Sorry about both you and your friend's mishap. I've wondered about wider tires possibly providing a bit more stability. I use 28mm tires and would go to 32mm tires if they would fit. I like the softer ride of a wider tire but in addition, in my area, Rhode Island in NE USA, Spring runoff during the snow melt brings a great deal of, not only gravel, but much unidentifiable trash onto roadways. I believe wider tires are more likely to produce better control if caught by surprise riding over this stuff.