Field Evaluation of Laboratory Mechanical Tests

Mechanical tests performed in this laboratory to determine the ability of automotive lighting and safety devices to withstand environmental conditions are based largely on SAE specifications established many years ago. To ascertain whether these tests are still valid for present conditions, a field investigation was conducted of factory-installed (OEM) lamps and safety belt hardware on a total of 81 domestic-make vehicles in service. The devices were checked to determine the effects of dust, moisture, corrosion and heat resulting from exposure to natural environmental conditions. Evaluations for lighting devices were based on photometric measurements wherever possible; safety belt hardware was evaluated by visual examination.

In general, results indicate that the rain and spray and plastic stability tests currently in use in this laboratory are adequate in predicting field serviceability of automotive devices. The corrosion test, as presently performed, is not completely satisfactory in this regard. The existing laboratory dust test is far from adequate in predicting field service performance for lamps used on vehicles, such as pickup trucks, operating to a great extent on secondary and unpaved roads. The dust test also seems not quite severe enough for lamps on passenger vehicles in normal service. It was also found that lens abrasion, particularly in desert areas, is a more serious problem than anticipated.