A covered truck is disabled on the shoulder of a straight, rural two-way road with no sight obstruction. Where do the two farther triangles go under the general federal arrangement?
Correct answer: About 100 feet ahead and 100 feet behind, in the occupied shoulder.
The general arrangement warns traffic from both directions: one device about 100 feet each way in the lane or shoulder occupied by the truck, plus a near device about 10 feet away on its traffic side toward approaching traffic.
Source: 49 CFR 392.22(b)(1)(i)-(iii); eCFR title 49 displayed current through September 10, 2026; reviewed September 14, 2026. Also Colorado CDL Manual (06/15/23), page 27. ↗
An exit ramp curves sharply just after beginning downhill. Why should a truck driver assess it before entering?
Correct answer: The downhill section can build speed before the sharp curve.
A downgrade can increase speed on the approach to a ramp curve. Plan a suitable entry speed early; waiting until the curve leaves less room to control a heavy vehicle safely.
Source: Colorado Commercial Driver License Manual (06/15/23), Section 2; 2.8 Seeing Hazards; physical PDF page 33 (printed 33); reviewed September 14, 2026. ↗
Under the federal CMV texting rule, may a driver type a routine dispatch reply while stopped at a red light with the engine running?
Correct answer: No. A temporary traffic stop still counts as driving.
49 CFR 392.80 includes temporary traffic stops in its driving definition when the motor is running. A routine work message is not the emergency-communication exception.
Source: 49 CFR 392.80(a), (c) and (d); eCFR title 49 displayed current through September 10, 2026; reviewed September 14, 2026. ↗
Which stop is outside the driving definition in the federal CMV texting rule?
Correct answer: Moving off the highway and halting where it is safe to remain.
The rule distinguishes a temporary traffic delay from moving to the side of or off the highway and halting where the vehicle can safely remain. Choose a genuinely safe location rather than stopping in a travel lane to text.
Source: 49 CFR 392.80(c); eCFR title 49 displayed current through September 10, 2026; reviewed September 14, 2026. ↗
A carrier tells a driver to answer routine texts while driving a CMV. How does the federal texting rule apply to the carrier?
Correct answer: The carrier must not allow or require texting while driving.
49 CFR 392.80 prohibits a motor carrier from allowing or requiring a driver to text while driving. Dispatch needs must be handled without directing the driver to violate that rule.
Source: 49 CFR 392.80(b); eCFR title 49 displayed current through September 10, 2026; reviewed September 14, 2026. ↗
Which communication fits the federal exception to the handheld-phone restriction while driving a CMV?
Correct answer: Necessary communication with emergency services about an emergency.
The exception is for communication necessary with law enforcement or emergency services. Routine business and personal calls do not qualify; this does not make a distracting or unsafe call a good driving choice.
Source: 49 CFR 392.82(a)-(c); eCFR title 49 displayed current through September 10, 2026; reviewed September 14, 2026. ↗
No train horn is audible as you approach a crossing. What can you safely conclude?
Correct answer: Nothing about whether a train is approaching; look and listen.
Train horns may not sound at some crossings, and cab noise can mask them. Silence is not permission to cross. Check the tracks and obey the warning devices and applicable stop rules.
Source: Colorado Commercial Driver License Manual (06/15/23), Section 2; 2.15.3 Driving Procedures; physical PDF page 43 (printed 43); reviewed September 14, 2026. ↗
Your vehicle is stuck at a crossing and everyone is safely away from the tracks. What information on the blue-and-white ENS sign helps you alert the railroad?
Correct answer: Its emergency telephone number and crossing identification number.
Call the railroad emergency number on the ENS sign, give the crossing identification number and describe the emergency. The ID pinpoints the crossing for the railroad; do not rely on a guessed location or return to the vehicle to make the call.
Source: FRA, In Case of Emergency, Use ENS Signs To Get Help; FRA page updated April 4, 2025; reviewed September 14, 2026. ↗
A driver says a heavily loaded truck can always descend a hill in the same gear it used to climb. Is that a reliable rule for modern trucks?
Correct answer: No. Engine and braking characteristics can require a lower descent gear.
The handbook warns against relying on the old same-gear rule for every truck. Select the appropriate low gear before descending, considering the vehicle and grade rather than applying a universal uphill-to-downhill shortcut.
Source: Colorado Commercial Driver License Manual (06/15/23), Section 2; 2.16.2 Select the Right Gear Before Starting Down the Grade; physical PDF page 44 (printed 44); reviewed September 14, 2026. ↗
