School Bus Endorsement (S): Requirements and Test Topics

What the S endorsement requires under federal rules

Federal rules set three requirements for S (49 CFR 383.123(a)), and the training and permit rules add two more:

For federal purposes, a school bus is a CMV used to carry pre-primary, primary, or secondary students between home and school or to and from school-sponsored events. It does not include for-hire motor carrier operations (383.5).

Because the S skills test must be taken in a school bus of the group you will drive, testing in a smaller bus limits you. S also requires P, and the bus you use for the P skills test can bring the M restriction (no Class A passenger vehicle) or the N restriction (no Class A or B passenger vehicle) under 383.95(e) and (f). Drivers who held S before February 7, 2022, do not need the school bus training for that endorsement (380.603(b)). The steps you take for P first are in the passenger endorsement guide.

What the S knowledge test covers

Federal rules name four topic areas (383.123(a)(2)):

1. Loading and unloading children, including safe use of stop signal devices, outside mirror systems, flashing lights, and the other warning and safety devices that state or federal rules require on school buses.
2. Emergency exits and evacuation of passengers.
3. State and federal laws on railroad crossings.
4. Other operating practices.

State school bus chapters, which follow the AAMVA model, fill in the detail. Washington's guide covers these points, among others:

• Danger zones. The danger zone around the bus may extend up to 30 feet in front of the bumper, with the first 10 feet the most dangerous, plus 10 feet on each side and 10 feet behind. The left side is always dangerous because of passing cars.
• Mirrors. Flat, convex, crossover, and overhead inside mirrors each cover a different area, and you must know what each one should show when it is adjusted correctly.
• Special dangers at stops. Students who drop something near the bus should leave it, move out of the danger zone, and get your attention. Clothing or bags can catch on the handrail or door as a student steps off.
• Evacuation. The guide lists situations that require evacuation, such as a fire or threat of fire, or a bus stalled on or next to railroad tracks, and others where keeping students aboard may be safer.
• Railroad crossings. In general, school buses stop at all crossings, but the exact procedure is set by each state.
• Tail swing. A school bus can swing its rear up to three feet outward in a turn, so you watch your mirrors before and during turns.

The number of questions is a state choice. As checked on October 28, 2026, Washington's school bus test has 20 questions with 16 needed to pass. Full CDL prep planned for launch includes 206 School Bus questions, and the federal topics above read the same for 2027 test dates.

A loading stop: when may the bus move?

This scenario is original, and the driver is fictional. On an afternoon route, Jamal lets seven students off at a stop. In his mirrors he can see six of them on the sidewalk, well clear of the bus. The seventh is out of sight. Traffic behind him is waiting, and the next stop is close.

• The tempting answer: assume the seventh student crossed behind a parked car, and pull away so traffic can move.
• The answer the manuals teach: the bus does not move until every student who got off is accounted for. Washington's guide tells drivers to count students as they unload, and if one is missing outside the bus, to secure the bus and check around and underneath it.

The federal training curriculum makes the same point from the other side: drivers must learn procedures that confirm the danger zone is clear and that no student is caught in the door before the bus moves (49 CFR Part 380, Appendix D). The exact sequence of lights, stop arm, parking brake, and door is set by your state's law and your district's procedures, which is why this guide does not script it. Full CDL prep planned for launch explains why each School Bus answer is right or wrong, but on the route, your district's procedure is the one to follow.

What your state and district add to the S endorsement

Washington's guide opens its school bus chapter with a warning: state and local laws regulate so much of school transportation that many procedures differ from state to state. Two Washington examples show how far that goes:

• Its guide says you need a CDL for all school buses regardless of size, which is broader than the federal 16-passenger line.
• Its skills test requires the school bus to meet the specifications set by the state's Office of Superintendent of Public Instruction.

The federal curriculum also requires training providers to teach state and local procedures for railroad crossings and school bus inspections. Before you plan your training, ask your state licensing agency and the district or contractor you will drive for:

• Whether the state requires its own school bus driver certificate, training hours, or background check beyond the CDL.
• Which railroad crossing, loading, and unloading procedures the state and district use.
• What equipment the test bus must have.

ELDT for the school bus endorsement

The federal school bus curriculum (49 CFR Part 380, Appendix D) has no minimum hours, but every topic must be covered, and you need at least 80% overall on the theory assessment (380.715). Its theory units include danger zones and mirror use under the federal mirror standard for school buses, loading and unloading, post-crash procedures, evacuation, railroad crossings, student management, strobe lights, high winds, backing, tail swing, inspections of stop arms and crossing arms, security, and route reviews. The behind-the-wheel part takes place in a school bus of the same group you will drive, and it includes checking the bus for sleeping children and lost items at the end of the route.

If you are new to P as well, you also complete the passenger curriculum. The ELDT guide explains how the registry works, and the CDL endorsements overview compares S with the other codes. Passy's free CDL practice questions do not include school bus endorsement items, so for quick review once you have read your state's chapter, look at the 70 School Bus flashcards planned for launch.