Identifying congested areas for implementing road pricing is a complicated task, especially as traffic speed and other census data may not be readily available before a detailed feasibility study is commissioned. In this study, we introduce a spatial approach to identify areas with road traffic congestion within cities. The results obtained are validated against the empirical traffic speed data in four Asian cities, i.e. Bangkok, Hong Kong, Kuala Lumpur, Singapore, from 2018 to 2020. Moreover, the findings are also compared with a more detailed conventional method of using job density to identify areas of high traffic congestion. The comparisons show that the spatial approach is both efficient and effective. Through applying the method to London, Milan and Stockholm, the study also demonstrates other potential empirical applications in reviewing the boundaries of existing congestion charging zones.