Ambassador Bridge

Legal Disclaimer: This information reflects Detroit cannabis law as of July 2026 and is for educational purposes only. It is not legal advice. Laws and regulations change — always verify current rules with the Michigan Cannabis Regulatory Agency or a qualified attorney. Cannabis remains illegal under federal law.

Last verified: April 2026

The Crossing

The Ambassador Bridge is a suspension bridge spanning the Detroit River between Detroit, Michigan and Windsor, Ontario. Opened in November 1929, it remained the longest suspension bridge in the world for nearly two years until the George Washington Bridge surpassed it in 1931. The bridge serves both passenger vehicles and commercial trucks.

Privately Owned by the Moroun Family

The Ambassador Bridge is unusual in being privately owned. The Detroit International Bridge Company, controlled by the late Manuel “Matty” Moroun’s family, has operated the bridge for over half a century. Private ownership has been politically controversial — the bridge generates substantial toll revenue without public-utility-rate-regulation oversight, and the company’s opposition to the publicly-owned Gordie Howe International Bridge has been a continuing theme in cross-border infrastructure politics.

2025 Crossing Volume

The Ambassador Bridge recorded in 2025 (per Bridge and Tunnel Operators Association data cited by CBC News):

3.5 million passenger crossings
1.9 million commercial truck crossings
~5.4 million total crossings

The Sarnia Surprise

In a striking 2025 reversal, the Blue Water Bridge in Sarnia surpassed the Ambassador Bridge in commercial truck volume for every month of 2025 — 2.1 million versus 1.9 million crossings — marking the first time the Ambassador Bridge had lost its top spot for cross-border truck traffic. Higher Ambassador tolls and re-routing pressures explain the shift. The Ambassador Bridge company has historically charged premium tolls compared to the publicly-owned alternatives; logistics carriers responded by routing more traffic through Sarnia.

Tolls

The Ambassador Bridge passenger toll is US$10 one-way (the highest of the Detroit-area crossings). Commercial truck tolls are based on axle count and gross weight. The toll structure has been a point of friction with cross-border commercial users for years and has contributed to the 2025 commercial-truck shift to Sarnia.

Cannabis at the Ambassador Bridge

The Ambassador Bridge Port of Entry is federal jurisdiction operated by U.S. Customs and Border Protection (CBP) on the U.S. side and the Canada Border Services Agency (CBSA) on the Canadian side. Cannabis at the Port of Entry is a federal violation under the U.S. Controlled Substances Act and the Canadian Customs Act, regardless of cannabis legality in Michigan or Ontario.

For drivers approaching the Ambassador Bridge from the Detroit side:

Do not carry cannabis or cannabis-derived products of any kind — including CBD with any THC content
CBP officers can search vehicles at their discretion
Vehicle inspections at secondary screening can include drug-detection dogs and X-ray scanners
Cannabis residue, paraphernalia, or even prior-use evidence can trigger questions and additional screening
Admissions of past cannabis use can result in lifetime inadmissibility for non-U.S. citizens (INA § 212(a)(2)(A)(i)(II))

Lifetime Inadmissibility Risk

For non-U.S. citizens crossing into the U.S. via the Ambassador Bridge, an admission of past cannabis use to a CBP officer can result in lifetime inadmissibility. CBP issued an October 9, 2018 clarification that Canadians coming to the U.S. “for reasons unrelated to the marijuana industry will generally be admissible” — but the discretion remains with the inspecting officer. Non-citizens with any cannabis-industry employment, ownership, or investment should consult a Canadian and U.S. immigration attorney before crossing. See Lifetime Inadmissibility.

The 2022 Convoy Disruption

In February 2022, the Ambassador Bridge was blockaded for nearly a week by participants in the Canadian “Freedom Convoy” protests against COVID-19 vaccine mandates. The blockade disrupted approximately $390 million per day in trade between Detroit and Windsor and contributed substantially to the renewed political momentum behind the Gordie Howe International Bridge (a publicly-owned alternative reducing single-bridge dependency). The episode is one of the most significant disruptions in the Ambassador Bridge’s history.

Maintenance and Replacement Span

The Detroit International Bridge Company has long planned to construct a second “replacement span” immediately adjacent to the existing Ambassador Bridge. The project has faced regulatory and political opposition for years; as of April 2026, the replacement span has not been built. The eventual opening of the Gordie Howe International Bridge will likely reshape the financial calculus for the Ambassador replacement-span project.

Approach Routes

The Ambassador Bridge approach on the U.S. side is via the I-75 / I-96 interchange near Mexicantown / Southwest Detroit. The Canadian-side approach is via Highway 3 (Talbot Road / Huron Church Road) in Windsor. Both approach corridors carry significant noise and air-quality burden from the heavy commercial-truck volume; the Delray neighborhood on the U.S. side and the Sandwich neighborhood on the Canadian side are most directly affected.