From Halopedia, the Halo wiki
Traffic Jam is the seventh track (Disc 1 Track 7) included in Halo 3: ODST Original Soundtrack, and plays in the Halo 3: ODST campaign level Kizingo Boulevard. It is composed of Look Both Ways (0:00-0:48), Street Sweeper (0:48-4:12), and Rally Point (4:12-5:50).
Look Both Ways (0:48) begins with low strings and digital chimes, much like in Lost and Unfound (from the earlier track More Than His Share). However, it leads into high strings before ending. The piece plays in the opening cinematic, when Michael "Mickey" Crespo links up with a group of UNSC Marine.
Street Sweeper (3:24) opens with brass playing a slow and solemn melody, which repeats before progressing into different variations using first species counterpoint. As the melody repeats, heavy percussion joins in, followed by cymbal clashes and more complex rhythms with the drum kit. The low strings then enter, playing short notes in a crisper melody. The melody repeats until electric guitar enter with a series of improvisations, with accompaniment strings playing the trembling melody first heard in Strong Silent Type (from The Rookie), and echoed by woodwinds. As the electric guitar improvisation swells into more complex melodies, the strings return with the trembling melody before fading out. The percussion and electric guitar then swells into a climatic end. The first section (with brass and percussion) plays when Mickey first commandeers the M808C Scorpion. The second section (with percussion, low strings, and woodwinds) plays without the brass accompaniment and electric guitar improvisation when Mickey enters New Mombasa Sector 4.
Rally Point (1:38) features heavy percussion and low strings in a slow and heavy melody, accompanied by short cues from the bass guitar. The melody repeats and transitions into the low strings and digital chimes from Look Both Ways, then fades out. The first section with heavy percussion and low strings plays when Mickey and Taylor "Dutch" Miles defend the rally point in New Mombasa Sector 10.