In this paper we present SmartRoad, a crowd-sourced sensing system that detects and identifies traffic regulators, traffic
lights and stop signs in particular. As an alternative to expensive road surveys, SmartRoad works on participatory
sensing data collected from GPS sensors from invehicle smartphones. The resulting traffic regulator information
can be used for many assisted-driving or navigation systems. In order to achieve accurate detection and identification,
SmartRoad addresses various challenges in participatory sensing scenarios, including data unreliability/sparsity,
energy constraints, and the general lack of ground truth information. SmartRoad automatically adapts to different
application requirements by intelligently choosing the most appropriate information representation and transmission
schemes; it also dynamically evolves its core detection and identification engines to effectively take advantage of
any external ground truth information or opportunity. With these two characteristics, SmartRoad consistently delivers
outstanding performance for its road sensing tasks. We implement SmartRoad on a vehicular smartphone testbed, and deploy on 35 external volunteer users’ vehicles for two
months. Experiment results show that SmartRoad can robustly, effectively and efficiently carry out its detection and
identification tasks without consuming excessive communication energy/bandwidth or requiring too much ground truth
information.unpublishe
