Idaho Road Signs Practice Test.
Free practice exam — 55 verified questions, instant feedback.

Answer: A
A driver entering a roadway from a driveway, alley, or parking lot must yield the right-of-way to vehicles and pedestrians already traveling on the roadway, since the entering driver is the one joining established traffic flow. This rule applies regardless of which direction the entering driver intends to turn.

Answer: B
A complete stop at a stop sign must be made at the marked stop line if one is present, or before the crosswalk, or before entering the intersection if neither is marked, because stopping past that point can put the vehicle in the path of cross traffic or pedestrians. Stopping is required regardless of whether other traffic or pedestrians are visible at that moment.

Answer: A
At an uncontrolled or all-way stop where two vehicles reach the intersection at the same instant, the driver arriving from the left must yield to the driver on the right, since simultaneous arrivals are resolved by position rather than by who stops first. Assuming that stopping alone removes any further yielding decision has caused unnecessary collisions at all-way stops.

Answer: A
When a road ends at another road without traffic control devices, drivers on the terminating road must yield to traffic continuing along the through road, because the through roadway is treated as the priority route the other driver is merging into. Assuming a turn signal alone grants priority ignores the basic rule that the ending roadway always yields.

Answer: A
On an undivided roadway, traffic in both directions must stop for a school bus displaying flashing red lights and an extended stop arm, and must remain stopped until the bus resumes motion or the driver signals it is safe to proceed, because children may still be approaching the bus from either side. Assuming it is safe once no children are immediately visible overlooks kids hidden near or under the bus.

Answer: C
A driver entering a freeway from an acceleration or merge lane must adjust speed and yield to vehicles already traveling in the lane being entered, since through traffic has priority over merging traffic. Using a turn signal communicates intent but does not create a right-of-way; the merging driver still must find or create a safe gap.

Answer: C
Traffic already circulating within a roundabout has the right-of-way over vehicles waiting to enter, so an approaching driver must yield until a safe gap opens before entering the circle. Basing the decision on lane position or signals ignores the core roundabout rule that entering traffic always yields to circulating traffic.

Answer: C
A funeral procession moving as a group with headlights and hazard lights on is generally treated as a single unit that has the right-of-way through intersections, and other drivers should not break into or cross through the line unless a police officer or traffic control specifically directs them to. Passing or cutting into the procession disrupts its cohesion and creates a collision risk at intersections.

Answer: A
When a lane is too narrow for a vehicle and bicycle to travel safely side by side, a cyclist is permitted to occupy the center of the lane, and a following driver must slow down and wait for enough space to pass with a safe cushion rather than forcing a pass in a tight space. Bicyclists lawfully using the roadway are not required to yield the entire lane simply because a motor vehicle is present.

Answer: A
Move-over laws require drivers approaching a stopped vehicle with warning lights on the shoulder, such as a disabled car or service vehicle, to change into a non-adjacent lane when it can be done safely, or to slow down significantly if changing lanes is not possible, to protect people working near the roadway. Maintaining normal speed and lane position leaves little margin for error if someone steps toward the traffic lane.

Answer: C
A driver backing a vehicle must yield to pedestrians in or approaching the intended path of travel, since a vehicle in reverse has reduced visibility and pedestrians already in motion cannot always react in time to avoid it. Assuming pedestrians are responsible for watching for a reversing car reverses the actual duty, which rests with the driver operating the vehicle.

Answer: D
On a blind curve, a driver should stay fully within the marked lane, reduce speed to allow more reaction time, and be prepared to brake, since oncoming traffic could appear at any moment and there is no way to see around the curve in advance. Moving toward the centerline to gain a better view actually increases the risk of a head-on conflict with an oncoming vehicle.

Answer: C
A driver turning left at an intersection must yield to oncoming traffic that is proceeding straight through, because the through-traveling vehicle has the right-of-way over a vehicle crossing its path to turn. This holds true even at intersections without signals, since the turning movement is what creates the conflict that needs to be resolved by yielding.

Answer: B
The eight-sided octagon shape is reserved exclusively for the stop sign under the national sign standard, which allows drivers to recognize a stop sign by its shape alone even if the sign is obscured by dirt, snow, or facing away from view. No other sign message in the standard system uses the octagon shape, making it a unique and unmistakable identifier.

Answer: C
Most warning signs use a yellow diamond shape, a combination reserved for alerting drivers to changing road conditions or unexpected hazards ahead, such as curves, merges, or narrow bridges. The consistent color and shape lets a driver recognize a warning sign at a glance well before reading its specific message.

Answer: A
Orange is reserved for temporary traffic control, marking construction, maintenance, or incident work zones so drivers can quickly distinguish temporary hazards from permanent warning or regulatory signs. Because these conditions change as work progresses, drivers should expect altered lane patterns, reduced speeds, or workers near the roadway.

Answer: A
The round advance warning sign with a black X and the letters R R on a yellow background alerts drivers that a railroad crossing lies ahead, giving time to slow down, watch for the crossbuck and any train activity, and prepare to stop if signals or gates are active. Its distinctive round shape is used only for this railroad advance warning purpose.

Answer: C
The five-sided pentagon shape is used specifically for school zone and school crossing warning signs, mirroring the general outline of a school crossing guard's sign so it stands out from the diamond shapes used for typical road hazard warnings. Drivers should reduce speed and watch closely for children near these signs, especially during arrival and dismissal times.

Answer: C
A broken yellow center line indicates that passing is allowed from that side of the roadway when there is enough clear distance to complete the pass safely, while a solid yellow line on your side of the center prohibits passing. Drivers should still confirm adequate sightlines and oncoming traffic before committing to the maneuver.

Answer: B
A regulatory sign showing a symbol with a circle and diagonal slash through it indicates a prohibited action, so a no-U-turn sign specifically bans making a U-turn at that location, typically due to limited sightlines or heavy traffic. Drivers must find another location, such as the next intersection, to safely reverse direction.

Answer: C
A Do Not Enter sign is a regulatory sign warning that the roadway ahead is closed to traffic approaching from that direction, often marking a one-way street entrance from the wrong end or a highway exit ramp. Drivers who see this sign must not proceed and should find an alternate route rather than entering against the flow of traffic.

Answer: A
Green signs are used for guide information such as exit numbers, mileage to destinations, and directional guidance, helping drivers navigate routes and anticipate upcoming decisions like which lane to be in for an exit. Unlike red or yellow signs, green guide signs do not convey a regulation or an immediate hazard warning.

Answer: D
Chevron alignment signs are placed along the outside of a curve to visually guide drivers through an unexpected or sharp change in roadway direction, especially useful at night or in poor visibility when the roadway edge itself is hard to see. Their repeated pointed shape reinforces the curve's direction well beyond what a single curve warning sign alone communicates.

Answer: A
A solid white edge line marks the boundary of the usable travel lane along the right side of the roadway, giving drivers a visual reference to stay within the lane, particularly valuable at night, in fog, or in heavy rain when the pavement edge is otherwise hard to distinguish. It does not by itself indicate a lane narrowing or a change in parking rules.

Answer: D
When a vehicle hydroplanes, its tires ride on a film of water and lose contact with the pavement, so the safest response is to gently release the accelerator and hold the steering wheel straight until the tires regain contact with the road surface. Hard braking or sharp steering inputs while hydroplaning can cause the vehicle to skid once traction suddenly returns.

Answer: C
Because a bridge or overpass has air flowing beneath it as well as above it, it loses heat faster than pavement that sits on the ground, causing ice to form on bridge decks before it appears on adjacent roadway sections even when temperatures are only near freezing. Drivers should reduce speed and avoid sudden steering or braking inputs when crossing bridges in cold conditions, even if the approach road looks clear.

Answer: D
Wet pavement reduces tire traction and increases the distance needed to stop, so drivers should increase their following distance beyond what is used in dry conditions to allow enough time and space to react and brake safely. Even light rain measurably extends stopping distance compared to a dry road, making the added following distance appropriate rather than optional.

Answer: D
Selecting a lower gear on a long downhill grade allows engine braking to help control speed, reducing how much the vehicle depends on the brakes, which can overheat and lose effectiveness if used continuously over an extended descent. Coasting in neutral removes the engine's braking effect entirely and can actually make speed harder to control on a steep grade.

Answer: A
A layer of wet leaves on pavement can create a slick surface nearly as slippery as ice, because the leaves and moisture form a film between the tires and the road that significantly reduces traction for both braking and steering. Drivers should slow down and increase following distance on leaf-covered roads just as they would in icy conditions.

Answer: B
An advisory speed plaque reflects a recommended safe speed for a curve or ramp under favorable conditions, and while it is not always enforced with the same legal weight as a posted speed limit sign, ignoring it substantially increases the risk of losing control on the curve, especially at night or in wet weather. Treating it as truck-only or purely optional overlooks that it exists because the curve's geometry challenges vehicles of all types at higher speeds.

Answer: B
Alcohol is a depressant that slows the central nervous system, which delays reaction time and impairs a driver's ability to accurately judge how fast another vehicle is approaching or how much distance remains before a hazard. Feeling unaffected is not a reliable indicator, since impairment in judgment and coordination can begin before a driver subjectively notices any effect.

Answer: D
Prescription and over-the-counter medications that carry drowsiness warnings can impair reaction time, coordination, and alertness similarly to alcohol, so a driver should avoid getting behind the wheel until they understand how the medication affects them or until its effects have passed. Legality of a medication does not mean it is safe to drive while under its influence, and caffeine does not reverse the impairing effects of sedating drugs.

Answer: A
Implied consent laws are based on the idea that operating a vehicle on public roadways constitutes agreement in advance to submit to chemical testing if lawfully suspected of impaired driving, and refusing such a test typically results in its own separate penalties, such as license suspension, independent of any impaired driving charge. This concept exists precisely because a driver's after-the-fact refusal would otherwise be a way to avoid providing evidence of impairment.

Answer: C
The only way to completely eliminate alcohol-related impairment risk while driving is to not consume alcohol before getting behind the wheel, since the rate at which the body processes alcohol varies by individual and cannot be reliably predicted by a fixed waiting period. Believing a single drink and a short wait fully removes impairment risk overlooks how differently people metabolize alcohol based on factors beyond just time elapsed.

Answer: A
The designated driver concept relies on one person deciding beforehand not to drink at all, ensuring at least one member of the group is fully unimpaired and able to drive everyone home safely. Choosing a designated driver after drinking has already started, or picking whoever had comparatively fewer drinks, does not guarantee that person is actually unimpaired.

Answer: D
Combining alcohol with sedating medications, whether prescription, over-the-counter, or illegal drugs, can multiply impairing effects on reaction time, coordination, and alertness well beyond what either substance would cause alone, creating a much higher risk of a crash. This is why medication warning labels often specifically caution against combining the drug with alcohol before driving.

Answer: B
Weaving within a lane and delayed reaction to a changing signal are behaviors commonly associated with impaired driving, and officers are trained to treat such observations as reasonable grounds to investigate further, which may lead to field sobriety testing. These behaviors do not automatically prove impairment, but they are recognized indicators that something may be affecting the driver's control or attention.

Answer: A
A flashing yellow signal is a caution indication that allows a driver to proceed through the intersection without stopping, but only after slowing down and watching carefully for cross traffic, pedestrians, or other hazards. It does not require the complete stop that a flashing red signal does, since the flashing yellow is meant to alert rather than fully halt traffic flow.

Answer: D
A steady red arrow requires a complete stop and prohibits turning in that direction until the signal changes, which differs from a standard red light where a right turn after stopping may be allowed unless otherwise posted, because a red arrow specifically restricts that particular turning movement. Assuming the same turn-on-red allowance applies to a red arrow can put a driver directly in the path of a conflicting protected movement.

Answer: A
When a traffic signal is completely dark, drivers should treat the intersection as an all-way stop, coming to a full stop and then proceeding using standard right-of-way rules for uncontrolled intersections, since there is no functioning signal to allocate priority. Assuming no restriction applies because the signal is off ignores that the intersection still requires drivers to negotiate right-of-way safely.

Answer: D
A learner's permit generally allows a new driver to practice operating a vehicle only while accompanied by a licensed, qualified adult supervisor seated in the vehicle, since the permit holder has not yet demonstrated the skills tested in a full licensing exam. Assuming another permit holder can serve as supervision defeats the purpose, since neither driver has yet proven full competency behind the wheel.

Answer: C
Graduated restrictions such as limiting unsupervised driving to daylight hours are designed to reduce a new driver's exposure to higher-risk conditions, like reduced visibility and higher rates of impaired or fatigued drivers, while they build experience under comparatively easier daytime conditions. These restrictions target risk exposure during the learning period rather than aiming to control traffic volume or reserve roads for other vehicle types.

Answer: A
A green light without an arrow gives permission to proceed but does not remove the duty to yield, so a left-turning driver must wait until oncoming vehicles and crossing pedestrians close enough to pose a danger have cleared before completing the turn. Treating the green light as an automatic go-ahead ignores that unprotected left turns still carry a yield obligation.

Answer: B
Drivers must yield to an approaching emergency vehicle by pulling as far to the right as safely possible and stopping until it has passed, giving the emergency vehicle a clear and predictable path through traffic. Stopping in the current lane can block the emergency vehicle's route and create a hazard for other traffic trying to react around you.

Answer: B
A pedestrian carrying a white cane or accompanied by a guide dog signals a visual impairment, and drivers are required to stop completely and yield until that pedestrian has safely crossed, since the pedestrian may not be able to visually confirm it is safe to proceed. Honking can startle a guide dog or disorient the pedestrian rather than making the crossing safer.

Answer: D
At an all-way stop, the general right-of-way rule is that the vehicle which comes to a complete stop first is entitled to proceed first, and the right-yields-to-left rule only breaks the tie when two or more vehicles stop at essentially the same moment. Applying the right-of-way-to-the-right rule regardless of arrival order ignores that order of arrival is the primary factor at a multi-way stop.

Answer: B
The red and white downward-pointing triangle is the standard yield sign, instructing drivers to slow to a speed reasonable for conditions and yield the right-of-way to traffic on the road being entered, stopping only if necessary to avoid a conflict. Unlike a stop sign, it does not require a complete stop when the way is already clear.

Answer: B
A single-direction pavement arrow paired with a mandatory movement sign designates that lane for the indicated turn only, meaning a driver in that lane must turn right and cannot continue straight through the intersection. Treating the arrow as optional or limited to certain vehicle types risks cutting across another lane's path or blocking traffic that expects that lane to turn.

Answer: C
Blue signs are reserved for motorist services such as fuel, food, lodging, camping, and hospitals, letting drivers plan stops along a route without needing to guess what facilities might be available near a given exit. This differs from green guide signs, which handle route and destination direction rather than services.

Answer: D
Brown signs are used to direct drivers to public recreation and scenic or cultural interest areas, such as parks, campgrounds, and historic sites, distinguishing them from the blue signs used for commercial motorist services. Recognizing the brown color quickly tells a driver the sign relates to a recreational destination rather than a safety regulation.

Answer: A
The basic speed rule requires drivers to operate at a speed that is reasonable and safe for current conditions, which can be well below the posted limit during rain, fog, or other conditions that reduce visibility and traction. The posted limit represents a maximum under ideal conditions, not a speed that is always safe to drive regardless of weather.

Answer: C
In fog, high beams reflect off the water droplets and bounce the light back toward the driver, reducing visibility rather than improving it, so low beams are the better choice because they illuminate the road closer to the vehicle without creating as much reflective glare. Driving with only parking lights or relying on hazard lights instead of headlights fails to adequately illuminate the roadway ahead.

Answer: C
Work zones typically carry reduced speed limits precisely because lanes may be narrowed, shifted, or partially closed, and workers may be close to moving traffic, so drivers need the extra reaction time reduced speed provides. Waiting until after passing the workers to slow down defeats the purpose of the reduced limit, which exists to protect people while they are still in the hazard area.

Answer: B
Extended wakefulness can degrade reaction time, attention, and decision-making to a degree comparable to alcohol impairment, which is why drowsy driving is treated as a serious safety hazard alongside impaired driving rather than simply a comfort issue. This risk applies to any driver on a long trip, not only to commercial drivers who may drive longer hours professionally.

Answer: B
A flashing red signal carries the same meaning as a stop sign, requiring a driver to come to a complete stop and then proceed only when it is safe and clear, yielding to any other traffic or pedestrians with the right-of-way. Treating a flashing red as a simple caution or yield situation ignores that a complete stop is required before moving again.