Ideal vehicle headlighting in the real world

Michael J. Flannagan

The University of Michigan, Ann Arbor, Michigan USA

Contact email address: mjf@umich.edu

Abstract

Various standards specify the desired photometric performance of automotive headlamps, and there has been considerable debate about what those requirements should be, both for traditional static headlamps and for new dynamic systems. However, it has long been recognized that there are significant differences between the ideal performance that is specified in headlighting standards and actual performance on the road. Currently, because of the promise of improved visibility and safety offered by adaptive headlighting systems, it is especially important to consider what differences may exist between ideal specifications and real systems, to understand why differences exist, and to determine how best to reduce those differences. In field observations, we have measured the light output of the headlamps in use by vehicles on US roads and compared those results to models based on laboratory photometry of typical headlamps and estimates of the degradation in performance that would be expected from various factors. The implications for improving traditional static headlamps as well as new dynamic systems are discussed.

Headlamps, photometry, standards, adaptive driving beam