Glossary
Plain-English definitions of the traffic control, MUTCD, and work zone terms used across this reference.
- MUTCD
- Manual on Uniform Traffic Control Devices — the national standard for traffic signs, signals, and markings. California adopts it with state modifications as the CA MUTCD.
- CA MUTCD
- California's adoption of the federal MUTCD with state-specific modifications; governs traffic control devices on California streets and highways.
- TTC
- Temporary Traffic Control — signs, devices, and procedures that move road users safely through or around a work zone.
- TCP
- Traffic Control Plan — the drawing that shows how traffic is handled around a work area, including sign callouts, spacing, and devices.
- TPAR
- Temporary Pedestrian Access Route — the accessible pedestrian path that must be maintained when a sidewalk or crosswalk is affected by work.
- Advance Warning Area
- The section of a TTC zone where drivers are first told what to expect ahead, typically opened by W20-series signs.
- Taper
- A line of channelizing devices that moves traffic out of its normal path, e.g. for a lane closure.
- Encroachment Permit
- Agency permission required to perform work within the public right-of-way.
- Retroreflectivity
- A sign sheeting property that returns vehicle headlight light back to the driver, keeping signs legible at night.
- Object Marker (OM)
- A striped retroreflective panel that marks fixed objects or obstructions in or near the roadway.
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