In an emergency with a vehicle going into the water, you only have seconds to act. Maybe someone cuts you off while you're driving near a river, for instance. You swerve to avoid them, make contact anyway, and lose control of the car. It winds up in the water.
Based on size and weight alone, semitrucks pose a significant danger to smaller passenger cars. When those massive trucks also lack adequate braking systems, they can become even more of a highway hazard. Unfortunately, many highway truck crashes result from brake failure issues, and when a truck loses its brakes, it can lead to serious injuries and even death.
When someone says that they were "ran off of the road," the phrase makes it sound deliberate, like it was part of a road-rage incident. While that certainly does happen in Ohio, it's important to remember that you can also get ran off of the road by someone who is simply not paying enough attention to what they're doing.