The United States rely on the performance of more than four million miles of roadways to sustain its economic growth and to support the dynamic mobility needs of its growing population. The funding gap to build and maintain roadways is ever widening. Hence, the continuous deterioration of roads from weathering and usage poses significant challenges. Transportation agencies measure ride quality as the primary indicator of roadway performance. The international roughness index is the prevalent measure of ride quality that agencies use to assess and forecast maintenance needs. Most jurisdictions utilize a laser-based inertial profiler to produce the index. However, technical, practical, and budget constraints preclude their use for some facilities, particularly local and unpaved roads that make up more than 90% of the road network in the US. This study expands on previous work that developed a method to transform sensor data from many connected vehicles to characterize ride quality continuously, for all facility types, and at any speed. The case studies used a certified and calibrated inertial profiler to produce the international roughness index. A smartphone aboard the inertial profiler produced simultaneously the roughness index of the connected vehicle method. The results validate the direct proportionality relationship between the inertial profiler and connected vehicle methods within a margin-of-error that diminished below 5% and 2% after 30 and 80 traversal samples, respectively.
Use of Connected Vehicles to Characterize Ride QualityRaj Bridgelall et al.Page 3/17
INTRODUCTIONRide quality refers to the degree that a vehicle protects its occupants from factors that decrease ride comfort. The road impact factors (RIF) are uneven surfaces and anomalies such as potholes, cracks, and utility covers. The driver impact factors (DIF) are behaviors such as abrupt braking, rapid acceleration, weaving, and speeding around curves. Hence, the RIF and the DIF can induce motions and noises that cause rider discomfort. The vehicle impact factors (VIF) affect how riders perceive the disturbances from RIF and DIF. The VIF are a strong function of the vehicle suspension and handling characteristics but they can also include other factors such as features of furniture design, interior aesthetics, and entertainment. Altogether, these factors result in the overall ride quality experienced. Highway agencies narrow the definition of ride quality to the RIF and use a model of the vehicle suspension system, called the Golden Car, to standardize the VIF as a fixed suspension response that dampens vibrations from road roughness (1). The Golden Car approximates the suspension response of vehicles typical of the 1980s, which is around the time-period that practitioners agreed on the approach. Nearly all regular passenger and commercial motor vehicles, regardless of their size and weight, provide similar suspension responses because manufacturers design them to attenuate vibrations within a common range of frequencies that cause hu...