10 as—an unsuccessful strategy, causing a faster saturation of the new road, due to the temporary reduction in the level of congestion and consequent attraction of new users. This phenomenon has been largely investigated under the name of "induced traffic"11.
During the 90s planning moved from providing for what was predicted, to preventing the prediction from becoming true12.
The recognition of the fallacies of simply adding road infrastructure as the way out of congestion has determined a major slowdown in new road construction in certain parts of the western world.
In the same logic, there has been increasing criticism of what used to be the pillars of transport planning such as the level of service (LOS) approach13.
The necessity for a holistic understanding of the relation between flows and space is again becoming a priority in the planning field.
A New Way of Doing Things—Towards Reducing Infrastructure
Looking at the road network from this perspective might open up different ways of thinking in long-term planning—do we really need all the major infrastructures that are still planned in cities throughout the world? Or it is maybe now time to stop the construction of new roads and conversely to start eating away at existing infrastructure?
The issue of peak traffic, new policies and real time data processing, as well as the progressive shift in the transport planning field discussed above, are setting the basis for a possible revision of the way we plan cities and road infrastructures, which in the past focused on making them grow constantly, following (and at the same time stimulating14) the rise of car usage.
We are at a change of the tide: in the last decade (and up until very recently) cities have been experiencing a continuous growth in traffic, while it seems now that the use we make of cars has peaked. Therefore we might imagine a different future, a future in which we will progressively readjust and/or remove existing road infrastructure.
A new road network might emerge onto which a low-impact public transport network could be superimposed, along with mobility-on-demand systems to cover the last mile problem15.
It is therefore possible to start shaping the image of a new city, an image different from what we have built and experienced in the last decades.
From Theory to Practice: a New City Looking to the Future
The planning concepts that have been introduced thus far find a practical application in a cutting-edge project in Saudi Arabia: a sustainable city with 180,000 residents based on renewable energy supplies and focused on a future of sustainable mobility. With Foster + Partners leading the group as the master planner, in this project our know-how summed up with that of many other players, creating a multi-disciplinary team that covered several areas of expertise.
The masterplan is located in proximity of the capital of Saudi Arabia, on a major motorway which links the project area to Riyadh and other parts of the Kingdom. It is spread across a 63 km2 site, the western part of which is basically a flat zone bordered on the south by the expressway and geographically constrained on the eastern side by the 200 m cliffs of the main site's wady ground morphology.
The aim of the project is to provide a vision for a new city: a dense and compact settlement with a strong focus on mixed land use in order to allow public transport to succeed and generate a livable and people-centered pedestrian environment. A new eco-city characterized by low traffic volumes on one hand, and on the other a contemporary city where the mobility solutions have to relate to a highly demanding society. Residents and visitors are provided with personalized and responsive transport through a sustainable choice among different modes and a blurring of private and public mobility.
This goal is achieved by offering a consistent set of strategies for the road network, car parking and public transport planning, moving away from car-centered mobility towards more sustainable modes of travel.
The proposed solution is not to remove the car from the urban scenario, but instead to include it in a balanced scheme that controls vehicular movement in order to provide a people-friendly environment.
As part of both an active strategy towards the limitation of car usage and a support to the overall multi-modal mobility plan, the city is connected through a network of one-way roads, which host cars and local buses.
The road network is designed to create a rich and vivid environment by keeping the road sections to the absolute minimum. By providing shade from the sun, this approach generates a pedestrian-centered and livable environment.
While in existing cities there is bigger potential in the retrofitting of the road network for more sustainable modes of transport, planning the network from the start allows the compression of the space dedicated to infrastructure as a base line of the project, to public transport's and pedestrians' benefit.
Similarly, not providing a bypass or ring road to the city was a choice driven not only by the ground's morphological characteristics, but also predominantly by the will to prevent induced traffic as a consequence of the presence of a car-convenient infrastructure.
All private vehicle movement within the city will be monitored thanks to a GPS control system that will allow the dynamic understanding of the distribution and density of vehicles throughout the day, constantly informing drivers regarding trip lengths and possible delays on the network.
Variable message panels and the centralized traffic light system—based on real-time information—will redirect vehicle flows when necessary.
The parking strategy is another fundamental planning instrument related to the overall mobility scenario.
The masterplan is conceived as a zero-emission environment. Therefore the only cars allowed to enter the city limits are zero-emission vehicles (ZEVs): electric taxis, residents and visitors' e-vehicles or the car sharing system's fleet.
Those driving a fossil fuel car or even a low-emission vehicle (LEV) park it at the interchange car park located on the level west side of the site and connect to the internal public transport system.
Within the city limits, small parking structures are evenly distributed across the city fabric, one every 150m, providing public parking spaces for the residents. One every two parking structures hosts some public parking for visitors; very limited car parking is planned at destinations such as retail outlets or offices, thereby discouraging the use of private vehicles.
As a result, a150m buffer from the parking facilities is maintained for the residents and a wider 300m buffer for the other functions and users.
The parking infrastructure has basically been unbundled16 from the land use functions, removing the concept of dedicated car park and spreading it across the urban fabric.
Another aspect of the proposed parking system begins from the concept of pricing strategy that in recent years has started to be fully understood in its potential for managing traffic flows, and pushes it further.
A dynamic pricing strategy would force users to internalize the externalities related to car usage, making the car trip still possible but less appealing.
Depending on the chosen trip timeframe and on the distance between origin and destination, the e-park management system will propose a parking fee to the user.
This pricing will be variable and, for instance, will be higher for peak hour or very short trips and proportional to the traffic volumes registered on that specific part of the network. As a consequence the system itself could divert the user's trip destination, offering a more distant car park location to prevent the desired area from becoming too congested.
The parking strategy therefore aims to define a demand-responsive management system that constantly ensures a better match between demand and supply.
The project represents a best-case example of a transit-oriented city where an efficient and therefore attractive public transport system, which has the competitive advantage over the private car, is the main planning guideline.
As an adaptive city17, there is a strong relationship between its urban shape and characteristics, and the public transport system. The city presents a linear form that hosts the spinal light rail transit (LRT) system, where the areas in proximity of the transit stops are characterised by higher densities.
The LRT provides a fast connection through the development, integrated with a series of local bus lines which guarantee the distribution throughout the urban fabric. The line runs on a dedicated path that designates the city's main connector, flanked by pedestrian routes to guarantee pedestrian connectivity. Moreover, motor vehicles are not allowed to circulate on the main spine and the exclusive use of the dedicated lanes by public transport enhances the system's efficiency.
A transit oriented development (TOD) is defined as an area located within a limited buffer from a public transport stop, therefore constituting a transit line linking a series of discrete areas. For the project's public transport network, the buffer radius of the LRT stops has been conceptually expanded to a distance that can be covered by feeder routes bringing users to the main line. The result of this shift is that the stop buffers overlap, creating a continuous area rather than discrete points along a link. In this definition, the transit corridor is no longer linear but effectively becomes a network.
The expansion of the area of analysis yields a synergic system where feeders provide ridership and reinforce the role of the TOD as a hub, thereby placing emphasis on pedestrians and interchange.
The second level local transport system is formed by as a series of mostly one-way bus routes looping between two or three LRT stations, where transport interchange is available. Similarly to what Paul Mees18 analyses of the TTC's19 system, aside from linking with the spinal system, the bus routes link to each other to cater for cross-urban travel and easy transfer becomes the key to achieve the maximum flexibility for public transit trips. The bus route length guarantees a maximum travel time of 10 minutes and a system average headway of 4minutes.
The transfer-based system, along with the integrated network's high frequencies, guarantees the efficient coverage of the whole masterplan area.
Increasing public transport stop buffers leads to the inclusion of another key element to the transit scenario: soft mobility or non-motorized transport (NMT)20. The public transit stop becomes a point of interchange between one mode of transport and the next, where, as described by Paul Mees, "every transit user is also a pedestrian"21. As stated above, this points to the need to consider the microenvironment within the study area to create pedestrian and bicycle-friendly environments. The improvement of the urban context through which soft mobility moves becomes a key part of the conception of a livable transit corridor.
The presence of this urban quality in the project, along with an integrated management system, allows the planning of a mobility on demand system within the overall transport framework, offering a third level of service that further enhances the system's flexibility. In this project, mobility on demand not only provides a solution to the well-known last mile problem22, but also offers a true alternative and self-standing mode of transport that is integrated with the rest of the public transport network.
Mobility Management System
The parking dynamic pricing strategy, the dynamic signaling at the road network's junctions, the public transport and MoD real-time management system, all fall under the key element of the sustainable mobility plan: an integrated mobility management system that can coordinate and optimize both the multi-modal public network and the city's private mobility.
Allowing a constant exchange of information between the provider and the users will create a synergy between network and demand, defining the systems' adaptivity and its demand-responsive characteristic.
The mobility management system will allow the dynamic resolution of issues related to insufficient parking availability as well as possible congested areas, always ensuring efficient movement of private and public transport.
It will also guarantee the management of energy stored in the vehicles' batteries; the consistent storage capacity provided by the vehicle fleet will be used to address peak demand by feeding energy back into the grid (when allowed by the vehicle owner).