The halogen headlights on most vehicles are inappropriate for speeds greater than 40mph according to the National Institute of Highway Safety. Only OEM LED & HID OEM + AFM Kits achieve better than Halogen performance.
Luminous Flux Density advantage held by OEM HID optics + arc lighting 35w, the best spectral performance with the greatest foot candle lumens projected.
LED in OEM installations achieves good DRL functionality, but LED replacement bulbs offer a compromised solution that must be fan cooled to endure, which also does not produce light in the same tight photon packet space as a halogen or HID. The position and emission angle of the lumens from LED headlights means they do not interact with the OEM reflector in a way that produces good spectral output characteristics.
Latest generation LED headlights utilize the Cree MK-R LED modules at 1769 lumens each, in pairs to achieve the 9003 / H4 configuration. When utilized in other bulb formats the LED emitters do not produce an geometric photon genometry match with the OEM reflector assembly, which gives rise to an irregular photon emission pattern that does not create uniform lighting.
Our 2005 Toyota Prius II and 2014 Honda CR-z ex utilize HID as the low beam lighting technology, a well proven solution, the arc flux packet of the HID matches the position geometry of halogen filiments, enabling the reuse of well refined reflector designs originally developed for halogen bulbs to be easily adapted for HID.
HID contains mercury, a neurotoxic metal liquid that become metallic gas when heated, inside an HID bulb arc heating for example. The vaporized mercury becomes an ionized gas where in electricity both heats and excites the gas into an electrically conductive plasma.
Lumen depreciation affects all lighting technologies. LED, HID, Incandescent and Halogen bulbs all suffer from a gradual loss in output over their functional life.
After conducting extensive research on LED technology, I can tell you that no commercially available LED headlight replacement bulbs match the photon emission geometry that would result in good headlight performance. With 4000 lumens, LED can outperform 1600 lumen halogen bulbs, but the 3600 lumen output of the 35 watt HID creates a better bulb replacement because its photo emission geometry approaches that of the Halogen Filiment optics designs present in the headlight you are retrofitting, like the H4 assembly in our 1993 Subaru Legacy L, an inherited gift that once belonged to the late Ken Schwarz, my amazing father who helped me to become who I am today!
Very expensive LED aftermarket kits are able to beat HID in terms of lumen performance, the lack of geometrical alignment in the luminous flux, the 55W HID gives the best net performance as a retrofit in a halogen headlamp assembly.
The HID still reigns supreme as the proven electrically noisy solution, soon to be replaced by next generation LED' technology in 2019 or beyond. For now we have OEM LED & HID as the best vehicle light technologies. Future LED tech will blow the lumens off the current generation of products. Raman Emitter Headlights will become available when most new cars come with autopilot as a standard feature. Today all the automakers are dumping billions into self driving car technology. With synthetic vision as a big part of emergent A.I. better forward lighting technology will continue to be appreciated, even if not in the visible spectrum for the self driving cars specialized cameras & sensors.
Lighting technology becoming revolutionized by intelligent control, motion sensor, auto on off, intelligent sensing, is not the individual elements of a system is the architecture of how they are connected that makes the big difference. The same can be said of people, and how we are all connected to systems, chemical systems, each other, our genome, a cultural history
Current generation LED technology is hindered by high temperature operation constraints that must be air cooled at high current pumping levels of high output LED modules like the CREE MK-R or XML2~ Elaborate copper heatsinks are required for LED, with fan cooled aluminum doing the heavy thermal evacuation duty. Heat thereby produced increasing the entropy in the world. All uses of energy are increasing entropy, so that human can organize the chemistry of existence with ever greater intelligence, artificial intelligence emerging as an echo of natural intelligence emergence, a self reinforcing system of intelligence optimization and enhancement, we already live in the information age driven by our minds, connected by powerful ideas, across space and time to everyone who is an to many who are no longer. We are each temporary, fragile being running out of time. The future of medicine might be able to save us from a biological clock limitation due to natural aging death, genetic engineering like CAS9 & CRISPR paving the way for life extension technology, the cure for all diseases and the way towards everlasting biological chemical energy life with supreme intelligence.
When automakers design a headlight, they are investing serious engineer expenses, and capital of up to $20000 in photometric analysis studies, weather, aging, durability and electrical & thermal safety. Sometimes a drop in bulb conversion kit will not work properly with the original headlamp assembly because of spectral output misaligning, photon emission geometry changes, and the difference between the original OEM bulb output matched to the housing and an aftermarket bulb that was not optimized to work with a given headlight assembly. Aftermarket LED headlamp bulbs are replacement bulbs that compete against HID kids for improved light output that results in better forward illumination.