AASHO Road Test

The AASHO road test was to study the performance of pavement structures of known thickness under moving loads of known magnitude and frequency.

The AASHO road test introduced many concepts in pavement engineering, including the load equivalency factor.

Since panel ratings are expensive, a substitute key parameter present serviceability index (PSI) was established.

For a vehicle traveling at speed, SV is the exciting source to vertical acceleration; the second derivative in time domain of height.

This makes very good sense, since 1 – 80 Hz acceleration is the parameter used when relating human exposure from vibration to perceived discomfort in the ISO 2631-1 (1997) standard.