Bridge Accident

Mackinac, MI

Background: During a period of gusting winds, a Yugo automobile was blown over the side of the Mackinac bridge (the bridge connecting the lower and upper peninsulas of Michigan). Allegations were made that the design of the bridge and the Yugo, as well as the operating authority of the bridge, were at fault.

What We Did: Analysis and simulation showed that during the accident sequence, the driver had performed a single lane change maneuver just at the moment that a gust of wind (wind speeds are continuously recorded at the bridge) amplified her control inputs. Using the aerodynamic properties of the car and the tire/bridge grate coefficient of friction value obtained via experiment, it was shown that the accident could have occurred with many other vehicles, and that the Yugo design was not at fault.