Editing Headlamp (section)

==== Color ====
The [[correlated color temperature]] of factory installed automotive HID headlamps is between 4200K while tungsten-halogen lamps are at 3000K to 3550K. The [[spectral density#Applications|spectral power distribution]] (SPD) of an automotive HID headlamp is discontinuous and spikey while the SPD of a filament lamp, like that of the sun, is a continuous curve. Moreover, the [[color rendering index]] (CRI) of tungsten-halogen headlamps (98) is much closer than that of HID headlamps (~75) to standardized sunlight (100). Studies have shown no significant safety effect of this degree of CRI variation in headlighting.<ref>{{cite journal|title=Mercury-free HID headlamps: glare and color rendering|journal=University of Michigan Transportation Research Institute|year=2006 |first1=M. |last1=Sivak |first2=Michael J. |last2=Flannagan |first3=B. |last3=Schoettle |url= http://deepblue.lib.umich.edu/bitstream/2027.42/55201/1/UMTRI-2004-37.pdf|access-date=2009-08-03 }}</ref><ref>{{cite journal |title=Ranges of stop sign chromaticity under tungsten-halogen and high-intensity discharge illumination |journal=University of Michigan Transportation Research Institute |year=1992 |first1=Michael J. |last1=Flannagan |first2=Juha |last2=Luoma |first3=A.W. |last3=Gellatly |first4=M. |last4=Sivak |url=http://mirlyn-classic.lib.umich.edu/F/?func=direct&doc_number=005511681&local_base=UMTRI_PUB |access-date=2009-08-03 |archive-date=19 October 2015 |archive-url=https://web.archive.org/web/20151019013407/http://mirlyn-classic.lib.umich.edu/F/?func=direct&doc_number=005511681&local_base=UMTRI_PUB |url-status=dead }}</ref><ref>{{cite journal |title=Colors of retroreflective traffic sign materials when illuminated by high-intensity-discharge headlights |journal=University of Michigan Transportation Research Institute |year=1989 |first1=Michael J. |last1=Flannagan |first2=M. |last2=Sivak |url=http://mirlyn-classic.lib.umich.edu/F/?func=direct&doc_number=005505889&local_base=UMTRI_PUB |access-date=2009-08-03 |archive-date=19 October 2015 |archive-url=https://web.archive.org/web/20151019013407/http://mirlyn-classic.lib.umich.edu/F/?func=direct&doc_number=005505889&local_base=UMTRI_PUB |url-status=dead }}</ref><ref>{{cite journal |title=In-traffic evaluations of high-intensity discharge headlamps: overall performance and color appearance of objects |journal=University of Michigan Transportation Research Institute |year=1993 |first1=M. |last1=Sivak |first2=T. |last2=Sato |first3=D.S. |last3=Battle |first4=E.C. |last4=Traube |first5=Michael J. |last5=Flannagan |url=http://mirlyn-classic.lib.umich.edu/F/?func=direct&doc_number=005512803&local_base=UMTRI_PUB |access-date=2009-08-03 |archive-date=19 October 2015 |archive-url=https://web.archive.org/web/20151019013407/http://mirlyn-classic.lib.umich.edu/F/?func=direct&doc_number=005512803&local_base=UMTRI_PUB |url-status=dead }}</ref>