Automatic signalling systems for control of traffic congestion
Aminah Hardwan Ahmed,
SATM School of Aerospace, Transport and Manufacturing
Cranfield University, United Kingdom
An exploratory qualitative review on automatic signalling systems to control traffic congestion, has been attempted in this paper. Google Scholar was searched using the topic itself as the search term, yielding 42 usable papers of both old and recent papers. These papers were discussed under various sections covering different systems, comparison of systems, algorithms, emergency vehicle passage, urban road network and IoT.
The review revealed predominance of papers on the signal control systems for single intersections only. One paper dealt with two intersections. A few papers which considered the whole urban road traffic networks. One specific topic was the easy and rapid passage of emergency vehicles especially ambulances.
Broadly the systems developed can be categorised as tested time-based or density based systems. But these two types were not compared. Only in the latter case, comparisons with fixed time signals were made. In most studies, apart from traffic signal control, associated variables like vehicle arrivals, queuing and inter-vehicular distance were also measured.
In spite of all these researches, no system can be straightaway adopted in any traffic context. The most appropriate few systems need to be tested and compared to select the most suitable one for the given traffic context. When this does not lead to selection of an existing system, need to research arises again. That is where the unlimited scope for future research exists on the topic.
Keywords: Signalling, Automatic, Traffic Control, Adaptive System