  This paper investigates a new application of vehicular sensing: detecting and
reporting the slippery road conditions. We describe a system and associated
algorithm to monitor vehicle skidding events using smartphones and OBD-II (On
board Diagnostics) adaptors. This system, which we call the VehSense, gathers
data from smartphone inertial sensors and vehicle wheel speed sensors, and
processes the data to monitor slippery road conditions in real-time.
Specifically, two speed readings are collected: 1) ground speed, which is
estimated by vehicle acceleration and rotation, and 2) wheel speed, which is
retrieved from the OBD-II interface. The mismatch between these two speeds is
used to infer a skidding event. Without tapping into vehicle manufactures'
proprietary data (e.g., antilock braking system), VehSense is compatible with
most of the passenger vehicles, and thus can be easily deployed. We evaluate
our system on snow-covered roads at Buffalo, and show that it can detect
vehicle skidding effectively.
