Test di esercitazione CDL General Knowledge
Le domande del test restano in inglese.
Questo è un assaggio gratuito da 15 domande sul test CDL general knowledge, scritto dal team di StudyPDF. Copre l'ispezione pre-viaggio, le retromarce e le svolte, la gestione dello spazio e della velocità, il riconoscimento dei pericoli, il controllo delle sbandate, l'ancoraggio del carico, gli incendi e le regole sull'alcol, alternando domande a scelta multipla, a risposta multipla e completamento di frasi. Air brakes, combination vehicles e hazardous materials sono test separati, quindi qui non ci sono. Rispondi a tutte e 15 le domande, poi guarda il punteggio e leggi la spiegazione di ognuna.
Federal rules require a commercial vehicle to carry a set of emergency equipment. Which set is correct?
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1. Federal rules require a commercial vehicle to carry a set of emergency equipment. Which set is correct?
- A. A first aid kit, a tire pressure gauge and a flashlight
- B. Two red flags, jumper cables and a spare fuel filter
- C. Three red reflective warning triangles, at least one charged and rated fire extinguisher, and spare electrical fuses if the vehicle uses them
- D. A wheel chock, a reflective vest and a spare drive belt
Mostra risposta e spiegazione
Risposta: C. Three red reflective warning triangles, at least one charged and rated fire extinguisher, and spare electrical fuses if the vehicle uses them
You check this equipment during the in-cab step of the seven step inspection, before you check the lights and start the walkaround. Warning devices mark your vehicle for other drivers when you have to stop on the shoulder, the extinguisher has to be charged and rated for what you haul, and fuses only apply if the vehicle uses them, since many use circuit breakers instead. A first aid kit and a flashlight are smart to carry, but they are not what the rule asks for.
2. You are on the walkaround part of your pre-trip inspection. Which findings mean the vehicle should not go out until it is repaired?
Seleziona tutte le risposte corrette.
- A. A steering axle tire measuring 3/32 inch of tread
- B. A recapped tire on a drive axle
- C. A cut in a tire deep enough to show the body ply underneath
- D. A rear tire measuring 5/32 inch of tread
- E. A crack running across the rim of a wheel
Mostra risposta e spiegazione
Risposta: A. A steering axle tire measuring 3/32 inch of tread, C. A cut in a tire deep enough to show the body ply underneath, E. A crack running across the rim of a wheel
Front tires carry the steering and the most load per tire, so they need more tread than the rest, and 3/32 inch is under the minimum. Any tire with fabric, body ply or belt material showing is unsafe no matter how much tread is left, and a cracked or bent rim can let a tire come off the wheel. A recapped tire is legal on a drive axle, and 5/32 inch on a rear tire is above the minimum, so neither of those grounds the vehicle.
3. Complete the sentence.
Federal rules set a minimum tread depth of _____ inch on the tires of the steering axle and _____ inch on every other tire.
Opzioni per lo spazio 1: 2/32, 4/32, 6/32, 8/32
Opzioni per lo spazio 2: 1/32, 2/32, 4/32
Mostra risposta e spiegazione
Risposta: 4/32, 2/32
Measure in a major groove, not on a rib or a wear bar, and check more than one spot, since uneven wear can leave one shoulder legal and the other bald. Tread depth is one of the few numbers the general knowledge test asks you for directly. Uneven wear is also a clue to something else, so a front tire wearing on one edge usually means an alignment or inflation problem rather than a tire problem.
4. You have to back into a space and you can choose which side to back toward. What is the safer choice and why?
- A. Back toward the driver side, because you can see that side of the vehicle directly as well as in the mirror
- B. Back toward the passenger side, because that mirror is convex and shows a wider view
- C. Either side is equally safe as long as you use both mirrors
- D. Back toward the passenger side, because oncoming traffic sees you sooner
Mostra risposta e spiegazione
Risposta: A. Back toward the driver side, because you can see that side of the vehicle directly as well as in the mirror
Backing toward the passenger side is blind side backing, and it forces you to trust one mirror for a whole quarter of the vehicle. A wider mirror view does not make up for losing the direct look. Whichever side you use, get out and walk the area first, back slowly, and if you have a helper, agree on hand signals in advance and keep the helper somewhere you can see in the mirror, with a clear signal that means stop.
5. You are making a tight right turn at an intersection in a long vehicle. What is the correct technique?
- A. Swing wide to the left first so the rear has room, then complete the turn
- B. Move to the center of the road before the turn so nobody can come up on your right
- C. Turn from the left lane whenever the corner looks tight
- D. Keep the rear of the vehicle close to the curb and swing wide only as you complete the turn
Mostra risposta e spiegazione
Risposta: D. Keep the rear of the vehicle close to the curb and swing wide only as you complete the turn
The rear wheels follow a tighter path than the front wheels, which is called off tracking, so a long vehicle has to turn wide somewhere. Doing it at the end keeps the gap on your right closed. If you swing left first, a driver behind you may read it as a left turn or slip into the space on your right and get squeezed against the curb. If you cannot make the turn without crossing into the oncoming lane, wait until that lane is clear rather than starting the turn and hoping.
6. Complete the sentence.
Below 40 mph, allow one second of following distance for every _____ feet of vehicle length. At 55 mph, a 60 foot combination should therefore keep at least _____ seconds of space ahead.
Opzioni per lo spazio 1: 5, 10, 15, 20
Opzioni per lo spazio 2: 4, 5, 6, 7
Mostra risposta e spiegazione
Risposta: 10, 7
Sixty feet divided by ten gives six seconds, and above 40 mph you add one more second, which makes seven. To count it, watch the vehicle ahead pass a fixed object such as a sign or an overpass shadow, then count the seconds until the front of your vehicle reaches the same point. Add more space on wet or icy roads, at night, and any time you are following something you cannot see past.
7. Total stopping distance is the sum of which three distances?
- A. Perception distance, braking distance and skid distance
- B. Perception distance, reaction distance and braking distance
- C. Reaction distance, braking distance and following distance
- D. Sight distance, reaction distance and braking distance
Mostra risposta e spiegazione
Risposta: B. Perception distance, reaction distance and braking distance
Perception distance is how far you travel from the moment your eyes see a hazard until your brain recognizes it. Reaction distance is how far you travel from that recognition until your foot reaches the brake. Braking distance is how far the vehicle travels once the brakes are actually working. The model manual puts all three together at 55 mph on dry pavement with good brakes at roughly 335 feet, which is longer than a football field, and that is why looking far ahead buys you more than any braking technique.
8. Which statements about speed and stopping are true?
Seleziona tutte le risposte corrette.
- A. Braking distance grows in step with speed, so twice the speed means twice the distance
- B. Doubling your speed roughly quadruples the braking distance
- C. An empty truck can need a longer stopping distance than a loaded one
- D. Wet pavement makes no difference as long as the tires have legal tread
- E. Posted curve speeds are set with cars in mind, so a heavy vehicle often has to go slower than the sign
Mostra risposta e spiegazione
Risposta: B. Doubling your speed roughly quadruples the braking distance, C. An empty truck can need a longer stopping distance than a loaded one, E. Posted curve speeds are set with cars in mind, so a heavy vehicle often has to go slower than the sign
Braking distance grows with the square of speed, so the jump from 20 to 40 mph costs you about four times the distance, not two. An empty truck feels nimble but has less weight pressing its tires down, and its brakes and suspension are built for a load, so it can skid and stop poorly. On wet roads the usual guidance is to cut your speed by about a third, on packed snow by about half, and on ice to slow to a crawl and get off the road as soon as you safely can.
9. How far ahead should you be looking while you drive?
- A. About 2 to 4 seconds ahead, since that is where a hazard would actually reach you
- B. Only as far as your headlights reach, so you do not miss what is close
- C. About 12 to 15 seconds ahead, which is roughly a quarter mile at highway speed
- D. About 30 seconds ahead, which is roughly a mile at highway speed
Mostra risposta e spiegazione
Risposta: C. About 12 to 15 seconds ahead, which is roughly a quarter mile at highway speed
Twelve to fifteen seconds is about one city block in town and about a quarter mile on the highway. At that range you still have time to slow smoothly or change lanes instead of braking hard. Looking far ahead does not mean staring at one point, so keep scanning near and far and check your mirrors every five to eight seconds, more often when traffic is heavy or you are near other vehicles.
10. Why should you shift into a low gear before you start down a long, steep grade?
- A. Because engine braking then helps hold your speed, and the transmission may not let you get into a low gear once you are already rolling fast
- B. Because a low gear increases air flow through the radiator and stops the engine overheating
- C. Because the higher the gear, the harder the service brakes hold
- D. Because a low gear locks the drive axles together and gives you extra traction
Mostra risposta e spiegazione
Risposta: A. Because engine braking then helps hold your speed, and the transmission may not let you get into a low gear once you are already rolling fast
Gravity keeps adding speed the whole way down, so the gear does the steady work and the brakes are there to supplement it, not to carry the descent alone. Brakes that are held on continuously heat up and fade, and by the time you notice that they are fading you have very little left. Your safe speed depends on the weight, the length and steepness of the grade, the road surface and the weather, so read the signs at the top and know where the escape ramps are before you need one.
11. Complete the sentence.
Cargo held down with tiedowns needs at least one tiedown for every _____ feet of cargo, and no load, however short, may have fewer than _____ tiedowns.
Opzioni per lo spazio 1: 5, 8, 10, 12
Opzioni per lo spazio 2: one, two, three
Mostra risposta e spiegazione
Risposta: 10, two
The count is only half of it, since the combined working load limit of the tiedowns has to be at least half the weight of the cargo they hold. Securement is also the driver's job even when someone else loaded the trailer, so inspect the load before you leave, again within the first 50 miles, and then every 150 miles or every 3 hours, whichever comes first. Weight that sits too high raises the center of gravity and makes a rollover in a curve or an exit ramp much easier.
12. A fire starts in the wiring behind your dashboard. Which extinguisher is right, and what must you not do?
- A. A class A extinguisher, and do not aim at the base of the flames
- B. Water, and do not open the hood
- C. A class D extinguisher, and do not shut the engine off
- D. A B:C or A:B:C extinguisher, and do not put water on an electrical fire
Mostra risposta e spiegazione
Risposta: D. A B:C or A:B:C extinguisher, and do not put water on an electrical fire
Class A covers ordinary combustibles like wood, paper and cloth, class B covers burning liquids such as fuel and grease, class C covers electrical fires and class D covers burning metals. Water conducts electricity and it spreads a liquid fire instead of putting it out, so the B:C rating is what matters here. Before you use it, pull well off the road away from buildings and other vehicles, shut the engine off, call for help, then stay upwind, aim at the base of the flames and use short bursts. Only fight a fire that is small enough for you to handle.
13. You are approaching a railroad crossing with no gate and a clear view of the track. What should you do?
- A. Shift down as you reach the rails so you can accelerate away quickly
- B. Stay in one gear the whole way across, and do not start across unless you can clear the far side without stopping
- C. Stop on the near rail, look both ways, then move on
- D. Speed up so you spend less time on the tracks
Mostra risposta e spiegazione
Risposta: B. Stay in one gear the whole way across, and do not start across unless you can clear the far side without stopping
Changing gears on the crossing is how drivers end up stalled on the rails, so pick your gear before the tracks and hold it. A tractor and trailer needs roughly 14 to 15 seconds to clear a single track, longer for a double track, so you have to see room for the whole vehicle on the far side before you start. Watch for raised or humped crossings if you drive anything low slung, and remember that buses and some placarded loads have to stop at every crossing whether or not a train is coming.
14. Which statements about skids are true?
Seleziona tutte le risposte corrette.
- A. Most skids happen because the vehicle was going too fast for the conditions
- B. Black ice is easy to spot because it turns the pavement white
- C. Pressing harder on the accelerator is the quickest way to straighten out a skid
- D. In a drive wheel skid caused by braking too hard, you stop braking, let the wheels roll again, then countersteer
- E. In a front wheel skid the vehicle keeps going straight no matter which way you turn the steering wheel
Mostra risposta e spiegazione
Risposta: A. Most skids happen because the vehicle was going too fast for the conditions, D. In a drive wheel skid caused by braking too hard, you stop braking, let the wheels roll again, then countersteer, E. In a front wheel skid the vehicle keeps going straight no matter which way you turn the steering wheel
Skids are mostly a speed problem, whether that is braking too hard, turning too fast or accelerating too hard on a slick surface. A drive wheel skid ends when the wheels start rolling again, so you release the brake or ease off the accelerator first, then steer back the other way as the rear comes into line. A front wheel skid is different, because the steering tires have already lost their grip, so the only cure is to let the vehicle slow until they bite again. Black ice is a thin clear layer and the road just looks wet, so watch your mirror arms and antenna for ice as a warning.
15. Which statement about alcohol and a CDL is correct?
- A. A CDL holder is held to the same blood alcohol limit as any other driver in the state
- B. Coffee, fresh air or a cold shower will bring a blood alcohol level down faster
- C. Alcohol only affects a driver once the legal limit has been passed
- D. Driving a commercial vehicle with a blood alcohol concentration of 0.04 or higher is a violation, and any detectable alcohol puts the driver out of service
Mostra risposta e spiegazione
Risposta: D. Driving a commercial vehicle with a blood alcohol concentration of 0.04 or higher is a violation, and any detectable alcohol puts the driver out of service
The commercial limit of 0.04 is half the 0.08 that applies to ordinary drivers in most states, and detectable alcohol below 0.04 still gets you placed out of service for 24 hours. Drivers are also barred from drinking within four hours of going on duty. Judgment, reaction time and vision all get worse well before any legal limit is reached, and only time removes alcohol from the body, so nothing you drink or do speeds it up.
Cosa copre davvero il test CDL general knowledge
Il test general knowledge lo fa ogni candidato alla commercial driver license statunitense, qualunque classe di veicolo intenda guidare. È un test scritto dato dal tuo stato, ed è costruito sul manuale CDL dello stato stesso, che puoi scaricare gratis dal sito dell'agenzia statale che rilascia le patenti. La maggior parte dei manuali statali sono versioni leggermente ritoccate del modello AAMVA, quindi i contenuti sono quasi gli stessi ovunque. Il numero di domande e il punteggio minimo li fissa lo stato, non un ente nazionale. L'ottanta per cento è la soglia più comune, ma l'unico numero di cui fidarsi è quello stampato nel manuale del tuo stato o sul sito dell'agenzia statale. Devi superare questo test prima di qualsiasi test per un'abilitazione e prima di poter prenotare la prova pratica.
I contenuti vengono da alcuni capitoli di quel manuale. Guidare in sicurezza è il più grande: ispezione del veicolo, controllo di base, cambio marce, vedere e comunicare, gestione dello spazio e della velocità, individuazione dei pericoli, manovre di emergenza, controllo e recupero delle sbandate, guida notturna, invernale, con caldo forte e in montagna, passaggi a livello, procedure in caso di incidente e incendi. Il trasporto sicuro del carico aggiunge peso, bilanciamento e ancoraggio. Poi arrivano l'idoneità del conducente, le regole su alcol e droghe, e i limiti base delle hours of service per chi trasporta merci, attualmente 11 ore di guida dopo 10 ore consecutive di riposo, dentro una finestra di 14 ore. Le regole federali sulle ore di servizio vengono riviste, quindi verificale sulla norma FMCSA in vigore invece che su una vecchia dispensa.
Quello che cambia da stato a stato è tutto il contorno: la tariffa, quanti tentativi hai, quanto devi aspettare tra un tentativo e l'altro, se il test è su carta o su touchscreen, e se è disponibile un lettore. Air brakes, combination vehicles, cisterne, doubles e triples, passenger, school bus e hazardous materials sono tutti test separati con domande proprie, quindi general knowledge è il primo test scritto e non l'intero esame scritto. Dal 2022 valgono anche le regole federali sull'entry level driver training, che cambiano quando puoi sostenere la prova pratica e il test teorico hazmat. Controlla la pagina del tuo stato per l'ordine aggiornato dei passaggi.
Come usare questo assaggio
Queste 15 domande restano dentro il materiale di general knowledge e vanno più a fondo di un assaggio CDL misto. Chiedono perché una regola esiste, non solo cosa dice: perché fai retromarcia verso il lato guida, perché un camion vuoto può essere più difficile da fermare di uno carico, perché la marcia bassa la metti prima della discesa e non a metà. Quel ragionamento è ciò che ti tiene i numeri in testa il giorno dell'esame, ed è anche ciò che ti chiede la strada dopo. Le domande su freni ad aria, aggancio e placard qui mancano di proposito, perché appartengono ai loro test e alle loro pagine, collegate qui sotto. Se stai preparando più di un test scritto, fai quegli assaggi in sessioni separate invece di mescolare tutto.
Fallo tutto d'un fiato con il manuale chiuso, poi leggi la spiegazione di ogni domanda, comprese quelle che hai azzeccato. Tratta una risposta sbagliata come un capitolo da rileggere, non come un singolo dato da imparare a memoria. Se hai sbagliato la domanda sulla distanza di sicurezza e quella sullo spazio di arresto, l'argomento da riprendere è la gestione dello spazio nel suo insieme, non quei due numeri. Una breve lista di numeri vale davvero la pena impararla a memoria, perché il test li chiede in modo diretto: le due profondità minime del battistrada, la regola di un secondo ogni 10 piedi di lunghezza del veicolo per la distanza di sicurezza, le tre parti dello spazio di arresto, un ancoraggio ogni 10 piedi di carico con un minimo di due, e il livello alcolemico di 0,04. Al resto puoi arrivare ragionando.
Poi leggi il manuale vero e proprio. È gratis, lo finisci in qualche sera, e le domande vere escono da lì. Dove un numero letto altrove non coincide con il manuale del tuo stato, vince il manuale, perché il test l'ha scritto il tuo stato. Questo assaggio non può nemmeno coprire tutto ciò che può uscire. Guida notturna, controlli con il caldo, guida in montagna, guida distratta e aggressiva, dove vanno i dispositivi di segnalazione dopo esserti fermato sulla corsia di emergenza e cosa fare sul luogo di un incidente sono tutti argomenti d'esame e nessuno di essi è in queste 15 domande. Un modo rapido per trovare quelle lacune è scorrere i titoli dei capitoli e segnare ognuno che non sapresti riassumere in una frase.
Come StudyPDF crea test completi dai tuoi materiali
Quindici domande ti mostrano dove traballi. Da sole non bastano per arrivare pronto, e una banca dati generica non sa quale manuale statale stai studiando né su cosa insiste di più la tua scuola guida.
StudyPDF prende un'altra strada. Carichi il manuale CDL del tuo stato, le dispense della tua scuola guida o gli appunti che hai preso a lezione, e Bo, l'agente di studio, crea test completi da quelle pagine esatte. Ogni domanda nasce dal tuo materiale e ogni spiegazione indica da dove viene la risposta, così puoi andare dritto alla pagina quando qualcosa non ti torna. Puoi generare test nuovi quante volte vuoi, restringerli a un'area sola come l'ancoraggio del carico o la gestione dello spazio, e tenere traccia degli argomenti che continui a sbagliare.
Per iniziare non serve un documento. Se non hai niente da caricare, nomina invece un argomento, per esempio l'ispezione in sette passaggi o il recupero da una sbandata, e Bo ci scrive sopra un test. Inizi gratis.
Scritto dal team di StudyPDF. Ultimo aggiornamento 2026-08-19.