Japan Medium Vehicle Theory cheat sheet

Japanese license classes by GVW and capacity: semi-medium (準中型) covers GVW 3.5–7.5 t with max load 2–4.5 t; medium (中型) covers GVW 7.5–11 t with max load 4.5–6.5 t; large (大型) covers GVW over 11 t or max load over 6.5 t.

Semi-medium licenses obtained on or after 1 June 2007 carry a restriction (限定) barring driving vehicles with max load over 2 t until age 21 and 3 years of experience; the restriction is lifted by taking the restriction-lift course or passing the second-class (二種) test.

A medium vehicle under the Road Traffic Act is defined by GVW 7.5–11 t, max load 4.5–6.5 t, or passenger capacity 11–29 (excluding the driver); exceeding any one threshold moves the vehicle into the large-vehicle class.

General road speed limits: 60 km/h on ordinary roads unless posted otherwise; 100 km/h on expressways for medium/large vehicles (passenger cars are 100 km/h too, but towing and some conditions differ); always obey posted signs when lower.

Minimum following distance on ordinary roads: at least 2 seconds at 40 km/h, 3 seconds at 60 km/h; on expressways, the rule is 2 seconds at 80 km/h and 3 seconds at 100 km/h (the '2-second rule' baseline).

Parking and stopping prohibitions: within 5 m of a fire hydrant, 3 m of a railway crossing, 5 m of a bus stop sign, and at intersections and their sides are prohibited; medium vehicles must also avoid marked no-stopping zones (駐停車禁止).

Right-of-way: at uncontrolled intersections, the vehicle approaching from the left yields; at T-junctions, the through road has priority; pedestrians on crosswalks always have absolute priority.

Seat belts are mandatory for all occupants; medium vehicles with passenger capacity over 11 require the driver to confirm seat belt use by passengers, and children under 6 must use a child restraint.

Drunk driving thresholds: 0.15 mg/L breath alcohol or 0.3 g/L blood alcohol is the 'drunk' (酒気帯び) line; any detectable alcohol with impaired driving is punishable, and medium-vehicle commercial drivers face stricter standards and license revocation.

Defensive driving uses the SEE method: Search (scan ahead 12–15 seconds), Evaluate (identify hazards), Execute (act smoothly); for medium vehicles, extend the search distance to 15–20 seconds due to longer stopping distances.

Stopping distance = reaction distance + braking distance. Reaction distance (m) ≈ speed (km/h) × 0.28 for a 1-second reaction; braking distance grows with the square of speed, so doubling speed quadruples braking distance.

On expressways, maintain a gap of at least the distance traveled in 2 seconds; at 80 km/h that is about 44 m, at 100 km/h about 56 m; in rain, double the gap; in snow or ice, triple it.

Hazard prediction: look for cues such as brake lights two cars ahead, pedestrians near crosswalks, children near schools, parked cars with occupants, and cyclists wobbling; medium vehicles need earlier braking due to mass.

Speed management on curves: enter at a speed that allows stopping within the visible distance; on blind curves, reduce speed to half the posted limit and stay in lane, never cross the center line.

Use of horn: only for warning of danger; in no-horn zones (near hospitals, schools at night, residential areas 22:00–06:00) it is prohibited except to avoid imminent danger.

Night driving: use high beams on unlit roads; dip to low beams when a vehicle approaches within 150 m or when following within 150 m; reduce speed so you can stop within the illuminated distance.

Fatigue and microsleep: continuous driving over 4 hours requires a 30-minute break; commercial medium-vehicle drivers must record driving hours and observe the 'continuous driving 4 hours' rule under the improvement standard.

Medium trucks typically have a wheelbase of 4–6 m and a minimum turning radius of 6–8 m; the rear inner wheel tracks inside the front wheel path (off-tracking), so allow extra clearance on right turns.

Center of gravity rises with load height; a medium truck with a high load has a rollover threshold around 0.4–0.5 g lateral acceleration, lower than a passenger car's ~0.8 g, so corner entry speed must be reduced.

Braking: medium vehicles use air-over-hydraulic or full air brakes; air brake systems require pressure build-up before driving (typically 0.6–0.8 MPa), and a low-pressure warning means stop and check.

Engine braking (exhaust brake or retarder) should be used on long downgrades; riding the service brakes causes fade, and a fully loaded medium truck can lose braking effectiveness within a few minutes of continuous application.

Blind spots: medium trucks have large front blind zones (2–3 m ahead of the bumper) and right-side blind zones; mirror adjustment and shoulder checks are essential before lane changes.

Tire characteristics: medium vehicles use load-range tires; underinflation by 20% can reduce tire life by ~30% and increase heat, raising blowout risk; check cold pressure weekly.

Weight transfer: braking shifts load forward, reducing rear traction; acceleration shifts load rearward, reducing steering grip; smooth inputs are required to avoid jackknifing or loss of control.

A medium vehicle's longer stopping distance means the 2-second rule is a minimum; at 60 km/h a fully loaded medium truck may need 40–50 m to stop, versus ~30 m for a passenger car.

Legal size limits for medium vehicles: length ≤ 12 m, width ≤ 2.5 m, height ≤ 3.8 m (up to 4.1 m for designated containers), and GVW ≤ 20 t (25 t for designated vehicles) on public roads.

Axle load limit: 10 t per axle (20 t for a tandem axle group) on ordinary roads; exceeding axle loads damages pavement and is subject to weight enforcement (計量) at roadside stations.

Cargo must be secured so it cannot shift, fall, or leak; overhanging cargo at the rear is limited to 10% of vehicle length, and front overhang is prohibited beyond the bumper.

Load distribution: keep the center of gravity low and centered; uneven loading increases rollover risk and can overload one axle; check axle loads after loading.

Passenger capacity for medium vehicles is 11–29 excluding the driver; seat belts must be provided for all seats, and standing passengers are prohibited on expressways.

Cargo height above the load bed must not obscure the driver's view or lights; if cargo extends beyond the rear, mark it with a red flag or light at night.

Hazardous materials require placards and route restrictions; medium vehicles carrying dangerous goods must follow designated routes and carry fire extinguishers and documentation.

Weight tickets and loading records: commercial operators must keep loading records and ensure drivers are trained in securement; unsecured loads are a primary cause of expressway accidents.

Rain: reduce speed to 80% of dry-road speed; hydroplaning occurs at roughly 80 km/h with 2 mm of water; if hydroplaning, ease off the accelerator and do not brake hard.

Snow and ice: stopping distance can be 3–10 times longer; use gentle inputs, start in a higher gear, and avoid sudden braking; chains or winter tires are mandatory in designated areas.

Fog: use low beams and fog lights, not high beams (high beams reflect back); reduce speed so you can stop within the visible distance; if visibility is under 50 m, consider exiting the expressway.

Tire blowout at speed: grip the wheel firmly, do not brake hard, ease off the accelerator, and steer straight; brake gently only after the vehicle stabilizes, then pull to the shoulder.

Brake failure: pump the brakes (if hydraulic), downshift, use the engine brake and parking brake gradually, and look for an escape ramp or soft shoulder; do not turn off the engine (loss of steering assist).

Expressway emergency: pull as far right as possible, turn on hazard lights, place a warning triangle 150 m behind the vehicle (50 m on ordinary roads), and evacuate to behind the guardrail.

Night and rain combined reduce visibility; use headlights, increase following distance, and watch for pedestrians and cyclists without lights; reduce speed by 10–20 km/h below the posted limit.

Earthquake and disaster driving: pull to the left side of the road to leave the right lane open for emergency vehicles, turn off the engine, and follow evacuation instructions.

Pre-trip check (日常点検) items: brakes, tires (pressure and tread), lights, engine oil, coolant, washer fluid, battery, and mirrors; performed before each trip or daily.

Tire tread depth minimum is 1.6 mm; medium vehicles should have at least 3 mm for safety; check for uneven wear, cuts, and embedded objects.

Brake check: test pedal free play and air pressure; for air brakes, the low-pressure warning should extinguish after build-up; check slack adjusters and brake chambers.

Periodic inspection (定期点検): 3-month, 6-month, and 12-month inspections for commercial vehicles; the 12-month inspection is more comprehensive and includes brake dynamometer testing.

Shaken (車検) for medium vehicles: first inspection at 2 years for private use, then every 2 years; commercial use requires annual inspection; the certificate must be displayed.

Fluid checks: engine oil on level ground with the engine off; coolant at the reservoir mark; brake fluid should be clear and at the full line; power steering fluid checked cold.

Lights and signals: verify headlights, brake lights, turn signals, hazard lights, and clearance lamps; a failed brake light is a common cause of rear-end accidents.

Tire pressure should be checked cold; a 10% drop in pressure can increase fuel consumption and heat; use the manufacturer's placard value, not the tire sidewall maximum.

After an accident: stop immediately, turn on hazard lights, place a warning triangle, check for injuries, and call 119 for ambulance and 110 for police; failure to report is a hit-and-run offense (ひき逃げ).

Reporting obligation: the driver must report to police within 24 hours for property damage and immediately for injury or death; commercial drivers must also notify their employer.

First aid priorities: airway, breathing, circulation (ABC); do not move an injured person unless there is fire or traffic danger; control bleeding with direct pressure.

CPR: 30 chest compressions to 2 rescue breaths at 100–120 compressions per minute; use an AED as soon as available; medium vehicles should carry a first-aid kit and fire extinguisher.

Accident scene safety: set up warning devices 50 m behind on ordinary roads and 150 m on expressways; wear a reflective vest; move to a safe location behind the guardrail.

Documentation: exchange license, insurance, and contact information; photograph the scene, vehicle positions, and damage; note witnesses and weather conditions.

Insurance: compulsory automobile liability insurance (自賠責) covers bodily injury up to 30 million yen per person; voluntary insurance covers property and excess liability; commercial vehicles need higher limits.

Legal consequences: negligent driving causing injury (過失運転致傷) and causing death (過失運転致死) carry license suspension or revocation; alcohol-related accidents carry heavier penalties.

Eco-driving (エコドライブ): avoid sudden acceleration and braking, maintain steady speed, use air conditioning sparingly, and check tire pressure; can reduce fuel consumption by 10–20%.

Idling stop: turn off the engine when parked for more than 5 seconds; idling for 10 minutes wastes about 0.14 L of fuel and emits CO2.

Fuel-efficient speed: medium vehicles achieve best fuel economy around 50–60 km/h on flat roads; expressway cruising at 80 km/h is more efficient than 100 km/h.

Etiquette: yield to pedestrians, avoid splashing pedestrians with puddles, dim headlights for oncoming traffic, and do not use the horn unnecessarily.

Environmental regulations: medium vehicles must meet emission standards (e.g., 2016 or later standards for new vehicles); older vehicles may be restricted in urban areas.

Driver health: commercial drivers must undergo regular health checks; sleep apnea and hypertension are common risk factors; report medication that may cause drowsiness.

Vehicle maintenance and environment: proper tire pressure, clean air filters, and timely oil changes reduce emissions and fuel use; a poorly maintained engine can increase emissions by 20%.

Professional responsibility: commercial medium-vehicle drivers are role models; they must follow hours-of-service rules, avoid distracted driving (phone use is prohibited while driving), and report incidents promptly.