Most studies concerned with the influence of on-street bike lanes on safety rely on crash data for evaluation, but a study from researchers at the University of Waterloo examined the lateral separation (passing distance) between motorized vehicles and cyclists when the motorized vehicles were passing the cyclist.  The study, which primarily focused on four-lane urban arterials with/without exclusive bike lanes where the maximum posted speed limit was 50 km/h (31 mph), finds that roadways with exclusive bike lanes result in greater separation between bicyclists and motor vehicles, as compared to roads with no bike lanes. In addition, unsafe passing maneuvers (defined as passing distances of less than 1,000 mm, or 39 inches) were observed less frequently on the facilities where exclusive bike lanes were present.  Furthermore, when bike lanes were not present, a much higher proportion of vehicles passing cyclists move laterally (to their left) and encroach upon the adjacent lane, resulting in higher number of potential conflicts between motor vehicles on both two- and four-lane facilities.