Although bicycles generally move at speeds considerably slower than vehicle traffic on Indiana roadways, cyclists have the right to ride in the vehicle lane, and they are subject to all the rules of vehicle traffic. Motorists who "get stuck" behind a bicycle in traffic may be impatient waiting for a chance to pass. Unfortunately, many of them may attempt to squeeze by when there is traffic in the oncoming lane. This puts the cyclist at high risk for a sideswipe or other collision.
According to Indiana Online Driver Improvement, it is not safe to pass a bicycle any closer than three feet. In addition, drivers should not follow closely while waiting for the opportunity to pass. It may be difficult to judge the bicycle's speed, so they should look over their shoulder to make sure they have provided enough space between the vehicle and the bicycle before they move back into the lane.
The National Conference of State Legislatures notes that it is so dangerous to give less than three feet of space to a bicycle when passing, 27 states and the District of Columbia have passed laws requiring it. Pennsylvania requires four feet of space, and in South Dakota, if a vehicle is moving above 35 mph, it must not pass within six feet of the bicycle. Other states simply require that a motorist allows a "safe distance" between the vehicle and the bicycle.
Despite all the recognition from legislators across the United States regarding the need for bicycle safety, Indiana has not adopted a passing law of any kind.