<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=windows-1257"> <META content="MSHTML 6.00.6000.16762" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY> <DIV><SPAN class=mw-headline><FONT face=Arial size=4><STRONG>Disadvantages</STRONG></FONT></SPAN></DIV> <DIV> <P><A id=Glare name=Glare></A></P> <H5><SPAN class=mw-headline><FONT face=Arial>Glare</FONT></SPAN></H5> <P><FONT face=Arial size=2>Vehicles equipped with HID headlamps are required by </FONT><A title="World Forum for Harmonization of Vehicle Regulations" href="http://en.wikipedia.org/wiki/World_Forum_for_Harmonization_of_Vehicle_Regulations"><FONT face=Arial size=2>ECE regulation 48</FONT></A><FONT face=Arial size=2> also to be equipped with headlamp lens cleaning systems and automatic beam levelling control. Both of these measures are intended to reduce the tendency for high-output headlamps to cause high levels of glare to other road users. In North America, ECE R48 does not apply and while lens cleaners and beam levellers are permitted, they are not required; </FONT><A title="" href="http://en.wikipedia.org/wiki/Headlamp#cite_note-20"><FONT face=Arial><FONT size=2><SPAN>[</SPAN>21<SPAN>]</SPAN></FONT></FONT></A><FONT face=Arial size=2> HID headlamps are markedly less prevalent in the US, where they have produced significant glare complaints.</FONT><A title="" href="http://en.wikipedia.org/wiki/Headlamp#cite_note-NHTSA_8885-21"><FONT face=Arial><FONT size=2><SPAN>[</SPAN>22<SPAN>]</SPAN></FONT></FONT></A><FONT face=Arial size=2> Scientific study of headlamp glare has shown that for any given intensity level, the light from HID headlamps is 40% more glaring than the light from tungsten-halogen headlamps.</FONT><A title="" href="http://en.wikipedia.org/wiki/Headlamp#cite_note-Vanderlofske-22"><FONT face=Arial><FONT size=2><SPAN>[</SPAN>23<SPAN>]</SPAN></FONT></FONT></A></P> <P><A id=Mercury_content name=Mercury_content><FONT face=Arial size=2></FONT></A></P> <H5><SPAN class=mw-headline><FONT face=Arial>Mercury content</FONT></SPAN></H5> <P><FONT face=Arial size=2>HID headlamp bulb types D1R, D1S, D2R, D2S and 9500 contain the toxic </FONT><A class=mw-redirect title="Heavy metals" href="http://en.wikipedia.org/wiki/Heavy_metals"><FONT face=Arial size=2>heavy metal</FONT></A><FONT face=Arial size=2> </FONT><A title="Mercury (element)" href="http://en.wikipedia.org/wiki/Mercury_(element)"><FONT face=Arial size=2>mercury</FONT></A><FONT face=Arial size=2>. The disposal of mercury-containing vehicle parts is increasingly regulated throughout the world, for example under </FONT><A class="external text" title=http://www.epa.gov/epaoswer/hazwaste/id/univwast/lamps/lamps.htm href="http://www.epa.gov/epaoswer/hazwaste/id/univwast/lamps/lamps.htm" rel=nofollow><FONT face=Arial size=2>US EPA regulations</FONT></A><FONT face=Arial size=2>. Newer HID bulb designs D3R, D3S, D4R, and D4S which are in production since 2004 contain no mercury</FONT><A title="" href="http://en.wikipedia.org/wiki/Headlamp#cite_note-23"><FONT face=Arial><FONT size=2><SPAN>[</SPAN>24<SPAN>]</SPAN></FONT></FONT></A><FONT face=Arial size=2> </FONT><A title="" href="http://en.wikipedia.org/wiki/Headlamp#cite_note-24"><FONT face=Arial><FONT size=2><SPAN>[</SPAN>25<SPAN>]</SPAN></FONT></FONT></A><FONT face=Arial size=2>, but are not electrically or physically compatible with headlamps designed for previous bulb types.</FONT></P> <P><A id=Lack_of_backward-compatibility name=Lack_of_backward-compatibility><FONT face=Arial size=2></FONT></A></P> <H5><FONT face=Arial> <SPAN class=mw-headline>Lack of backward-compatibility</SPAN></FONT></H5> <P><FONT face=Arial size=2>The arc light source in an HID headlamp is fundamentally different in size, shape, orientation, and luminosity distribution compared to the filament light source used in tungsten-halogen headlamps. For that reason, HID-specific optics are used to collect and distribute the light. HID burners cannot effectively or safely be installed in optics designed to take filament bulbs; doing so results in improperly-focused beam patterns and excessive glare, and is therefore illegal in almost all countries.</FONT><A title="" href="http://en.wikipedia.org/wiki/Headlamp#cite_note-25"><FONT face=Arial><FONT size=2><SPAN>[</SPAN>26<SPAN>]</SPAN></FONT></FONT></A></P></DIV> <DIV><BR><FONT face=Arial size=2>-- <BR>Dainius</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2></FONT> </DIV></BODY></HTML>