The CBSA has released information regarding what travellers need to know regarding the recent tariffs.  

"All goods entering Canada must be reported to the Canada Border Services Agency. More information can be found on the “I declare” website."

"Effective July 1, 2018, certain goods originating from the U.S. are subject to a surtax of 25 per cent or 10 per cent on the value for duty in accordance with the United States Surtax Order (Steel and Aluminum) and United States Surtax Order (Other Goods)."

"For individual travellers, surtaxes will apply to those goods (goods originating from the U.S. included on the list) being imported above their personal exemption. Travellers’ exemptions allow returning Canadian residents to bring back goods up to a specified dollar limit on a duty- and tax-free basis. Exemption limits vary according to the time spent out of the country, with quantitative limits set for tobacco and alcohol products."

"The surtax is assessed and collected by the CBSA at the port of entry and made in the same way and within the same prescribed time that customs duties and taxes are paid.

More information can be found at the following links:

There are surtaxes that apply to certain goods originating from the U.S. That information is listed on the Department of Finance website.

"Vehicles manufactured in the United States that are eligible for importation into Canada will be assessed for excise tax and GST. Vehicles being imported may also be subject to costs associated with the Registrar of Imported Vehicles program and may be subject to provincial or territorial taxes when registered. Travellers planning to import a vehicle are encouraged to consult the CBSA website for relevant information."