Canadians appear to be making far fewer work trips, new cell phone data show. Bloomberg/Getty Images Donald Trump's trade war has had a large impact on Canadian tourism. New analysis out of the University of Toronto suggests that other areas of the US economy have taken a major hit as well. The findings underscore how the relationship between Canada and the US is under strain. The economic effects of President Donald Trump's disruptive approach to foreign policy are coming into sharper focus with a year's worth of data. As expected, a range of numbers like border crossings and hotel bookings show how Trump's trade war has killed off a large segment of Canadian tourism . But new analysis from the University of Toronto's School of Cities now shows that other areas of the economy have taken a major hit as well. Using cell phone data, researchers Karen Chapple, Yihoi Jung, and Jeff Allen documented an average year-over-year decline in Canadian visits to US cities of approximately 42%.…