Information about public driving patterns was collected in three ways. 1. Chase Cars, equipped with instrumentation were used to monitor 2,500 randomly selected trips in various parts of the United States. Data relating to 11,000 miles of operation was thereby recorded and analyzed. 2. Long duration strip-chart recorders were installed in vehicles in use by the public. These devices recorded traces of speed vs. time, while the vehicles were in motion. More than 12,000 miles of driving were recorded. 3. Passive electronic recording devices were installed in selected vehicles which were in use by the public. These devices recorded the portion of miles driven within various speed bands. In this manner, more than 61,000 miles have been recorded. This study is still in progress and is intended to monitor long-term trends in customer operation.