Unlike motor-vehicle transport, the implementation of lnformation and Communications Technologies (ICT) and Cooperative Intelligent Transport Systems (C-ITS) in cycling has not been comprehensively investigated [1]. Cycling offers several benefits both to society and the environment and is one of the most sustainable and green transportation modes [2]. Many people worldwide have been switching to bicycles during the last decades, and this has increased even more due to the Covid pandemic [3]. Furthermore, the number of people who ride an e-bike is also rising [ 4]. Thus, the number of cyclists is increasing and, in turn, the number of cycling accidents is increasing too. For instance, in the Netherlands, one of the most cycling-friendly countries, 31 % of all road fatalities in 2019 were cyclists (203 fatalities), while in 2020, it was 37% (229 fatalities). One-third of these fatalities were e-bike users [5]. Despite the constantly evolving landscape of cycling and electric bike adoption, applications of new technologies in bicycles are still immature. In recent years, academic research on new technologies related to cyclists' comfort and safety is growing [6, 7, 8]. Furthermore, many studies focus on technologies affecting cyclists' road safety; however, it is unclear what type of technologies are implemented for bicycles. To the best of the authors' knowledge, a comprehensive review of such studies is lacking. Additionally, a clear definition of a 'smart bike'- a concept gaining popularity nowadays, is missing in the literature. To address this gap, the objective of this paper is two fold: 1) to review the state-of-the-art technologies implemented in bicycles to improve cyclists' safety, and 2) to propose an original classification for the levels of smartness of newly emerging 'smart bikes'.