2023 Volume 11 Issue 4 Pages 19-38
Colombo is a spontaneously developed city with high rates of traffic accidents. Although laws and regulations emphasize safety measures, the number of traffic injuries remains high, while fatality rate increases. Therefore, designing streets to spontaneously prevent users from accidents despite recklessness is vital, and street design phase becomes important in urban development. So far, urban planning in Sri Lanka has been merely based on expert knowledge, and user perspective remains unknown. Stakeholder discussions confirm the need for one comprehensive street design standard other than the existing laws on selective aspects and structural specifications. Foremost it is essential to understand the expert and user perspectives on the prominence of various components of streets in determining user safety and comfort, and thus becomes the aim of this research. Urban street components that determine physical safety and comfort are summarized through a literature review, and case study. The quantitative research method involves obtaining a comparative score on the priority of identified components in determining physical safety and comfort by the public and experts through online surveys, and conducting descriptive statistical analysis based on means of the scores to identify the hierarchy of priority by the two groups. Accordingly, components are categorized as mandatory to ensure physical safety and comfort, enhance physical safety and comfort when present, and affect physical safety and comfort when present. This outcome contributes to the sustainable future development of Sri Lankan urban streets by incorporating in design policy development and methodology and sets an example to incorporate expert and public opinions in other contexts.
Urbanization is an inevitable challenge in contemporary development, with a growing population (The World Bank, 2020b) and technology. It is a global phenomenon that is accelerating rapidly especially in developing nations (Al-Rashid, Nadeem et al., 2021).Streets and squares are major forms of urban space (Krier and Rowe, 1979), with streets being the primary links of urban spaces. Therefore, they are accessed by a larger population on a daily routine. Asian streets were known to be pedestrian-friendly in the past (Kaur, Singh et al., 2021). However, with rapidly increasing vehicle ownership (The World Bank, 2020a), and car-oriented road development, urban streets are becoming unsafe for users (Nakamura, 2021) as could be determined from the rate of accidents and traffic fatalities recorded by the United Nations Global Status Report (World Health Organization., 2018). Such vehicle-oriented roads are a threat to both pedestrians and motorists, harming the vitality of the city by causing traffic hazards (Nakamura, 2021). These rates remain high despite traffic laws and regulations being developed, implemented, and improved through the years to ensure user safety and comfort of streets. Annually approximately 1.3 billion die and 20-50 million people get injured due to road traffic crashes (World Health Organization, 2021). Hence, recent years have seen a rise in the importance of traffic safety as a global urban management concern (Chen, Yuan et al., 2023). Speeding, unsafe road infrastructure, and inadequate enforcement of traffic laws are a few of the main causes of global traffic crashes (World Health Organization, 2021).
Unsafe road infrastructure being one of the main causes of traffic crashes (World Health Organization, 2021), is important to further improve the urban design approach. A comprehensive evaluation of streets is important to facilitate the various needs of different user categories (Nakamura, 2021) when planning, or even improving an established city. Colombo is an established city that has rapidly expanded by 288% footprint from 1992 to 2014 (Subasinghe, Wang et al., 2022). Sri Lanka street designs are not pragmatic as they are primarily based on expert knowledge and international standards, and not an inclusive plan involving user opinion as revealed through discussions with the planning authorities such as the Road Development Authority (RDA), Urban Development Authority (UDA), and Colombo Municipal Council (CMC). A collaboration between design professionals and stakeholders is required to formulate an inclusive street design with improved quality (the Department for Transport under licence from the Controller of Her Majesty’s Stationery Office, 2007). Aggregate indicator identification aids planners in developing a healthy and sustainable environment (Bartzokas-Tsiompras, Photis et al., 2021). Although any national development policies and planning strategies could be based on sustainability concepts, there is significant data scarcity in identifying walkability indicators of streets for a micro-level assessment (Bartzokas-Tsiompras, Photis et al., 2021). Community participation in planning decision-making is necessary to achieve sustainable development (Zanudin, Ngah et al., 2019). Identified indicators should be assessed based on both expert and user perspectives to understand the hierarchy of the importance of each component of the street when designing a safe and comfortable environment. This approach leads to the formulation of a pragmatic development plan. However, the literature review and stakeholder discussions reveal the research gap in such an inclusive study, and the question of which component needs to be prioritized in street development remains unanswered. The research questions on what are the components that ensure user physical safety and comfort at urban public streets, whether there is a difference of opinion among the experts and public in the prominence of components, and what is the prominence of identified components are answered through this study. The answer to the research question on which components should be prioritized to ensure user physical safety and comfort at urban streets helps develop countries where street infrastructure improvements are planned at different phases as per a limited budget. Thus, this research aims to understand the expert and user perspectives on the prominence of various components of streets in determining user safety and comfort.
The objectives of the study are to identify the components of urban public streets, analyse expert and public perspectives to identify the prominence of urban street components in determining physical safety and comfort of users and conclude which components are mandatory, enhance the safety and comfort, and affect the safety and comfort merely when present.
A literature review is primarily conducted to identify the components and their indicators that are essential in determining the physical safety and comfort of users in urban streets. 10 components of streets that influence user physical safety and comfort were concluded (Table 1) and validated through case study analysis.
| Identified components and indicators of urban streets | Referred Assessment models/ Audit tools | |
|---|---|---|
|
Sidewalk Presence of element Dimension/ergonomics Accessibility |
National Association of City Transportation Officials (National Association of City Transportation Officials, 2016). Walking Suitability Assessment Form (WSAF) (Emery, Crump et al., 2003). PIN3 Neighbourhood Audit Instrument (Evenson, Sotres-Alvarez et al., 2009). Irvine Minnesota Inventory (I-M) (Boarnet, Day et al., 2006). Analytic Audit Tool (Brownson, Brennan Ramirez et al., 2003). Livable Communities: An Evaluation Guide (Kihl, Brennan et al., 2005). Systematic Pedestrian and Cycling Environmental Scan (SPACES) (Pikora, Bull et al., 2002). Microscale Audit of Pedestrian Streetscapes (MAPS) (Brownson, Brennan Ramirez et al., 2003). Critical factors influencing the comfort evaluation for recreational walking in urban street environments (Ma, Chau et al., 2021). Assessing a walkable environment in Jalan Tuanku Abdul Rahman, Kuala Lumpur, Malaysia (Sarimin and Ibrahim, 2018). |
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Carriageway Presence of component Dimension/ergonomics Accessibility |
National Association of City Transportation Officials (National Association of City Transportation Officials, 2016). Path Environment Audit Tool (PEAT) (Troped, Cromley et al., 2006). Quality Assessment System for Completed Road Works (Construction Industry Development Board Malaysia, 2011). Irvine Minnesota Inventory (I-M) (Boarnet, Day et al., 2006). Systematic Pedestrian and Cycling Environmental Scan (SPACES) (Pikora, Bull et al., 2002). Microscale Audit of Pedestrian Streetscapes (MAPS) (Brownson, Brennan Ramirez et al., 2003). |
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|
Protective barriers and boundary makers Presence of component Dimension/ergonomics Appropriate location |
Path Environment Audit Tool (PEAT) (Troped, Cromley et al., 2006). Quality Assessment System for Completed Road Works (Construction Industry Development Board Malaysia, 2011). Livable Communities: An Evaluation Guide (Kihl, Brennan et al., 2005). A new assessment model to evaluate the microscale sidewalk design factors at the neighbourhood level (Aghaabbasi, Moeinaddini et al., 2017). |
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|
Public amenities Dimension/ergonomics Appropriate location |
Path Environment Audit Tool (PEAT) (Troped, Cromley et al., 2006). Walking Suitability Assessment Form (WSAF) (Emery, Crump et al., 2003). PIN3 Neighbourhood Audit Instrument (Evenson, Sotres-Alvarez et al., 2009). Irvine Minnesota Inventory (I-M) (Boarnet, Day et al., 2006). Analytic Audit Tool (Brownson, Brennan Ramirez et al., 2003). Neighbourhood Environment Walkability Survey (NEWS) (Saelens, Sallis et al., 2003). Livable Communities: An Evaluation Guide (Kihl, Brennan et al., 2005). Microscale Audit of Pedestrian Streetscapes (MAPS) (Brownson, Brennan Ramirez et al., 2003). Critical factors influencing the comfort evaluation for recreational walking in urban street environments (Ma, Chau et al., 2021). Assessing a walkable environment in Jalan Tuanku Abdul Rahman, Kuala Lumpur, Malaysia (Sarimin and Ibrahim, 2018). A new assessment model to evaluate the microscale sidewalk design factors at the neighbourhood level (Aghaabbasi, Moeinaddini et al., 2017). "Development of planning and design standards for sidewalks: The role of municipal to provide safe and comfortable environment for users of sidewalks in the city of Baghdad(Aown, 2018)." |
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|
Integrated public utilities Dimension/ergonomics Appropriate location |
National Association of City Transportation Officials (National Association of City Transportation Officials, 2016). Path Environment Audit Tool (PEAT) (Troped, Cromley et al., 2006). Quality Assessment System for Completed Road Works (Construction Industry Development Board Malaysia, 2011). "Development of planning and design standards for sidewalks: The role of municipal to provide safe and comfortable environment for users of sidewalks in the city of Baghdad(Aown, 2018)." |
|
|
Shading facilities Dimension/ergonomics Appropriate location |
National Association of City Transportation Officials (National Association of City Transportation Officials, 2016). PIN3 Neighbourhood Audit Instrument (Evenson, Sotres-Alvarez et al., 2009). Irvine Minnesota Inventory (I-M) (Boarnet, Day et al., 2006). Analytic Audit Tool (Brownson, Brennan Ramirez et al., 2003). Neighbourhood Environment Walkability Survey (NEWS) (Saelens, Sallis et al., 2003). Microscale Audit of Pedestrian Streetscapes (MAPS) (Brownson, Brennan Ramirez et al., 2003). Assessing a walkable environment in Jalan Tuanku Abdul Rahman, Kuala Lumpur, Malaysia (Sarimin and Ibrahim, 2018). A new assessment model to evaluate the microscale sidewalk design factors at the neighbourhood level (Aghaabbasi, Moeinaddini et al., 2017). "Development of planning and design standards for sidewalks: The role of municipal to provide safe and comfortable environment for users of sidewalks in the city of Baghdad (Aown, 2018)." |
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|
Landmark and special features Dimension/ergonomics Appropriate location |
Critical factors influencing the comfort evaluation for recreational walking in urban street environments (Ma, Chau et al., 2021). A new assessment model to evaluate the microscale sidewalk design factors at the neighbourhood level (Aghaabbasi, Moeinaddini et al., 2017). "Development of planning and design standards for sidewalks: The role of municipal to provide safe and comfortable environment for users of sidewalks in the city of Baghdad (Aown, 2018)." |
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|
Overpasses and underpasses Accessibility Dimension/ergonomics Appropriate location |
A new assessment model to evaluate the microscale sidewalk design factors at the neighbourhood level (Aghaabbasi, Moeinaddini et al., 2017). | |
|
Atmospheric factors Tolerance level |
Path Environment Audit Tool (PEAT) (Troped, Cromley et al., 2006). Assessing a walkable environment in Jalan Tuanku Abdul Rahman, Kuala Lumpur, Malaysia (Sarimin and Ibrahim, 2018). |
|
|
Form and morphology Legibility Scale Morphology |
Systematic Pedestrian and Cycling Environmental Scan (SPACES) (Pikora, Bull et al., 2002). Assessing a walkable environment in Jalan Tuanku Abdul Rahman, Kuala Lumpur, Malaysia (Nakamura, 2021). "Development of planning and design standards for sidewalks: The role of municipal to provide safe and comfortable environment for users of sidewalks in the city of Baghdad (Aown, 2018)." |
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Based on the above-listed (Table 1) assessment models, and case study observations the components that affect the physical safety and comfort of users were identified. As per the literature study, the above 10 components are assessed under different proposed models separately for walkability, sidewalk standards, environmental audit, sidewalk design factors, and quality at construction etc. No model is comprehensively designed including every component that determines the overall safety and comfort of the users at urban public streets, and neither emphasises the priority of components. Thus, the literature review clarifies the gap on a comprehensive study of identifying all components that ensure user physical safety and comfort at urban public streets, and their prominence as per an inclusive statistical analysis.
The research was based on the online survey on scoring of identified components that determine physical safety and comfort of urban public streets to identify a compromised hierarchy to prioritize when designing streets. The components of urban public streets were identified through a literature review (Table 1) and observations of randomly sampled public streets of Colombo.
A case study was conducted through observation technique, based on a random sampling of 12 streets within the municipal council administrative boundary of Colombo, which is a well-identified urban space in Sri Lanka. It was ensured that the 12 samples of streets addressed different categories of urban streets based on usage and capacity. The prime purpose of this case study is to ensure that no elements that affect the physical safety and comfort of users in the urban streets are neglected in the list summarized through the literature review. Elements identified through the literature review that affect the user's physical safety and comfort are confirmed through on-site observations of user behaviour during peak, and non-peak hours during day and night usage of streets. The discomfort or safety threats encountered by users are observed, causes are identified, and thereby relevant priority of components are confirmed. Accordingly, the summarized components were: carriageway, sidewalk, protective barriers and boundary markers, public amenities, integrated public utilities, shading facilities (Figure 1), landmark and special features, overpasses and underpasses, form and morphology, and atmospheric factors.
Carriageway:
A carriageway is a vehicular way that is identified as a component of an urban street. This component includes the elements: traffic lanes, parking, median, illumination, pedestrian crossing, traffic lights and road signages The carriageway facilitates access of motor vehicles.
Sidewalk:
Street pedestrian path along with buffer zones, plantation, illumination, frontage zone, and furniture zone are included in this component. This component facilitates the access for pedestrians as well as other occupiers of streets such as vendors, and street frontage shop owners (National Association of City Transportation Officials, 2013).
Protective barriers and boundary markers:
This component refers to the physical elements that define the boundaries of space and act as a barrier against unauthorized movements or prevent severe accidental collisions. Such elements could be bollards, railings, fences, or any other protective structures.
Public amenities:
Public amenities are user facilities and features that are provided to ensure the comfort of users, such as waste receptacles, transit shelters etc. Such facilities are vital in ensuring the comfort of street usage.
Integrated public utilities:
Integrated public utilities are fire hydrants, outdoor transformers and other service provider installations, and overhead lines placed on the streets. These do not specifically cater the street users, but the presence of such public utilities in streets could influence the safety and comfort of street users.
Shading facilities:
In this study, shading facilities are defined as man-built structures that provide shelter for users within the furniture or frontage zones other than the transit shelters that are considered under public amenities. Shading facilities become an important element in a tropical country like Sri Lanka to protect users from sun and rain.
Landmark and special features:
Landmarks are points of reference to a place (Lynch, 1964). Statues, water bodies such as ponds and fountains, and memorials are considered as landmarks and special features in this study. Landmarks and special features help to locate a place.
Overpasses and underpasses:
Overpasses and underpasses are used to separate vehicular and pedestrian access to avoid safety threats at grade-level crossing (Bandara and Hewawasam, 2020). Vehicular flyovers and pedestrian crossing bridges and tunnels are considered under this component.
Form and morphology:
Lilley (2009) defines urban morphology as the ‘study of urban form’. Urban form is a city’s physical characteristics referring to the size, shape, and configuration of its elements including street type and layout (Živković, 2020). Therefore, in this study, the overall composition of a street determining the legibility and thereby safety and comfort are described as form and morphology.
Atmospheric factors:
Temperature, sound, and odour levels affecting the physical safety and comfort of users are considered as atmospheric factors of streets. The rapidly growing automobile, construction works, and industrial activities in urban contexts have altered the ambient atmospheric composition (Kumar and Maharana, 2020). Therefore, it is important to maintain a tolerable level of temperature, sound, and odour levels to ensure physical safety and comfort of users.
The scoring on the priority of concluded components in determining physical safety and comfort of users was obtained using an online platform. Expert scores were obtained from 35 professionals varying from architects, engineers, town planners, landscape architects, project managers etc. As per the Central Limit Theorem, a sample size of 35 is considered sufficient for expert opinion to obtain a normal distribution curve. The scores were obtained using Excel sheet tables emailed to the selected experts. A score of 100 was to be divided among the identified 10 components of streets that determine physical safety and comfort. This method of scoring is chosen to obtain a comparative score to identify the hierarchy of components to understand the prioritization in planning. The test for extreme outliers was done using Excel sheet applications for the scores obtained, and the data consisted of no outliers. Therefore, a mean value of all the scores obtained was considered as the final expert score for each component.
50 public responses were obtained from users of the streets of Colombo, which included pedestrians, motorists, and bicyclists. A seven-point Likert scale scoring of the components was obtained using an online survey sheet distributed through known contacts to reach the target sample. Extreme outliers test was conducted using Excel sheet applications and there were no outliers identified. Therefore, a percentage of each score out of the sum of scores for all components was obtained for comparative analysis. An ANOVA test was carried out to confirm that there is no difference of opinion among the public user categories, to obtain a single mean value of public scores for the t-test with expert scores. Level of significance of 95% is considered. Therefore, P- value from the ANOVA test being greater than 0.05 for all the street components proved that there is no difference of opinion among different user categories: pedestrians, motorists, and bicyclists.
Potential places of risk in streets of Colombo were identified through a case study of selected streets of Colombo representing different categories.
Public streets in Colombo are present in residential, commercial, and mixed usage zones as per Colombo Functional Zoning by the Urban Development Authority (UDA) Zoning Plan (2020). Accordingly, three case study streets (Figure 2) addressing each usage zone were chosen within the Colombo city boundaries (Urban Development Authority, 2020) to critically and descriptively analyse the state of physical safety and comfort based on on-site observations and measurements, and thereby identify the necessity and contribution of components in determining physical safety and comfort.
For the case study, a 1.2km distance of Galle Road within Colombo-03 was chosen to represent the commercial zone, Cambridge Terrace in Colombo-07 was chosen to represent a residential street, and W A Silva Mawatha in Colombo-06 was chosen to represent a mixed-use zone. Galle Road was chosen considering its significance as a main road serving as a major traffic route in the commercial zone of Colombo. Cambridge Terrace was chosen as it is one of the streets within the residential zone of Colombo. W A Silva Mawatha is a road in the mixed usage zone, with alternative residential and commercial buildings, connecting two major roads: Havelock Road, and Galle Road. The pedestrian underpass at Havelock Road in Colombo-06 was assessed separately to understand the user priority. The analysis is based on on-site observation and measurements to check the availability of components, their physical condition and conformity to contextually applicable standards, and their effect on the safe and comfortable accessibility of users. This method of analysis helps to understand the importance of the presence of a component, and the effect of a component when it is present, leading to clarifying the priority of different components in ensuring user physical safety and comfort.
A descriptive analysis of the case study was carried out through Google Street View and on-site, to understand the realistic issues and compare with the variance of scores between experts and the public. This process contributed to determining the validity of scores from both groups. The comparative investigation of all the above research results was used to understand the prominent components that must be prioritized in designing urban streets to ensure physical safety and comfort, in order to develop a pragmatic plan.
All analyses were done using SPSS software and Excel sheet applications. The scores were obtained from experts and the public to determine the prominence of identified components in determining user safety and comfort in urban public streets.
Analysis of experts’ score:| Component | Mean | N | Std. Deviation |
|---|---|---|---|
| Carriageway | 13.91 | 35 | 5.002 |
| Sidewalk | 15.43 | 35 | 4.680 |
| Protective Barriers | 11.60 | 35 | 4.571 |
| Public amenities | 8.89 | 35 | 2.576 |
| Integrated public Utilities | 8.60 | 35 | 3.155 |
| Landmarks and special features | 6.43 | 35 | 3.432 |
| Overpass and Underpass | 10.71 | 35 | 3.553 |
| Shading structures | 10.26 | 35 | 4.280 |
| Atmospheric factors | 6.66 | 35 | 3.464 |
| Form and morphology | 7.51 | 35 | 2.525 |
| Component | Mean | N | Std. Deviation |
|---|---|---|---|
| Carriageway | 12.67 | 50 | 2.238 |
| Sidewalk | 12.50 | 50 | 2.329 |
| Protective Barriers | 11.25 | 50 | 1.599 |
| Public amenities | 9.33 | 50 | 1.690 |
| Integrated public Utilities | 8.85 | 50 | 2.378 |
| Landmarks and special features | 7.63 | 50 | 2.648 |
| Overpass and Underpass | 10.68 | 50 | 2.471 |
| Shading structures | 9.60 | 50 | 2.334 |
| Atmospheric factors | 9.23 | 50 | 2.586 |
| Form and morphology | 8.26 | 50 | 2.955 |
| Component | Sum of squares | Degrees of Freedom | Mean square | F Statistic/value | P- value | |
|---|---|---|---|---|---|---|
| Carriageway | Between groups | 0.587 | 2 | 0.294 | 0.301 | 0.742 |
| Within groups | 45.913 | 47 | 0.977 | |||
| Total | 46.500 | 49 | ||||
| Sidewalk | Between groups | 4.234 | 2 | 2.117 | 1.992 | 0.148 |
| Within groups | 49.946 | 47 | 1.063 | |||
| Total | 54.180 | 49 | ||||
| Protective Barriers | Between groups | 0.056 | 2 | 0.028 | 0.021 | 0.979 |
| Within groups | 62.664 | 47 | 1.333 | |||
| Total | 62.720 | 49 | ||||
| Public amenities | Between groups | 1.170 | 2 | 0.585 | 0.317 | 0.730 |
| Within groups | 86.850 | 47 | 1.848 | |||
| Total | 88.020 | 49 | ||||
| Integrated public Utilities | Between groups | 2.521 | 2 | 1.260 | 0.496 | 0.612 |
| Within groups | 119.479 | 47 | 2.542 | |||
| Total | 122.000 | 49 | ||||
| Landmarks and special features | Between groups | 6.809 | 2 | 3.405 | 1.175 | 0.318 |
| Within groups | 136.171 | 47 | 2.897 | |||
| Total | 142.980 | 49 | ||||
| Overpass and Underpass | Between groups | 1.616 | 2 | 0.808 | 0.392 | 0.678 |
| Within groups | 96.804 | 47 | 2.060 | |||
| Total | 98.420 | 49 | ||||
| Shading structures | Between groups | 4.024 | 2 | 2.012 | 0.823 | 0.446 |
| Within groups | 114.956 | 47 | 2.446 | |||
| Total | 118.980 | 49 | ||||
| Atmospheric factors | Between groups | 4.281 | 2 | 2.140 | 0.885 | 0.420 |
| Within groups | 113.719 | 47 | 2.420 | |||
| Sum of squares | Degrees of Freedom | Mean square | F Statistic/value | P- value | ||
| Total | 118.000 | 49 | ||||
| Form and morphology | Between groups | 6.125 | 2 | 3.063 | 0.869 | 0.426 |
| Within groups | 165.655 | 47 | 3.525 | |||
| Total | 171.780 | 49 |
The mean value for each component from the expert and public groups is compared using t-test analysis. It can be seen that the difference of opinion in the prioritization of components occurs only for sidewalk and atmospheric factors. Carriageway and sidewalk are the components receiving top scores from both groups. Expert scoring depicts prioritization of sidewalk over carriageway, whereas public opinion concludes that carriageway should be prioritized in terms of establishing safe and comfortable streets. However, the difference in mean expert scores between carriageway and sidewalk is as low as 0.17, but that of the public score is 1.52 on prioritizing carriageway over sidewalk. Though the opinion of different user groups of the public including motorists and pedestrians with no difference as proven by the ANOVA test is to prioritize carriageway over sidewalk, experts encourage prioritizing sidewalk over carriageway. It could be assumed that the expert opinion is derived based on the literature evidence on pedestrians being the most vulnerable category of users, and the lack of standards to regularize the sidewalk design in Sri Lanka as discussed in the literature review. Further research on public opinion through interviews with on-site users could contribute to understanding the reason for the public opinion to prioritize carriageway over sidewalk. However, both components are identified as the major components of streets through literature review and on-site observation of user behaviour. Thereby it could be understood that equal priority should be provided to both carriageway and sidewalk when designing urban streets.
The public has prioritized atmospheric factors with a higher mean score than that by experts concerning determining the user's physical safety and comfort. It could be assumed that experts regard atmospheric factors as less of a physical discomfort and safety threat, while users prioritize atmospheric factors such as sound and odour as a physical discomfort. However further research is to be conducted through detailed interviews to understand the perspective of experts and the public on this component’s effect on physical safety and comfort of users.
| Component | Leven’s test for equality of variances | t-test for equality of means | Results | ||
|---|---|---|---|---|---|
| Significance value | Equal variance assumption | Significance value | There is no difference between experts and public Sig (2 tailed) > 0.05) | There is a difference among experts and public opinion Sig (2 tailed <0.05) | |
| Carriageway | 0.000 | Equal | 0.177 | X | |
| Sidewalk | 0.033 | Equal | 0.001 | X | |
| Protective Barriers | 0.000 | Equal | 0.665 | X | |
| Public amenities | 0.044 | Equal | 0.958 | X | |
| Integrated public Utilities | 0.114 | Not equal | 0.365 | X | |
| Landmarks and special features | 0.275 | Not equal | 0.372 | X | |
| Overpass and Underpass | 0.033 | Equal | 0.000 | X | |
| Shading structures | 0.054 | Not equal | 0.673 | X | |
| Atmospheric factors | 0.067 | Not equal | 0.231 | X | |
| Form and morphology | 0.654 | Not equal | 0.073 | X | |
Comparison of the hierarchy of the prioritization of street components as per the public and expert opinion:
The hierarchy of components changes only due to the difference of opinion of the two groups with regard to sidewalk and atmospheric factors, as proven above and could be understood from the hierarchy of components table below.
| Mean public score | Component hierarchy of public score | Components hierarchy of expert score | Mean expert score |
|---|---|---|---|
| 12.67 | Carriageway | Sidewalk | 15.43 |
| 12.50 | Sidewalk | Carriageway | 13.91 |
| 11.25 | Protective barriers and boundary markers | Protective barriers and boundary markers | 11.60 |
| 10.68 | Overpasses and Underpasses | Overpasses and Underpasses | 10.71 |
| 9.60 | Shading facilities | Shading facilities | 10.26 |
| 9.33 | Public amenities | Public amenities | 8.89 |
| 9.23 | Atmospheric factors | Integrated public utilities | 8.60 |
| 8.85 | Integrated public utilities | Form and morphology | 7.51 |
| 8.26 | Form and morphology | Atmospheric factors | 6.66 |
| 7.63 | Landmarks and special features | Landmarks and special features | 6.43 |
A street is both a pass-by ‘link’ as well as a ‘place’ to stay (Forsyth, 2015). Comfort and attractiveness which are prominent in determining the walkability of streets are found absent in Asian cities, as priority is given only to safety and accessibility which are comparatively low-level needs (Nakamura, 2021). However, all factors relevant to comfort, attractiveness, safety, and accessibility must be prioritized in designing urban public streets to facilitate efficient usage.
Carriageway: At all three streets, the carriageway conforms to the minimum width specified as per the Geometric Design standards by the Road Development Authority Sri Lanka (1998). Problems such as uneven surfaces and inefficient draining of stormwater are observed. Such stagnation of water due to construction or maintenance error causes discomfort to both drivers, as well as pedestrians on the sidewalk due to the splashing of water. Illumination is recorded using an illuminometer and was less than the standard minimum value of 25 Lux on average. However, no other severe problems are noticed. The availability of a well-defined carriageway as in the case studies is mandatory to ensure safety and comfort.
Sidewalk: The uneven surface of paving causes stagnation of stormwater, which could also cause skidding of users. Tactile surfaces are present to direct visually impaired persons. The minimum width is measured as 1.2m, confining to standards (Design Build, 2004 & 2018). However, sidewalk construction errors are not observed to directly affect motorists/vehicular users. Availability of a minimum width of sidewalk is mandatory to ensure safety and comfort.
Protective barriers and boundary markers: No protective barriers are found to separate sidewalk and carriageway to ensure safety or to prevent pedestrians from crossing at inappropriate locations at all three streets. This causes discomfort and threat to both pedestrians and motorists. Protective barriers are mandatory in an urban street separating the sidewalk and carriageway to ensure the safety of pedestrian.
Overpasses and Underpasses: The presence of a pedestrian overpass could allow for a continuous flow of vehicles and ensure the safety of pedestrians crossing. As underpasses and overpasses are not present at the chosen case study streets, the pedestrian underpass at Havelock Street, Colombo-05 is studied. As per the observation, the absence of pedestrian crossing at carriageway encourages the motorists to drive at higher speeds which could cause a threat to pedestrians at sidewalks due to mishaps.
Shading facilities: No furniture zone or seating zone is observed at any streets. Streets with high-rise buildings or trees frequently on either side do not necessarily require shading devices. Therefore, this component is not mandatory.
Public amenities: Transit shelters are available at a few locations, and these structures satisfy minimum ergonomic requirements to ensure comfort. However, a clear distance from carriageway, access to the disabled, and illumination have not been adequately provided for satisfactory comfort and safety. Waste receptacles are not provided at any of the streets. This component is a context-specific requirement, although an adequate number of waste receptacles should be present continuously at equal distances.
Atmospheric factors: Noise and odour are atmospheric factors that affect physical safety and comfort. Although these factors are within comfortable and safe limits on the day of assessment, the traffic in the contemporary pandemic situation is lower than normal.
Integrated public utilities: The utility boxes and lines are observed to be placed closer to buildings, and utility poles obstructing the carriageway and sidewalk are observed at case study streets. This could be a major threat to the physical safety of users, leading to severe injuries, and even deaths.
Form and morphology: Overall compositions of the streets are in general legible, with no unsafe niches, thereby ensuring safety and comfort. All the components when composed appropriately contribute to the achievement of a safe and comfortable form and morphology.
Landmarks and special features: A landmark is found only at the Galle Road assessment area. The statues at the centre island at the junction of Kollupitiya, do not cause physical discomfort or threat to the users. No screening views or obstruction of throughways were observed. The presence of this component is optional, where it would affect the physical safety and comfort only when present in an inappropriate way but does not contribute to enhancing physical safety or comfort.
From the above-summarised case study description of each component, the contribution of each component in determining safety and comfort is analysed. Components are categorized as per Table 7 based on the analysis of the case study as well as expert and public scoring on the prominence of components in determining physical safety and comfort of users.
| Mandatory components to ensure physical safety and comfort | Components that enhance the physical safety and comfort when present | Components that affect the physical safety and comfort when present |
|---|---|---|
|
Sidewalk Carriageway Protective barriers and boundary markers |
Overpasses and underpasses Shading facilities Public amenities Atmospheric factors Integrated public utilities |
Form and morphology Landmarks and special features |
The first outcome of this research on identified components of urban public streets that ensure physical safety and comfort to all users in urban public streets is a comprehensive outcome that combines most components included separately in existing several street assessment models. Thus, this becomes a comprehensive set of components. The second outcome comparing the perspectives of the public and experts is also novel in the context of urban public street components and reveals that there is a difference of opinion in the prominence of sidewalks and atmospheric factors. This study further approves the contemporary sustainable development goals emphasising active transport that requires attention towards efficient sidewalks, and environmental factors focussing on atmospheric factors. The third outcome on categorized components based on their prominence is a novel outcome that has not been statistically analysed in any existing literature.
The conclusion is derived based on the above analysis of public and expert scoring as well as a case study of the streets of Colombo. Carriageways, sidewalks, and protective barriers and boundary markers that are provided higher scores by both expert and public groups, and observed as vital through case study are mandatory components that should be available in any street to ensure safety and comfort. The presence of these elements, which adhere to ergonomic standards is an additional advantage. Therefore, these components should be highly prioritized when designing any street. Overpasses and underpasses are not mandatory components for all streets. However, when present for access either by pedestrians or motorists, they should serve a similar accessible function as the carriageway or sidewalk. Therefore, underpasses and overpasses are important to be prioritized next in the hierarchy when designing, when they are present. Shading facilities, public amenities, atmospheric factors, and integrated public utilities are components that are within the zones of either carriageway or sidewalk that are not mandatory to ensure safety and comfort, but in their presence would influence or elevate the physical safety and comfort. Therefore, when these components are present, it is important to ensure their ergonomic standards and demand for the location. ‘Form and morphology’ is a component that is a result of the composition of all the above components in ensuring safety and comfort. 'Landmarks and special features' are neither a mandatory component of the street nor do they enhance physical safety and comfort. However, their presence could influence physical safety and comfort, and therefore it is necessary to consider the scale, material quality and design features of such components.
Thereby, it could be concluded that it is ideal to group the identified street components based on expert and public opinion as well as case study analysis as per Table 7– based on their necessity of availability, and contribution to achieving physical safety and comfort, to identify the hierarchy of priority in designing. This categorized prominence of components helps plan the development of urban streets in different phases, especially in developing countries with limited funds. In addition, an important finding is the difference of opinion between experts and the public on the priorities of sidewalk and atmospheric factors. This finding further contributes to conducting research to analyse the reason for such differences. Such difference of opinion among experts and the public is vital to be identified regarding every public realm such as parks, plazas, squares etc. to carry out sustainable development. This research methodology sets precedence to conduct surveys in different contexts. This research outcome on the prominence of components sets the basis to develop a model to assess the safety and comfort of users at urban public streets similar to sustainability assessment models such as ‘The International Road Assessment Programme’ for roads and the LEED rating system. The outcome of prominent components contributes to verifying the availability of standards and design guidelines relevant to the components and combining them as one comprehensive document contributing to efficient planning.
Conceptualization, A. Kumaraguruparan., K.W.J.P. WIjesundara. and U.G.D, Weerasinghe.; methodology, A. Kumaraguruparan., K.W.J.P. WIjesundara. and U.G.D, Weerasinghe..; software, A. Kumaraguruparan.; investigation, A. Kumaraguruparan.; data curation, A. Kumaraguruparan.; writing—original draft preparation, A. Kumaraguruparan.; writing—review and editing, A. Kumaraguruparan., K.W.J.P. WIjesundara. and U.G.D, Weerasinghe.; supervision, K.W.J.P. WIjesundara. and U.G.D, Weerasinghe. All authors have read and agreed to the published version of the manuscript.
The authors declare that they have no conflicts of interest regarding the publication of the paper.
This work is supported by the Accelerating Higher Education Expansion and Development (AHEAD)- DOR Grant affiliation with Ministry of Higher Education & University Grants Commission.
This research was funded by the World Bank.
