What is a reefer truck?
A reefer (refrigerated trailer) is an insulated semi-trailer with a diesel-powered refrigeration unit that maintains a set temperature anywhere from -20°F to +70°F. Reefers haul roughly 20% of US truckload freight and dominate the produce, frozen food, dairy, and pharmaceutical lanes.
A reefer trailer is a dry van wrapped in 3-4 inches of foam insulation with an independent diesel refrigeration unit (most often a Thermo King or Carrier brand) mounted on the trailer nose. The unit cycles air through the cargo box to hold a temperature setpoint the shipper specifies on the bill of lading — typical settings are -10°F to 0°F for frozen, 28°F to 38°F for fresh produce, 36°F to 40°F for dairy and meat, and 55°F to 65°F for pharmaceuticals. A reefer trailer costs roughly $65,000-$95,000 new (vs. $35,000-$55,000 for a dry van) and adds 1,500-2,500 lbs of tare weight, cutting legal payload to around 43,000 lbs. The reefer unit burns 0.3-0.7 gallons of diesel per hour of run time, which is often a separately reimbursable line item on the rate confirmation. Modern reefer units record continuous temperature logs that ship with the POD — most produce, meat, and pharmaceutical shippers will reject a load if the temperature log shows an excursion. Reefer drivers are also responsible for pre-cooling the trailer to setpoint before live-loading, and for setting the unit to continuous vs. cycle-sentry mode based on commodity sensitivity. Reefer rates run 10-25% higher per mile than dry van on most lanes, with seasonal spikes during produce season (March-July in California, May-September in the Pacific Northwest and Midwest).
- What temperature does a reefer truck run at?Anywhere from -20°F to +70°F, set per-load on the shipper's bill of lading. Frozen freight runs 0°F or below; fresh produce 32-40°F; dairy and meat 34-40°F; pharma 36-46°F or 59-77°F depending on drug class. The driver sets the unit and documents the setpoint at pickup; the receiver verifies temperature on arrival.
- Why do reefer rates spike during produce season?Spring through summer, the volume of fresh produce moving out of California, the Pacific Northwest, Florida, and the Mexican border states overwhelms the available reefer capacity headed in those directions. Rates on lanes like Salinas-CA to Chicago can jump 40-100% above winter levels for 6-10 weeks. Carriers position trailers into produce regions to capture the premium; once the harvest tapers, rates collapse.
- Can a reefer haul dry freight?Yes — many reefer carriers run dry on the backhaul to keep miles loaded. The trade-off is that reefer carriers usually price dry-van backhauls below market because the alternative is deadhead. Shippers booking a reefer to haul dry freight should confirm the trailer is clean and pre-cooled or pre-warmed to the dry-van norm (no condensation, no residual odors from prior temperature-controlled loads).