California State Route 138 connects Palmdale and the Antelope Valley to Interstate 15 near Phelan, running approximately 60 miles through the high desert of San Bernardino County. It is a two-lane highway — undivided, with no median, minimal shoulders, and narrow lanes that leave virtually no margin between opposing traffic streams. It has been called “Blood Alley” by locals and emergency responders for decades, and the name was earned.
What Makes CA-138 Dangerous
The danger on Route 138 is structural. The road was built when traffic volumes were a fraction of what they are today, and it has not been significantly upgraded since. The result is a highway that handles modern traffic volumes at modern speeds on a physical design that belongs to a different era.
No Median, No Separation
On a divided highway, a driver who drifts across the centerline travels into a median before reaching oncoming traffic. Route 138 has no median. The centerline paint is the only thing separating eastbound and westbound vehicles. A driver who falls asleep, is distracted, or loses control at highway speed crosses directly into oncoming traffic.
The majority of fatalities on Route 138 involve head-on collisions — the most lethal type of vehicle crash — occurring because there is no physical barrier to prevent crossover.
No Shoulders
For commercial vehicles, the lack of usable shoulder means that a tire failure, mechanical problem, or any need to stop must be resolved on the travel lane or on marginal unpaved area adjacent to the road. On a road where traffic moves at 55–65 mph and there is no separation from oncoming traffic, a stopped commercial vehicle becomes a serious secondary hazard.
High Traffic Volume for a Two-Lane Road
Route 138 serves as an important connector between the growing communities of the Antelope Valley (Palmdale, Lancaster) and the I-15 corridor to the east. Traffic volumes have grown substantially as residential development expanded into the high desert, without commensurate road improvement. The result is higher-than-expected traffic density for a road of this design.
Desert Speed Culture
The open desert landscape and straight alignment of Route 138 creates the same psychological pressure as Montana’s Hi-Line: the road feels like it was built for speed. Passenger vehicles regularly exceed the speed limit significantly, and the resulting speed differential between law-abiding commercial vehicles and aggressive passenger vehicles creates dangerous overtaking situations on a road where oncoming traffic occupies the lane your car must enter to pass.
Fatality Statistics
Route 138 averaged approximately 10 fatalities per year before improvement projects began. For a 60-mile rural highway, this translates to a per-mile fatality rate that places it among California’s most dangerous roads. The nickname “Blood Alley” is not hyperbole.
Current Conditions and Improvements
CalTrans has undertaken improvement projects on portions of Route 138, including some section widenings and intersection improvements. However, as of the time of writing, significant stretches of the route remain in the original two-lane undivided configuration that earned the Blood Alley designation.
Check the latest CalTrans project information for current construction zone status, which may affect routing and speed.
Commercial Vehicle Guidance
Is CA-138 on Your Route Map?
Route 138 appears as a useful connector between I-5/CA-14 at Palmdale and I-15 near Cajon Pass. For commercial drivers, the time savings compared to using I-5 south to I-15 or CA-18 must be weighed against the route’s risk profile.
Consider the alternate route: For most commercial vehicles, the I-5/I-15 interchange via the Cajon Pass is a safer alternative to Route 138 as a connector, despite being longer. The reduction in head-on crash exposure is meaningful.
If You Must Use CA-138
- Drive the speed limit. The accident data on Blood Alley is dominated by speed-related crashes. Regardless of what other traffic is doing, drive the posted limit.
- Maintain maximum following distance. The lack of shoulder means that your emergency stop distance must be within your lane.
- Do not attempt to pass. Passing on CA-138 requires entering the oncoming traffic lane on a road that has averaged 10 fatalities per year. The risk is not worth the time.
- Watch for impaired and fatigued drivers. Head-on crashes on CA-138 frequently involve vehicles that have drifted across the centerline. Maintain maximum lateral position within your lane and be prepared for vehicles crossing the centerline.
- Use extra caution at dawn and dusk. Low sun angles and wildlife crossings add hazards at these hours.
Trucker Tips
- Evaluate the alternate. Before routing via CA-138, calculate whether I-5 to I-15 is viable. For many loads, the additional miles are worth the safety margin.
- If you use CA-138, stay right and slow. There is no room for error on a road this narrow with traffic moving toward you.
- Check CalTrans for current construction. Improvement projects may have changed conditions since this was written.
- Brief your dispatcher. If Blood Alley is on a regular route, dispatchers should know its risk profile and build in the time for conservative speed rather than pushing for speed on this particular stretch.