Silberstreif literally translates to "silver streak" or "silver stripe," but it's most commonly used in the idiom "ein Silberstreif am Horizont" which means "a silver lining on the horizon."
In the song, Adel Tawil uses this beautiful and hopeful image to represent a glimmer of hope or a sign of better times to come, even when surrounded by urban desolation and coldness. It's a poetic and uplifting word that perfectly captures the song's theme of finding hope amidst despair.
"Silberstreif" pictures a city that has burned itself out — hot air, abundance nobody shares, strangers who never touch, rain washing the chalk marks off cold asphalt. It's an image of urban overload: too many people, not enough warmth, tanks in the street instead of comfort.
Against that, Adel Tawil sets one small act of hope: grabbing someone's hand and racing out of the concrete desert, past the noise and the tension, toward a silver lining on the horizon. The verses about the wind, the clear water and forests blooming again describe the place he's racing toward, not the one he's in.
The title itself is the point — a "Silberstreif am Horizont" is the German idiom for a silver lining, and the whole song is that idiom turned into a literal escape: however bad the city gets, there is still a bright edge in the distance worth driving for.