Discovering Phase Timing Information of Traffic Light Systems by Stop-Go Shockwaves

The cycle lengths and signal transition time of
Traffic Light Systems
(
TLS’s
), or known as the
Phase Timing Information
(
PTI
), play a key role in modern transportation systems. However, such information is not always available to the public. In this paper, we propose a
crowdsourcing
approach to solve this problem by exploiting the
stop and go
events, abbreviated by
SG
events, of vehicles on roads happening in front of target traffic lights. The PTI discovery problem is formulated by allowing only part of the vehicles participating in the discovery process. The proposed framework starts with discovering SG events, followed by collapsing these events over multiple signal cycles into one and calculating PTI information through a
shockwave
technique. The crowdsourcing part may be directly implemented on smartphones. The proposed framework was verified via field trials and simulations. Our simulation results showed that, even with a low penetration rate around
$3.8$
percent, the root mean square errors of the cycle length, green light and red light signal transition time of a TLS are
$0.04$
,
$1.3$
and
$5.8$
seconds, respectively. The achieved accuracy can be helpful in many PTI-enabled applications.