Blue corridors come from OpenStreetMap lane tags (September 2026): named trunk to tertiary roads with three or more through lanes in a direction. Turn-only lanes are left out where OSM marks them; bus lanes count. Where a bus lane, busway, peak-only lane or not-yet-built lane runs along a corridor, its blue is hidden under it, so the two never share a stretch of road. Where tagging is patchy, short untagged gaps between qualifying stretches are inferred, and drawn fainter.

Each line is one connected street, counted once where it is divided. Its lane figure is the typical count along it, and its length is centreline length. About 1,050 km in all.

Bus lanes are LADOT/Metro as-built striping, cross-checked against Streetsblog LA's bus lane tally (Aug 2024), plus hand-verified additions (Florence Av, Culver City, Long Beach's 1st St transit mall) and Lincoln Bl from a regional inventory. South Bay, Pasadena and most of East LA were checked and have none installed — blank there is a verified absence, not missing data. Wilshire's eastbound lane at the VA (Bonsall to San Vicente) is not drawn: it is out of service while the D Line's VA station is built (opening fall 2027).

Busways / BRT: the G Line (including a section closed for construction) and the J Line — solid on the El Monte Busway and Harbor Transitway, whose ExpressLanes are shared with carpools and toll traffic; dashed where it runs in general traffic.

Green dashed lines are bus lanes not yet built, from Metro's Speed & Reliability map with statuses re-checked in Sept 2026: under construction or planned. Vermont's quick-build lanes and its BRT are one project now, all planned. Untick them under Layers to hide them.

Peak-only 3rd lanes are hand-curated from LADOT's parking-restriction roster; LA publishes no per-sign dataset.