State Route 58 is a freeway from its south junction with SR 99 in Bakersfield (the West Bakersfield Interchange) to several miles east of Mojave (a freeway bypass of Mojave was completed in 2004), except for two at-grade intersections apart in the Caliente area. Other freeway segments are bypasses of Boron, Kramer Junction (a freeway bypass of Kramer and Kramer Junction was completed in 2019), and Barstow. Except for the Boron-Kramer Junction freeway bypass, SR 58 is primarily a four-lane expressway (two lanes per direction) from just east of Kramer Junction up to the Barstow bypass segment.