Developing A Causal Loop Diagram to Reduce Road Congestion in Kuala Lumpur, Malaysia: A System Dynamics Approach

Abstract

Road congestion has long been an issue plaguing urban areas, including Kuala Lumpur, the capital city of Malaysia. Accordingly, one of the strategies to reduce road congestion, as suggested by the experts, is road pricing, which is successfully practiced in several big cities around the world. Road pricing is a direct charge levied against drivers to reduce the number of private vehicles during peak hours. However, policymakers remain doubtful of its success in effectively reducing road congestion in Kuala Lumpur. In this regard, this study aims to identify the causes and effects related to road pricing implementation to reduce road congestion. To fulfil that, a causal loop diagram (CLD) model based on the system dynamics (SD) approach is developed by considering four significant causal relationships, namely the degree of road congestion, driving attraction, public transport, and road pricing charge. In developing CLD, a curved line with an arrow is created to represent the causal relationship that links one variable to another variable. Every link in the diagram must be labelled with polarity, whether positive or negative. Subsequently, the feedback loop is indicated in two types: either the reinforcing loop or the feedback loop based on the number of negative polarities. As a result, road pricing, road congestion, and driving attraction turn into a reinforcing loop where the changes in these loops could drastically affect the whole system. From the managerial perspective, this research helps highway stakeholders in Malaysia make better decisions by having a holistic view of road pricing implementation for a better metropolitan lifestyle.