Traffic Control Glossary: Standards, Devices & Materials

A. Key Standards & Agencies

• MUTCD (Manual on Uniform Traffic Control Devices)
  The national standard published by the Federal Highway Administration (FHWA) that governs all traffic signs, signals, and road markings in the U.S. Devices must conform to MUTCD guidelines for size, color, placement, and retroreflectivity.

• FHWA (Federal Highway Administration)
  A division of the U.S. Department of Transportation (DOT) responsible for overseeing national highway programs, including MUTCD compliance.

• DOT-Approved
  Products marked as DOT-approved comply with the Department of Transportation's specifications. Approval may be required on a federal or state level depending on the project.

• MASH (Manual for Assessing Safety Hardware)
  A performance standard for crash-tested traffic control hardware such as barricades, barriers, attenuators, and sign supports. MASH supersedes the older NCHRP 350 standard.

• NCHRP 350 (National Cooperative Highway Research Program Report 350)
  An older crash-test standard for roadside safety hardware, now largely replaced by MASH.

• ANSI/ISEA 107
  Specifies performance requirements for high-visibility safety apparel (e.g., Class 1, 2, 3 vests), often worn in work zones.

---

 

B. Traffic Control Devices & Equipment

• Traffic Cone
  A portable, cone-shaped marker typically made of PVC or rubber, used to channel or redirect traffic. Common sizes: 18", 28", and 36". MUTCD-compliant cones for highway use must be at least 28" and have reflective collars.

• Channelizer / Channelizing Device
  Tall, vertical traffic control devices designed to guide vehicles and pedestrians. Includes delineator posts, vertical panels, and drums. Often MASH-tested.

• Delineator Post
  A flexible vertical post used to mark traffic lanes, hazards, or work zones. Can be surface-mounted or embedded. Often made of polyethylene or polyurethane.

• Traffic Drum / Construction Barrel
  Large, plastic barrel-shaped devices used to guide traffic through work zones. Typically orange with high-intensity reflective bands. Often ballasted with rubber bases or sand.

• Barricade (Type I, II, III)
  Portable barriers made from plastic or wood, featuring one to three horizontal reflective rails.

  • Type I: One rail – for low-speed or pedestrian areas

  • Type II: Two rails – for intermediate applications

  • Type III: Three rails – for road closures

• Traffic Sign
  Signs conveying regulatory, warning, or guidance information. Must conform to MUTCD specifications in shape, color, reflectivity, and messaging.

• Roll-Up Sign
  Portable fabric or mesh signs that collapse into a compact roll. Used for temporary traffic control. Require approved sign stands (some must be MASH-tested).

• Sign Stand
  A collapsible or fixed base used to display temporary or permanent signs. Some stands are crash-tested to MASH standards.

• Traffic Delineator / Tube
  Similar to a delineator post but thinner and more flexible. Used in permanent or semi-permanent installations (e.g., bike lanes, diverters).

• Speed Bump / Speed Hump
  Raised pavement sections designed to slow vehicle speeds.

  • Bump: Shorter and more abrupt

  • Hump: Wider and smoother, designed for mid-range speed reduction

• Traffic Curb / Parking Stop / Wheel Stop
  Fixed barriers installed at the end of parking spots to prevent vehicles from going beyond designated limits.

• Crash Attenuator
  A device designed to absorb impact energy and reduce crash severity. Can be permanent (e.g., on highways) or temporary (e.g., truck-mounted attenuators in work zones).

---

 

C. Materials & Reflective Grades

• Engineer Grade Reflective Sheeting
  A basic level of retroreflective material used on low-speed traffic signs and devices. Typically lasts 5–7 years.

• High-Intensity Prismatic (HIP)
  A mid-grade reflective sheeting offering higher visibility than engineer grade. Common on construction signs and permanent road signage. 10+ year durability.

• Diamond Grade Reflective Sheeting
  Premium-grade retroreflective sheeting offering the highest visibility, especially at long distances and nighttime. Used on critical or high-speed road signage. 10–12 year durability.

• Fluorescent Reflective Sheeting
  Enhanced visibility during the day and night. Often used in school zones, pedestrian crossings, or work zones.

• PVC (Polyvinyl Chloride)
  Common material for traffic cones and some delineators. Flexible, durable, and weather-resistant.

• Polyethylene (PE)
  Lightweight plastic used in barricades, drums, and posts. UV-stable and durable.

• Polyurethane
  Used in flexible delineator posts for its resilience and ability to return to shape after impact.

---

 

D. Traffic Control Zones & Terminology

• Temporary Traffic Control (TTC)
  A zone where normal traffic conditions are disrupted due to construction or maintenance. Devices must comply with MUTCD and may require MASH-tested equipment.

• Work Zone
  An area of roadway with construction, maintenance, or utility work. Requires specific signage, cones, barrels, and protective measures per MUTCD and state DOT.

• Advance Warning Area
  The section of a work zone that alerts drivers of upcoming changes. Begins with signs like "Road Work Ahead."

• Buffer Space
  A lateral or longitudinal area separating traffic from the work zone or channelizing devices. Used for safety clearance.

• Taper
  A series of channelizing devices arranged to redirect traffic into a new path, typically used when lanes merge.

---

 

E. Certifications & Classifications

• MASH-Tested / MASH-Compliant
  Equipment tested under MASH standards for safety performance in crashes. Required for many state DOT and federal projects.

• NCHRP 350-Compliant
  Indicates compliance with the older crash-test standard. Some states still accept NCHRP 350 devices, but MASH is preferred.

• ANSI Class 1, 2, 3
  Safety vest visibility levels:

  • Class 1: Low-risk zones (e.g., parking attendants)

  • Class 2: Moderate risk (e.g., road crews)

  • Class 3: High-speed, high-risk environments (e.g., highway workers)

---

 

F. Common Abbreviations