A usual traffic calming measure (TCM) to reduce vehicle speed in urban areas is the traffic
lights that turn red when a vehicle exceeds the speed limit. These traffic lights can detect if
an approaching vehicle exceeds the speed limit and, if so, stop it by means of a red light. It
is generally employed in interurban roads rather than in big cities, where the presence of
traffic lights is common. In a rural road crossing a small village, they are deployed to reduce
the risk of accidents to vulnerable road used when vehicles arriving at high speeds tend to
conflict with pedestrians attempting to cross the road.
The aim of this paper is to analyze the efficiency of this TCM, preceded by panels indicating
the vehicles’ speed, by controlling the vehicles’ speed in the A-132 road that crosses through
the village of Azazeta in the province of Álava/Araba (Spain). Different sequence of the
TCMs can be found in each direction approaching the village; in A direction, warning traffic
lights, the panel indicating the speed and the traffic light turning red; and in B direction, the
panel, the warning traffic lights and the traffic lights turning red.
However, similar results were obtained in both directions for average speeds and percentile
85 of the speed distribution at the traffic lights, and speed was reduced as motorists faced
the TCMs. However, although average speed was below speed limit (50 km/h), the percentile
85 was over it, implying that more than 26% of drivers did not respect the red light.
Moreover, after the traffic lights turning red, motorist speed up and higher values were
measured at the midpoint of the urban segment, the place where pedestrians use to cross
from one side of the village to the other one, although no pedestrian crosswalk is available.
