Combining environmental quality assessment of bicycle infrastructures with vertical acceleration measurements

Abstract

Growing interest in zero emission transport modes, such as cycling, is currently generating motivation to construct new cycle paths. However, transportation planners and managers cannot always rely on practical methods for allocating the resources (often limited) needed for inventories and assessing cycling infrastructures. The aim of this study is to develop a method for classifying cycle paths in terms of roughness and general conditions of the pavement surface. Inventory data and information regarding the infrastructure conditions were collected on-site using video recordings taken by an action camera directly mounted on a bicycle. Georeferenced vertical acceleration data were collected using a smartphone. Acceleration data of three different pavement surfaces (asphalt, concrete and concrete bricks) were registered. The results showed the lowest acceleration values for concrete pavement and the highest values for interlocking concrete pavement. The proposed method can be a practical and efficient approach to evaluate cycling infrastructures in terms of pavement condition.

Introduction

Traffic congestion, noise and air pollution are nowadays common issues in urban areas. As these growing problems are all strongly associated with motorized transport modes, cycling is becoming an attractive alternative for urban transportation. The success of cycling as a viable transport mode depends, however, on the conditions of the infrastructure, given that safety and comfort are essential to attract new users (Dill and Carr, 2003, Pucher and Buehler, 2007). In addition, proper maintenance of cycling infrastructures is equally important for the different parties involved in urban planning and management of public financial resources.

With the expansion of transport infrastructure management systems, database integration has become a sensitive matter for managers and government agencies. GIS (Geographic Information Systems) tools are highly potential in terms of facilitating these integration processes due to the capacity of combining geographical characteristics with tabular data. The inventory phase, for example, which is essential in infrastructure management systems, can clearly benefit from GIS tools. Data collection and analysis at a network level, which is extremely useful for planning, programming, budgeting, operational management, assessing and identifying potential points for improvement, is another interesting application of GIS for transport infrastructure management systems (Haas and Hudson, 2015). Nevertheless, despite the importance of the inventory phase, Nuñez and Rodrigues da Silva (2016) found in the literature that data collection is often exclusively based on questionnaires conducted with users and subjective criteria.

Even though management systems for cycling infrastructures are not very common yet, Gharaibeh et al. (1998) developed a cycle path management system at the University of Illinois in the USA almost two decades ago. The system inventory includes information about the general characteristics of the infrastructure, as well as assessment reports of the pavement conditions based on field data. Physical characteristics of the paths, such as surface defects, painting and rolling conditions, vertical displacements, geometry, etc., are classified on a severity scale with five levels. The system is well designed, but it relies on visual inspections and users’ subjective assessments of the rolling conditions. It does not include objective measurements of vibrations, environmental comfort or any other variable of the physical environment around the infrastructure.

Given the difficulties and even risks of accidents that pavement surfaces in poor conditions can cause to cyclists, this study proposes an alternative method to assess the pavement conditions on cycle paths. Data for the inventory and assessment of the conditions of this important infrastructure element are collected using a smartphone and a video camera. The vertical acceleration data are transferred to a GIS package and subsequently used for a comprehensive analysis, as well as with other variables related to the cyclists’ comfort and environmental attributes around the cycle paths (video recorded).