Here are reputable U.S. truck / commercial transportation insurance brokers and who they tend to serve best — quick one-line notes and sources so you can research or contact them:

• Reliance Partners — specialty transportation broker focused on owner-operators, small fleets and larger carriers; strong trucking-focused programs and digital tools. (reliancepartners.com)
• Transtar Insurance Brokers — long-running broker (since 1963) that specializes in owner-operators and for‑hire motor carriers. (transtarinsurance.com)
• HUB International — large national broker with a dedicated commercial transportation practice and broad carrier access. (hubinternational.com)
• Arthur J. Gallagher (AJG) — global broker with a transportation & logistics practice that handles asset-based carriers, brokers, last‑mile and specialty trucking exposures. (ajg.com)
• Marsh / Marsh McLennan — major broker with transportation & logistics programs for fleets, brokers and complex networks. (marsh.com, marshmma.com)
• NFP — national broker with a transportation specialty team that handles trucking, cargo and fleet programs. (nfp.com)
• Lockton — large independent broker with an experienced transportation & logistics practice for mid‑to‑large fleets. (global.lockton.com)
• Brown & Brown — national broker with transportation industry teams and program design for trucking. (bbrown.com)
• AmWins — wholesale/binder and program specialist used by retail brokers for hard-to-place trucking risks and niche programs. (amwins.com)
• SmartFinancial (and similar aggregators) — useful if you want one form to compare quotes from many brokers/carriers quickly (good for owner-operators or small fleets). (smartfinancial.com)
• OOIDA (Owner‑Operator Independent Drivers Association) — membership organization that also offers owner-operator–focused insurance programs and benefits. (ooida.com)

Quick checklist for choosing the right broker (based on common expert guidance):

• Work with brokers that specialize in trucking/transportation (they understand FMCSA/DOT requirements, cargo limits, endorsements). (transtarinsurance.com, marsh.com)
• Get multiple quotes and compare total cost of risk (premiums + deductibles + service/claims handling). (smartfinancial.com, nerdwallet.com)
• Ask which carriers the broker places with and check those carriers’ financial strength (AM Best) and claims reputation. (nerdwallet.com)
• Confirm claims/claims‑advocacy process, certificate/filing turnaround, and whether they handle BMC filings and state/federal compliance. (global.lockton.com, hubinternational.com)
• For owner-operators: ask about non‑trucking/bobtail, occupational accident, trailer interchange, and motor‑truck cargo limits and endorsements. (ooida.com)

If you want, I can: (a) narrow this to brokers that serve your state, (b) pick the best options for an owner‑operator vs. 1–5 truck fleet vs. 50+ truck fleet, or (c) produce a short email script you can send to 3 brokers to request quotes and required documents. Tell me which of those (or which state/fleet size) and I’ll prepare it.