Why does xenon gas light stronger more than ordinary lamp in modern front cars

Good question! The xenon lamps use high intensity discharge technology, in which no filament is heated. This means more eletrical energy is converted into light without much loss to heat compared to incandescent light bulbs. If you want to know why xenon headlights are so annoyingly and painfully bright and blinding -- this is because only a few people in the US bother to align them properly on their cars. In Europe, proper alignment is a law. Good for them!