The HID headlamp light sources (bulbs) offer substantially greater luminance and luminous flux than halogen bulbs — about 3000 lumens and 90 mcd/m2 versus 1400 lumens and 30 mcd/m2. If the higher-output HID light source is used in a well-engineered headlamp optic, the driver gets more usable light. Studies have demonstrated drivers react faster and more accurately to roadway obstacles with good HID headlamps rather than halogen ones. Hence, good HID headlamps contribute to driving safety.

Efficacy and output

HID burners produce more light from less power than halogen bulbs. The highest-intensity halogen headlamp bulbs, H9 and HIR1, produce 2100 to 2530 lumens from approximately 70 watts at 13.2 volts. A D2S HID burner produces 3200 lumens from approximately 42 watts during stable operation. The reduced power consumption means less fuel consumption, with resultant less CO2 emission per vehicle fitted with HID lighting (1.3 g/km assuming that 30% of engine running time is with the lights on).

Longevity

The average service life of an HID lamp is 2000 hours, compared to between 450 and 1000 hours for a halogen lamp.