Design of Digital Dynamic Speed Governor for Public Service Vehicles in Kenya

Abstract

The increase in road accidents on Kenyan roads led NTSA to introduce digital speed governors in public service vehicles. Several companies have created various designs of speed limiters to help alleviate this problem. However, statistics from NTSA show that there is an increase in the number of road accidents and fatalities. According to the NTSA road crash reports for 2019/2020, there was a 5.8% increase in fatalities as of October 31st, 2020, which is a clear indication that despite the adoption of speed limiters, there is a major increase in fatalities and casualties. The existing speed limiters only limit the vehicle's speed at 80KM/H. This means that a vehicle may still be moving at 80KM/H in an area designated for a lower speed limit. A good example would be in townships, where the speed limit should not exceed 30KM/H. Therefore, this is a significant risk and creates a high possibility of an accident happening. This research study focuses on how to use various technologies including GPS, GPRS, and MQTT to allow the speed governor to limit the speed dynamically according to location. A GPS receiver will get the location of the device, GPRS will connect to the cloud and download speed limit information, and MQTT will function as the communication protocol between the device and the server. In this study, the vehicle’s speed sensor will detect the speed of the vehicle. The sensor outputs a square wave signal at different frequencies dependent on the speed of the vehicle. Speed limiting will be done using the Electronic Throttle Control mechanism. This study will review and evaluate existing speed limiters used in Kenya. In the review, the study will outline the shortcomings of the existing speed limiters. This study will conduct an evaluation of the dynamic speed limiter that will be prototyped and the results will be documented.