LOS (Level of Service) is one of the most misunderstood metrics of traffic analysis.
The term is familiar to anyone who has read an EIR. LOS assigns a “grade” for intersection performance. The grades run from “A” to “F”, with “A” being most free-flowing, and “F” having the most delay.
The first misunderstanding is that LOS measures vehicles, not people. So a delay to a bus with 40 passengers counts the same as an SOV. Most environmentalists are aware of this issue, and some localities try to compensate for this.
The second misunderstanding is that LOS only measures delay during the “peak-of-the-peak” (usually just the busiest 15 minutes of the day). Many people will see a bad grade and not understand that it only applies to a small portion of the day.
But the really big misunderstanding is that LOS “A” is not the best grade. LOS “A” means the road is overbuilt. In other words, taxpayers wasted money on the roadway. The best grade is actually around “C”. Intersections with LOS “C” still perform pretty darn well during peak hours, and very well the rest of the day.