Construction Zone Traffic Control (C-31) · Lesson 6 of 6

Cone, Drum and Channelizing Device Specifications

"Cone, Drum and Channelizing Device Specifications" is lesson 6 of 6 in the Construction Zone Traffic Control (C-31) Learning Hub. It opens with "Pick the Device for the Job" and works through 5 short steps, then a worked example you can check yourself against.

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Steps in this lesson

  1. Pick the Device for the Job
  2. Cone Height and Conditions
  3. Where the Retroreflective Bands Go
  4. Drums, Tubular Markers and Barricades
  5. Keep Them Working

The worked example in the course applies this lesson to a realistic job in 5 steps, from "Height check" through "Drum check".

What you'll be able to do

  • Explain the main idea of "Cone, Drum and Channelizing Device Specifications" in plain language you can use on the exam.
  • Apply this step with confidence: "Where the Retroreflective Bands Go".
  • Apply this step with confidence: "Drums, Tubular Markers and Barricades".
  • Apply this step with confidence: "Keep Them Working".
  • Test yourself on the worked example and the quick-check quiz inside the classroom.
Channelizing Device Specifications28-IN CONE, SIDE VIEW28 in min4 in from top6 in white band2 in gap4 in bandtop band bottom: 18 inlower band: 12-16 inbands measured up from the baseNIGHT FREEWAY DEVICE CHECKCONES (6K.03, 12-3.02B)Height 28 in min (freeway or night)Top band 6 in, 4 in from top: 18-24 inLower band 4 in, 2 in below: 12-16 inVisible at 1,000 ft (high beams)DRUMS (6K.06)36 in high min, 18 in wide minStripes 4-6 in: 2 orange + 2 whiteTop stripe orange; closed topNo metal drums; no ballast on topNever mix device types on one alignment(Std. Specs 12-3.01A(1))28-in night cone: bands at 18-24 in and 12-16 in above the baseBands visible at 1,000 ft under legal high-beam headlightsDrums: 36 x 18 in minimum, never mixed with cones on one alignmentSource: CA MUTCD 2026 Sections 6K.03, 6K.06; 2025 Caltrans Std. Specs 12-3.01A, 12-3.01B, 12-3.02BCC
The diagram for this lesson, exactly as it appears in the Learning Hub.

The first steps of this lesson

Step 1: Pick the Device for the Job

CA MUTCD 2026 Section 6K.01 lists the channelizing devices: cones, tubular markers, channelizers, portable delineators, vertical panels, drums, barricades and longitudinal channelizing devices. Cones suit short-duration work and tapers; drums are highly visible and generally used where they will stay in place a long time (Section 6K.06); tubular markers and portable delineators have less visible area and are for tight spaces where bigger devices will not fit (Section 6K.04). Section 12-3.01A(1) of the 2025 Caltrans Standard Specifications also says not to use different types of channelizing devices on the same alignment.

Step 2: Cone Height and Conditions

Section 6K.03 says cones must be predominantly orange and made of a material that can be struck without damaging the vehicle. For daytime and low-speed roadways they must be at least 18 inches tall. On freeways and other high-speed highways, at night on all highways, or when more conspicuous guidance is needed, cones must be at least 28 inches tall. The Caltrans Standard Specifications 12-3.02B make it simple for contract work: overall height at least 28 inches, bottom inside diameter at least 10.5 inches, flexible orange, and a retroreflective cone sleeve at night. Anchor the base if the cone is not heavy enough to stay upright (12-3.02C).

The remaining 3 steps, the worked example and the quiz are in the course. This is a preview. The full lesson, with the step-by-step explanations, a worked example and a quick-check quiz, is inside the classroom.

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