Level of Service (LOS) is a widespread concept in engineering. On an easily understandable A-F scale, it ranks how smoothly (motorized) traffic moves along a street or through an intersection. Level “A” is a free flow — like an empty freeway — while Level “F” is defined as the “breakdown of flow”, which might mean stop-and-go traffic, or waiting through multiple cycles of a traffic signal.

Historically, LOS and bicycling have not always been compatible concepts. Maintaining adequate LOS on Washington Avenue, for example, was one of the barriers to reducing that street to five lanes to make room for a bikeway. Concerns that a breakdown of flow would result — LOS E or F — have thus far prevented road diets on streets like Lyndale Avenue or Franklin Avenue.

But as I learned in a webinar by the Association for Pedestrian and Bicycle Professionals (hosted by TLC), the concept of LOS is being expanded to take into account bicycle and pedestrian service.