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Free Practice Questions for Iowa CDL School Bus

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Exam Review

Key Facts: Iowa CDL School Bus Exam

20 questions

Iowa School bus knowledge test length (up to 4 may be missed)

Iowa DOT CDL Testing

300-500 ft

Amber lamp distance before a stop where the limit is 45 mph or more

Iowa Code section 321.372

150 ft

Minimum amber lamp distance where the limit is under 45 mph

Iowa Code section 321.372

15 ft

Closest an overtaking driver may stop behind a stopped school bus

Iowa Code section 321.372

Twice a year

Minimum evacuation drills and safe-riding instruction for transported pupils

281 IAC 43.26

$10

Iowa School Bus endorsement fee

Iowa DOT Driver's License Fees

Iowa's School bus knowledge test has 20 questions, and you may miss up to 4. It covers Section 10 of the Iowa CDL Manual (danger zones, mirrors, loading and unloading, evacuation, railroad crossings, student management, and ABS) plus Iowa rules such as amber lamps 300 to 500 feet before a stop where the limit is 45 mph or more.

Sample Iowa CDL School Bus Practice Questions

Try these sample questions to review concepts for the Iowa CDL School Bus exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 185+ question experience with AI tutoring.

1Which endorsements does Iowa require on a CDL to drive a school bus that carries students?
A.School Bus (S) only
B.Both Passenger (P) and School Bus (S)
C.Passenger (P) only, if the bus seats 16 or more
D.School Bus (S) plus Tank (N)
Explanation: Iowa DOT says the Passenger endorsement alone is not valid for school buses; school bus operation requires both the passenger and school bus endorsements. Iowa Code section 321.376 likewise requires a school bus driver to hold a CDL with a passenger endorsement and a school bus endorsement.
2A mechanic drives an empty school bus from the bus barn to a repair shop. What does Iowa Code section 321.376 require of the mechanic?
A.A school bus driver's authorization and an S endorsement
B.Only a noncommercial license, because no students are aboard
C.An S endorsement but no P endorsement
D.A CDL for that vehicle with a P endorsement, but not the S endorsement
Explanation: Section 321.376 says a mechanic, delivery driver, or other person operating an empty school bus for purposes other than transporting passengers is not a school bus driver for this purpose. Such a person must still hold a CDL valid for the vehicle's size and type, including a passenger endorsement, but does not need the school bus endorsement.
3How many questions are on Iowa DOT's School Bus knowledge test, and how many may you miss?
A.20 questions, up to 4 missed
B.25 questions, up to 5 missed
C.30 questions, up to 6 missed
D.50 questions, up to 10 missed
Explanation: Iowa DOT lists the School bus knowledge test as 20 questions with 4 allowed misses, which is the 80% passing standard. You also need the Passenger test (20 questions, 4 misses) and the general knowledge test.
4Before Iowa DOT gives the school bus skills test to a first-time S applicant, what must be on record?
A.A first-aid and CPR card
B.A district defensive-driving course completed within the last 30 days
C.Entry-level driver training (ELDT) for the school bus endorsement
D.Nothing beyond the passed knowledge tests
Explanation: Under the federal ELDT rule, Iowa DOT must verify that applicants have completed entry-level driver training before giving the skills test for a Passenger or School Bus endorsement. Iowa DOT's endorsement page lists school bus endorsement ELDT among the steps.
5Under Iowa's pupil transportation rule 281 IAC 43.11, by when must a school bus driver be at least 18 years old?
A.By the first day the student route runs that fall
B.By January 1 of the school year
C.On or before August 1 before that school year
D.By the date the CDL is issued
Explanation: Rule 281 IAC 43.11 says school bus drivers must be at least 18 years of age on or before August 1 preceding the opening of the school year for which an authorization is required. Iowa Code section 321.375 also sets 18 as the minimum age.
6Under 281 IAC 43.13, how often is an Iowa school bus driver's authorization issued, and what must the driver do with it?
A.Annually, and a copy is carried whenever the person is driving
B.Every eight years, along with the CDL renewal
C.Once at hiring, and it stays on file at the school district office
D.Every two years, and it is posted inside the bus
Explanation: The local board of education or its designee issues a school bus driver's authorization for each approved driver annually once the Iowa Code section 321.375 requirements are met. Every school bus driver must carry a copy of the authorization when acting as a driver.
7Under 281 IAC 43.12, what physical-exam schedule applies to an Iowa school bus driver who is not insulin-dependent?
A.An exam every year by any licensed nurse
B.An exam only when the CDL is renewed
C.A single exam at hiring, with no later exams
D.A biennial exam by a National Registry examiner, with the certificate submitted annually
Explanation: Except for insulin-dependent diabetics, an applicant for a school bus driver's authorization undergoes a biennial physical exam by a certified medical examiner on the National Registry and submits the signed medical examiner's certificate to the employer annually. Insulin-dependent diabetics are subject to an annual exam.
8Which of these is listed in Iowa Code section 321.375 as grounds for immediate suspension of a school bus driver from duties?
A.Any speeding ticket received in a personal car
B.Use of alcoholic beverages during working hours
C.Declining to drive an extracurricular activity trip
D.Being late to a route after a mechanical breakdown
Explanation: Section 321.375(3) lists grounds for immediate suspension pending a termination hearing, including use of nonprescription controlled substances or alcoholic beverages during working hours and operating a school bus under their influence. Other grounds include fraud in getting the authorization and listing on certain abuse or sex offender registries.
9A driver holds a temporary restricted license issued under Iowa's OWI chapter (321J). May the driver operate a school bus?
A.No; Iowa Code section 321.376 bars that license from school bus use
B.Yes, if the restriction allows driving to and from the person's work
C.Yes, if an ignition interlock is installed on the bus
D.Yes, with written approval from the school principal
Explanation: Iowa Code section 321.376(1)(c) says a person holding a temporary restricted license issued under chapter 321J shall not operate a school bus. No work-route or interlock condition changes that.
10Since January 1, 2026, if an Iowa school district requires an approved course of instruction for its bus drivers, when must a driver complete it under Iowa Code section 321.376?
A.Every year before the first day of school
B.Once, before the first route, with no refresher
C.Within 30 days of hire, then every five years
D.Before or within six months of hire, then at least every 24 months
Explanation: As amended effective January 1, 2026, section 321.376 lets a school district require an approved course of instruction. If it does, the driver must complete the course before or within the first six months of employment and at least every twenty-four months after that.

About the Iowa CDL School Bus Exam

Iowa requires both the Passenger (P) and School Bus (S) endorsements to drive a school bus. The S knowledge test covers Section 10 of the Iowa CDL Manual, and Iowa law adds its own rules, such as the Iowa Code 321.372 amber-lamp distances and the 281 IAC 43.23 crossing stop for every school bus. This independent multiple-choice practice by OpenExamPrep helps you study those topics; it is a study aid, not a copy of the official test, and it does not replace the skills test.

Exam sponsor: Iowa Department of Transportation. The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Assessment

The School bus knowledge test covers Section 10 of the Iowa CDL Manual and is taken with the Passenger and general knowledge tests. After holding a CLP at least 14 days and completing school bus ELDT, applicants take a pre-trip inspection, skills backing, and on-road driving test in a school bus of the class they want. Separately, Iowa school bus drivers need an annual school bus driver's authorization under 281 IAC 43.

Time Limit

Iowa DOT does not publish a time limit for the School bus knowledge test

Passing Score

80% (20 questions; up to 4 missed)

Exam / Certification Fees

$10 School Bus endorsement plus $10 Passenger endorsement; $12 CLP; CDL $8 per year of the term; $10 card fee if added outside the renewal period (Iowa DOT)

Exam sponsor website

Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.

Our practice resources: topics covered

We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.

Iowa DOT, Iowa Code 321.375-321.376 & 281 IAC 43

Iowa S Endorsement and Driver Rules

P and S endorsements, the 20-question/4-miss test, ELDT, driver age, authorization, physicals, suspension grounds, district training, fueling rules, evacuation drills, and post-trip checks.

Iowa CDL Manual Section 10.1

Danger Zones and Mirrors

Danger zone distances, blind spots, and adjustment of flat, convex, crossover, and inside rearview mirrors.

Iowa CDL Manual Section 10.2 & Iowa Code 321.372

Loading and Unloading

Iowa's amber-lamp distances, red lamps and stop arm, sight distance, four-lane highways, motorist duties, stopping position, counting students, crossing procedures, and post-trip inspection.

Iowa CDL Manual Section 10.3

Emergency Exit and Evacuation

When to evacuate, mandatory evacuations, student assistants, safe places, hazardous spills, tornadoes, securing the bus, and injured students.

Iowa CDL Manual Section 10.4, Iowa Code 321.343 & 281 IAC 43.23

Railroad Crossings

Iowa's stop-every-time rule for school buses, opening the entrance door, hazard lights, multiple tracks, gates, passive crossings, containment space, and stalled buses.

Iowa CDL Manual Sections 10.5 to 10.7

Student Management and Special Safety

Handling behavior problems, ABS requirements and use, strobe lights, high winds, backing, and tail swing.

Preparing for the Iowa CDL School Bus Exam

What You Need to Know

  • Passing score: 80% (20 questions; up to 4 missed)
  • Assessment: The School bus knowledge test covers Section 10 of the Iowa CDL Manual and is taken with the Passenger and general knowledge tests. After holding a CLP at least 14 days and completing school bus ELDT, applicants take a pre-trip inspection, skills backing, and on-road driving test in a school bus of the class they want. Separately, Iowa school bus drivers need an annual school bus driver's authorization under 281 IAC 43.
  • Time limit: Iowa DOT does not publish a time limit for the School bus knowledge test
  • Exam / certification fees: $10 School Bus endorsement plus $10 Passenger endorsement; $12 CLP; CDL $8 per year of the term; $10 card fee if added outside the renewal period (Iowa DOT) Official sources

Using Our Practice Resources

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Iowa CDL School Bus: Suggested Study Strategy

1Study Section 10 of the Iowa CDL Manual, then the Iowa rules in Iowa Code sections 321.372 and 321.343 and 281 IAC 43.
2Memorize the Iowa amber-lamp distances: 300 to 500 feet at 45 mph or more, at least 150 feet under 45 mph.
3Know each mirror's view: flat mirrors 200 feet behind, convex mirrors the sides and a lane on each side, crossover mirrors the front bumper area to the service door.
4Learn the evacuation rules: when evacuation is mandatory, where the safe place is, and how to secure the bus first.
5Practice the crossing steps: hazard lights about 200 feet before, stop 15 to 50 feet from the nearest rail, open the entrance door and window, and never shift gears on the tracks.

Frequently Asked Questions

Which endorsements do I need to drive a school bus in Iowa?

Both the Passenger (P) and School Bus (S) endorsements. Iowa DOT notes that the Passenger endorsement alone is not valid for school buses, and Iowa Code section 321.376 requires a CDL with both.

When must Iowa school bus drivers turn on the amber lamps?

Under Iowa Code section 321.372, not less than 300 feet nor more than 500 feet before the stop where the speed limit is 45 mph or more, and not less than 150 feet before the stop where it is under 45 mph. At the stop, the driver turns off the amber lamps, turns on the red lamps, and extends the stop arm.

Does an empty Iowa school bus have to stop at railroad crossings?

Yes. Rule 281 IAC 43.23 says school bus drivers must follow Iowa Code section 321.343 whether or not pupils are aboard and whether or not the crossing has an automatic signal. After stopping 15 to 50 feet from the nearest rail, the driver opens the entrance door, looks and listens, and crosses only when it is safe.

How many questions are on the Iowa School bus knowledge test?

Iowa DOT lists it as 20 questions, and you may miss up to 4. You must also pass the Passenger and general knowledge tests.

What else does Iowa require of school bus drivers besides the CDL?

Drivers need an annual school bus driver's authorization from the local school board, a biennial physical by a National Registry examiner with the certificate submitted each year, and must be at least 18 by August 1 before the school year. If the district requires an approved course, it must be completed within six months of hire and at least every 24 months.