The CAREV-S spatial study
1.0 Introduction
The spatial study makes use of spatial justice principles to further develop the idea of platooning, swarming and traffic-based rhythms as a choreographed system with smaller connected autonomous renewable energy vehicles (CAREV-S). Choreographed, flowing traffic is the ‘dream’ of traffic engineers. Platooning, swarming and other logistical concepts are referenced by various connected autonomous vehicles (CAV) studies in energy ‘efficiencies’. I argue that a CAREV-S system is a necessary part of the production of space. This approach shifts the current orthodox debates about private vehicle use in the city.
My explanation is that for many, a private vehicle is an essential transport modality without which citizens would not be able to work or move around. The ‘production of space’[1], is a political role which deepens our understanding of how we use space and relate to the places in which we work and live. For most, life in a city would be considerably more challenging without a vehicle. Creating a CAREV-S vision of a flowing, functioning and ecological transport modality while the population and consumerism increase creates an opportunity to approach the field with optimism. It asks questions such as ‘How do we want to live with CAREV-S in the public realm?’ and ‘Can such a system be reimagined aesthetically?’.
This spatial study undertook a systematic process of ergonomic study including a case study (Surry Hills, Sydney), lane width (spatial) calculation and capacity studies of CAREV, as well as the parametric modelling of standard vehicles and narrower vehicles. This systemic and essentially spatial approach provided data about environmental and active transport space that could be redistributed. It also provided data about vehicle capacity in road space that revealed information about city functionality, resilience and flexibility. The study culminates in an urban heat island (UHI) study, which considers cumulative environmental effects, allowing a further environmental justice investigation to occur, namely,'How can we make CAREV-S cities cooler'?
The study has several parts:
Ergonomic study with lane width (spatial) calculation
Case study location and network
Standard vehicle capacity study of various CAREV in various road formats (a control study)
Smaller vehicle capacity study of various CAREV-S in various road formats
Comparative analysis
UHI in the case study area
Findings
The details of each part of the study with sample drawings are provided below.
1.1 Ergonomic study with lane width (spatial) calculation
This is a selective study of a diversity of human forms seated in a vehicle. The study includes universal access for a diversity of user types, babies, children, teenagers, adults, aged, and disabled person cohorts to ensure the system is just and inclusive of all people. Seating is a study limitation, on the basis that most transportation by road is safely undertaken while seated.
The study limitations are for current ergonomics for standard vehicle seats that accommodate a diversity of users.
Existing vehicle dimensions (four- and six-seater vehicles) and trucks are provided with volumetric and dimensional analysis; the seating arrangements reference Mitchell et al. (2010)[2]. Five typical vehicle dimensions are included.
Future CAREV-S dimensions, that is for a CAV (no human driver) are based on seating arrangements that do not require a human driver for the vehicle for one-[3], two-, four-[4] and six-seat[5] configurations; seating arrangements also reference Harrow (2020)[6]. Three small vehicle dimensions are included in the spatial investigation.
Assessment of vehicle dimensions by dimensional analysis
The following is a summary of [Drawing 1 CAREV_SErgonomic Study]:
The study focused on smaller vehicles, and the modelling confirmed that existing vehicles such as buses, trucks, container and freight moving vehicles, cranes and similar would be able to use the CAREV-S road system.
The study was prepared for spatial analysis for plan arrangements (2D) and in three dimensions (3D).
1.1.1 CAREV-S ergonomic research findings: narrower vehicles, narrower lanes
The reductions in all seats should reflect the use patterns[7] (68% of vehicles in Australia have one occupant, the driver; an additional 5% have two occupants;i.e. a total of 73% of vehicles have two occupants or less). Therefore, vehicles with two or less seats would reflect the use patterns. It could be argued that two-seat CAREV-S should dominate (up to 70% of vehicles); a majority of two-seat and one-seat vehicles would reflect suitable use pattern outcomes. CAREV technology allows for the omission of side mirrors and handbrake space and other vehicle design changes from ergonomic and vehicle technology analysis. Vehicles with two-seater configurations allow for tandem or conference seating arrangements, the difference being an increase in the length of the two-conference-seat format vehicle.
The smaller vehicle format was dimensionally assessed against Mercedes Smart and Renault Twizy, both small vehicles that are currently in the market. In the case of existing two-seat vehicles, they are currently designed with both seats forward side-by-side facing, whereas the CAREV-S allow for tandem or conference-style configurations. As a result of the reduction in vehicle width, narrowing of lane widths is possible. For this ergonomic study, the lane dimensions of 1900mm allow drift space of 250mm on either side of the four-seat vehicle, which Is a total of 500mm between vehicles.
Table of comparative analysis of existing vehicle sizes:
In the two-seater CAREV-S format, it would be possible to allow two vehicles to pass each other in a standard lane. The drift dimensions (space between vehicles travelling at speed) would require further testing once the technology is available. The narrower lane requirements including the drift space will form part of the study in the road typology.The lane width for this study is an internationally accepted standard of 3500mm.
1.2 Case study– location and network
A local case study from which other research can emerge was required, and I decided that Surry Hills, a suburb of Sydney, which has a typical inner city road network, would be suited to the research. The study area is familiar and accessible, and as a typical gridded 19th-century suburb it has qualities that could be expanded to wider studies. The study area included five road types that make up the suburb: 1. motorways, 2. arterial roads, 3. feeder routes (no parking), 4. local arterial and 5. local roads in a 370-ha area. This is typical of a large number of Australian city formats. The road network configurations form the structure for parametric modelling that allows for metrics to be continuously updated with graphic output as a spatial capacity study. Therefore, each road type capacity could be assessed.
This aerial map shows the location of Surry Hills in relation to Sydney CBD. Studio Colin Polwarth is located in Surry Hills, making the study area accessible and known to the practice.
This aerial map shows the location of the study area in Surry Hills. The five major road types are identified in this diagram. The study area is 370 ha. The same area will be used in the UHI study.
1.2.1 Use pattern diagram
The spatial investigation includes a diagram of the road network to calculate capacities. Current road types accommodate current typical Australian passenger vehicle use patterns[8]:
· 63% of passenger vehicles have one person (a driver)
· 7% of passenger vehicles have two people (one is a driver)
· 30% of the remainder of typical traffic is a variety of other vehicles including trucks, buses, vans and emergency services, and are larger format vehicles
A controlled CAV study using current vehicle configurations (i.e. four-seater generally) was developed[9] as a control study.
This photograph of a typical Sydney motorway in peak hour traffic confirms the census data that the majority of vehicles on the road have one or two occupants only. The yellow line shows the ‘drift space’ required by human drivers to navigate 3500mm lane widths. The spatial aspects of lane width and occupancy are used in this study to challenge existing assumptions about how CAREV and CAREV-S should be developed.
1.3 Standard vehicle capacity study of various CAREV in various road formats (control study)
The existing road typology study provides baseline metrics for the five road types. The five road types are typical of those seen in the road network in Surry Hills but form part of a wider road network system. Baseline metrics are used to compare case study metrics.
The diagrams are summaries of parametric modelling of existing motorway and arterial road capacities. These drawings are control drawings to test the model against current known statistics for road capacities. They make assumptions about the ‘safe distance’ between vehicles at designed speeds. The results are tabulated below:
Table of existing road typology calculations used in this study: speed, area, percentages of spaces[10]
1.3.1. Investigation into CAV using existing vehicle dimensions
This study investigates the magnitude of effects of existing standard vehicle sizes with CAV technologies, (lane assist, no rear-view mirrors and utilizing existing standard 3,5m traffic lanes) that could be achieved if maximised. This study's findings for increased capacity of roads through CAV are supported by other similar studies such as Alonso Raposo et al. (2018) and Hua Sha (2020). This study was prepared to assist in understanding the effects of CAV technology (no mirrors, reduced handbrake space, lane assist and drift space, and platooning [no swarming]) using standard current vehicle dimensions (for instance, 5500lx2200wx1400h) in a standard lane configuration of 3500mm. The results are an increase in the capacity of road over human-driven vehicles throughput as follows:
Summary: CAV technologies in this study may increase vehicle throughput capacity by about 200 to 300% in motorways, about 150 to 300%, arterials, and approximately 200% on feeder routes, 200% on local arterials and 130% on local roads using existing vehicle sizes based on the assumptions listed in the study.
1.4 CAREV-S road typology and capacity study
This study is based on maintaining the existing five road typologies and adjusting two fields:
1. The vehicle sizes are reduced as follows: 63% of vehicles are one- or two-seater (CAREV-S), 7% are two-seater (CAREV-S) and the remainder (30%) are four-seater and larger vehicles. These figures parallel average use patterns in Australia
2. The lane width is reduced to 3200 mm for the larger vehicles, and two of 1900 mm, as CAV technology does not require the same lane space as a human-driven vehicle
The study investigates how many additional lanes can be added with CAREV-S (CAV technology and smaller vehicle types). The study investigates three options that arise from the use of smaller vehicles:
1. Maximizing parking
2. Maximizing active transport pathways
3. Maximizing environmental (landscape space)
The above diagrams are samples of the parametric modelling of CAREV-S vehicles and larger CAREV vehicles mixed on a motorway and arterial road as capacity studies. The increase in vehicles in the drawings demonstrates CAREV-S's ability to platoon and swarm in combination with smaller vehicle formats (70% of vehicles are two-seater CAREV-S format). The results are tabulated below:
Table of CAREV-S typology calculations used in this study: speed, area and percentages of spaces; the study demonstrates maximum output:
1.5 Comparative analysis
The following diagram provides a visual comparative analysis of the existing and the CAREV-S format of the reconfigured road space. The diagram shows the increased capacity of CAREV-S due to the reduced size of the vehicles and the ability of the technology to platoon and swarm in selected lanes. The comparison is visualized against the existing road conditions. The table below summarizes the capacity increases spatially, noting the assumptions that were made in preparing the study[11].
Tables of comparative analysis for parking, environmental area and active transport options
1.6 The CAREV-S spatial study findings summarized
Overall the capacity of roads has significant increases for smaller vehicles with CAREV technology as follows:
CAREV-S technology in this study increases the road capacity throughput
The maximized capacity of motorways could increase, by about 600% to 1000%, depending on the arrangement of CAREV platooning, braking distances and vehicle types
The capacity of arterials could increase for CAREV by about 300% to 680% depending on the arrangement of small vehicle platooning, braking distances and vehicle types
The capacity of feeder routes could increase for CAREV by about 250% to 541%, accepting all lanes are designed for smaller vehicles' braking distances and vehicle types
The capacity of local arterials and roads could increase for CAREV by about 600% to 800% accepting all lanes are designed for smaller vehicles' braking distances and vehicle types. CAREV parking in arterial and local roads introduces frequent traffic conflicts for entering and exiting car parking zones, thereby reducing the possible increase in lane capacity; this has not been modelled in this study
The study indicates that the following spatial options in addition to the vehicle capacity increase:
Parking could be increased by about 300% on local and arterial roads if parking is identified as a priority
The area of active transport (shared path) could be increased by 33% in local arterials and 40% in local roads; this would be a total of 40% of the road corridor area dedicated to active transport in local arterials and 49% in local roads while parking is maintained in local roads at the same levels as existing vehicles (372)
Alternatively, environmental areas could be increased by 9.8% in local arterials and 9.7% in local roads if active transport and parking were maintained on local roads at the same levels as existing vehicles (372). These increased environmental areas will be used in the UHI study
Increased environmental areas could include trees and landscaping areas, both of which would have environmental benefits including UHI reduction effects
1.7 Urban heat island (UHI) study in the case study area
The UHI is used to develop a basic simulation model to understand if this additional 9% landscape area derived from the CAREV-S spatial study could reduce the UHI effects or if this metric could be too low to offer any heat island reprieve. Appreciating the magnitude of reductions of UHI effects through CAREV-S required further research. A basic universal thermal climate index(UTCI) model could provide initial results that could then be used to develop further research, or even question the conclusions of this study.
The study area was set as the same area in which the CAREV-S capacity study was undertaken. The study area of the model and suburb is 370 000m2.
The study area was at the limits of computer operations; beyond this modelling, a supercomputer would be required to compile the model. A series of models were co-joined. Initial test models were developed during the initial development stage and were adjusted to ensure that some results would be possible within the study time and resources[12]. The climatic data was supplied by the Australian Bureau of Meteorology for Surry Hills, Sydney in 2020. The simulation took place in September and October 2021[13].
1.7.1 UHI findings
Notwithstanding the modelling limitations[14], it is evident that overall CAREV-S could be anticipated to provide multiple environmental benefits by increasing landscape space, reductions in engine temperatures (electric vehicles) and increases in shade trees (the model included mature trees); overall this would result in reductions in UHI effects through mass and distributive tree planting across the study area within the public realm.
The summary results are that for a CAREV-S city with 9.8% extra landscape area and about 10% area for shade trees more or less equally distributed across the model in addition to the existing trees, temperate reductions of three to four degrees centigrade at all times of the year in 2021 were found for this UHI study in Surry Hills NSW. The results are represented graphically in 24 models in summer, winter, spring and autumn.
A sample of a detailed diagram of the UHI as a visual demonstration. The black dots represent the additional 585 trees planted as a result of CAREV-S typologythat allows for an additional 9% of road area for environmental planting (trees).
Comparative visual analysis of UHI as a visual demonstration, this sample is for September 2021. Existing conditions are shown at 3 pm, 1 pm and 8 pm on the left. The simulation with an additional 585 trees planted for the CAREV-S vehicle typology with an increased 9% area for mature tree planting in streets at 3 pm, 1 pm and 8 pm on the right-hand side. The colour change demonstrates a three to four-degree reduction in UHI temperatures.
1.8 Study summary findings
The central argument presented in the spatial study is related to the change in the fleet and its design, as it is related to the city and an environmentally systemic approach. I argue thatthis is necessary fora response to climate change and improved public health outcomes. The combined study identifies a shift in the design strategy and attitude regarding the relationship of the vehicle to the city and the environmental approach this research takes. The research attempts to articulate the parameter and qualitative changes that shape the city environmentally. The systemic approach also requires a transdisciplinary approach to facilitate industry and academic research and is part of the originality in the debate on shaping the future city.
The shift in paradigm thinking about CAREV-S along with challenging the industry’s levels of autonomy are the core thinking of the purpose of this research. The research develops an ecological framework for CAREV as practice research on CAVs, semiotics and intelligent cities. The emerging insights from the spatial study support the overall PhD framework for a CAREV-S system that is environmentally and semiotically systemic in nature. The spatial study, in combination with semiotic experiments, social and cultural history and technical research, provides a novel approach to the field and the project. This includes architectural drawings, animations and films that make up the research investigation as practice. The thesis challenges existing paradigms by providing new insights through an evolution of thought. Please refer to the conclusion section.
1. HenriLefebvre, The Production of Space, trans. by Donald Nicholson-Smith, 1st edition (USA: Malden: Wiley-Blackwell, 1991).
[2]. William J. Mitchell, Chris E. Borroni-Bird, and Lawrence D. Burns, Reinventing the Automobile: Personal Urban Mobility for the 21st Century (Cambridge, MA, USA: MIT Press, 2010).
3. Data results from Victorian Government surveys show that on average 75% of Melbournians use private vehicles to go to work and that they are occupied on workdays by on average 1,2 people; the deduction is that the vehicle is a mode of production in that it facilitates economic activity. Peter Cebon and Danny Samson, ‘Using Real Time Information for Transport Effectiveness in Cities’, City, Culture and Society, 2.4 (2011), pp. 201–10 <https://doi.org/10.1016/j.ccs.2011.12.001> and Department of Economic Development, Jobs, and Government of Victoria, ‘Data and Publications’, 2007, Victoria <https://transport.vic.gov.au:443/about/data-and-research/vista/vista-data-and-publications> [accessed 13 August 2021].
[4]. A three-seat configuration was not included in the study; however, future studies should investigate the percentageof use and desirability of such a configuration.
[5]. Seating arrangements in excess of six people fall into the category of a microbus, which is arguably a different vehicle classification.
[6]. Dale Harrow et al., ‘Driverless Futures: Design for Acceptance and Adoption in Urban Environments’ (Royal College of Art, London., 2020), 978-1-910642-32-0 <https://researchonline.rca.ac.uk/4627/> [accessed 21 January 2021].
[7] These statistics are from 2022 census data, and are consistent with data from 2013 for about 70-75% of vehicles have one occupant in Australia.
7.Bureau of Statistics, Commonwealth of Australia, ‘More than Two in Three Drive to Work, Census Reveals’, Australian Bureau of Statistics (c=AU; o=Commonwealth of Australia; out =Australian Bureau of Statistics, 2017) <https://www.abs.gov.au/ausstats/abs@.nsf/mediareleasesbyreleasedate/7DD5DC715B608612CA2581BF001F8404> [accessed 2 December 2022].
[9]. Appendix O - Part B1 investigation into CAV using existing vehicle dimensions.
[10]. Notable metrics in this study are the following:
Arterial roads and feeder routes in this study have higher capacities than motorways. This is not representative of reality as arterial roads have traffic lights that slow throughput. Active transport areas are in the 7% range for motorways, but 18–30% for all other roads. Motorways have 66% of the area available for landscape (environmental) mainly due to a larger footprint, road geometry and large infrastructure required, e.g. major cross drainage and civil works, whereasarterial roads have 20% of the area for environmental landscape. For all other roads, the metrics allow no space for landscape.The study is based on typical contemporary fossil-fuelled vehicles of 2400mm in width and 5200mm long. Braking distance is the distance required by driving regulations and an assumed human reaction time to incidents, acceleration and deceleration between vehicles at normal operating speeds. Capacities are theoretical, based on streamlined flows of traffic, that is, the study does not represent all factors such as slowing due to driver reaction times..The key differences in infrastructure required for various road typologies contribute to significant differences in corridor footprints, e.g. major cross drainage, waterway crossings, road geometry and major/minor traffic intersections. Traffic congestion is excluded in modelling as it has dynamic implications that affect capacity and alternate route option selection (i.e. human intervention). Lane changes, overtaking, reactions and on-route decision-making at interchanges and interactions can impact theoretical capacities; therefore, these are not represented in the study. Traffic network simulation modelling technology is expected to be integrated with synthetic intelligence that will help increase traffic management and regulation to maintain optimum flow and capacities. The lane capacity per km section on the model does not include network performance considerations.
[11]. The CAREV-S + Road Typologies Studies provides opportunities for the following:
· An Increase In road capacity, and this will result in existing roads not having to be widened to accommodate the technology; it is effectively an adaptive re-use of the existing road space
· The principle extends the life of existing road networks
· CAREV technology allows for narrower lanes, as the technology has more accurate navigation than human-driven allocations
· The study accepts that for motorways and feeder routes, larger vehicle types (in the range of 2400mm width), which is consistent with container and freight width requirements, would be required. The CAREV technology allows for narrower lanes, as the technology has more accurate navigation than human-driven allocations
· The remainder of the existing lane configuration would be reconfigured with line markings to suit the smaller vehicles (CAREV-S); this is a simplified assumption that no engineeringto pavement infrastructure and other features is required for CAREV-S.
· Smaller vehicles will increase the capacity of the roads; refer to the table below
· CAREV-S technology allows for platooning and swarming that results In significant capacity improvements
· CAREV-S vehicles have a lower pollution ratethanfossil-fuelled vehicles, less noise, less noxious gases and less carbon dioxide; therefore, these are additional environmental benefits
· Where required roads currently suffering a lack of parking space could benefit froman increased parking capacity with smaller vehicles
· Where roads currently suffering congestion could be relieved with CAREV-S technology and vehicle sizes using swarming and platooning
· Where roads are required to maintain parking levels, the smaller vehicles allow for a 20–30% increase in the landscape area. These areas could contribute to reducing UTI effects
· Where roads require additional active transport routes (dedicated), one side of the road could be changed to an active transport route.This strategy has been used in Sydney, in Bourke Street in the study area; however, in the Sydney study, there was a reduction in vehicle parking as the vehicle sizes did not change
[12]. Materiality changes
Initial modelling included materiality changes to 9% of the model area; however, the model results were inconclusive and regarded as unlikely to provide suitable data due to the limitations of the hardware. Therefore, we took the approach to include a 9% additional shade cover spread across the model on the basis that an increase of 9% in the environmental area could result in shade effects that could result in lower heat island effects.
[13]. The UTCI model parametric included:
· The clothing levelconsidered is 0.4 clo (t-shirt) for summers and 1.0 clo (jacket) for winters
· The activity level considered is 3 MET (low activity movement for a gathering space)
· The 'no thermal stress' comfortable category usually is limited to 26°C internationally. As this is not achievable in hot climates, based on the Australian model of adaptive comfort, the outdoor thermal comfort can be stretched to 32°C.
· Source: https://www.sciencedirect.com/science/article/pii/S0360132315302171
· We established control models, that is existing heat island studies of existing conditions, and then added the CAREV-S benefit of 9% area and additional shading and re-ran the model to test the results conducted at the following dates/times:
· Summer solstice, 22 December
· Autumn equinox 21 March
· Winter solstice 21 June
· Spring equinox 23 September
· Further limitations on the study included the date and time restrictions for the model which included 8 am, 1 pm and 3 pm for each of the following (12x2 models). The data provided incorporated factors affecting outdoor thermal comfort.
[14]. Several preoccupations complicated this research, not only are the CAREV-S technologies currently unavailable but a complete fleet change to smaller CAREV-S is a hypothetical condition. The model also assumes the use of fully mature trees being supplied, whichaffects the reductions in temperatures, whereas trees require at least 10 to 15 years to reach maturity and full shade effects.
Furthermore, the study assumes fully evergreen trees, whereas, in Surry Hills, Sydney, the street tree palette includes many deciduous trees, the use of which would impact the results, especially in winter. Furthermore, additional model simulation inputs for materiality and reductions in temperatures through the general plants (shrubs, etc.) could also affect the results leading to lower temperature effects.