Smart cities and smart public transportation are becoming increasingly important in planning and creating more sustainable cities, using information and communication technology to improve the efficiency and quality of public services. Research on smart cities and smart public transportation aims to improve city residents' quality of life by using smart and sustainable technology. The United States is the second largest country with smart cities, and 17 clusters can be used as findings, including the era of COVID-19, big data analysis, Montevideo, Uruguay, swapping challenges, public transport services, selection of mobile couriers, and sustainable urban mobility. Based on this, this topic is receiving increasing attention from researchers and academics worldwide. This can be seen from the increasing number of publications over the past few years. Bibliometric research also shows that technologies such as the internet of things (IoT), big data, and artificial intelligence (AI) are the main topics in smart cities and smart public transportation research.