Effect of signal head location on stop-line encroachment

Abstract EN

A common concern among traffic police officials in Saudi Arabia is the fact that drivers encroach on the area beyond the stop-line while waiting on red at signalized approaches.

In a measure to prevent this from occurring, officials have removed the far-side signal head, leaving only the one on ءه near-side, arguing that drivers will be able to see the signal only if they stop upstream of the near-side signal head while waiting on red.

This study tested this argument by comparing stop-line encroachments at approaches with near-side only signal heads with those having near and far-side configurations in Dammam, a city on Saudi Arabia’s east coast.

This study concluded that encroachments are significantly higher in the first case than in the second, suggesting that, for the study approaches, this measure has exacerbated, rather than helped, the situation in the study sample.

It seems that the existence of the far-side signal head enforces the law in that it deters drivers from encroaching the area beyond the stop-line.

Further study of this phenomena is recommended.