A speaker drives at night through a hot, humid desert, past palms and scattered pools of light. The road is quiet, but the mind is not. Thoughts crowd the car and demand attention, then slip away. The odd phrase "the speed of darkness" suggests how fast and shapeless they feel.
The poem gets more tense as it goes. The seams in the road thump like a metronome on a piano nobody plays anymore, which hints at something silent or lost. The "Bedouin" dreams, wandering and dense, hit the windows like accusations, so the speaker seems troubled by guilt or regret. The poem never says exactly what about.
At the end the speaker slows down, sips warm water, and tries to stay alert. The last line, "try to see beyond your face," suggests a specific person haunts the drive. The mood is lonely, tired, and uneasy, with a stubborn effort to keep going.