Key Numbers to Memorise
The distances, speeds and time limits the written test asks about, grouped by topic so you don't mix up the similar ones.
A lot of written-test mistakes come from mixing up similar numbers — "5 metres" vs "10 metres," "30 metres before" vs "3 seconds before." Here they are grouped by topic, each with the article of law behind it.
Parking & stopping
- 5 m — Within how many metres of an intersection or a road corner is stopping and parking prohibited?
Five metres (art. 44-1-2). Ten metres applies to safety islands, bus stops and railway crossings — mixing up 5 and 10 is a classic trap. - 5 m — Within how many metres before and after a pedestrian or cycle crossing is stopping and parking prohibited?
Five metres either side (art. 44-1-3). Not just before it — both sides. Different from the 30 m no-overtaking distance. - 10 m — Within how many metres before and after a safety island is stopping and parking prohibited?
Ten metres either side (art. 44-1-4). This is the longer number, unlike the 5 m for intersections and crossings. - 10 m — Within how many metres before and after a railway crossing is stopping and parking prohibited?
Ten metres either side (art. 44-1-6). The crossing itself is prohibited too. A pedestrian crossing is 5 m, so the numbers differ. - 10 m — Within how many metres of a bus stop post is stopping and parking prohibited (during service hours)?
Ten metres (art. 44-1-5). It applies only during the hours the service runs. - 5 m — Within how many metres of the edge of a roadworks area is parking prohibited?
Five metres (art. 45-1). Three metres is the figure for the entrance to a car park or garage. - 3 m — Within how many metres of the entrance to an off-road facility such as a car park or garage is parking prohibited?
Three metres (art. 45-1-1). Easily confused with the 5 m for intersections (art. 44). - 5 min — Loading and unloading becomes "parking" once it exceeds how many minutes?
Five minutes (art. 2). Letting people in or out is "stopping" regardless of time. In a no-stopping zone this distinction does not help you. - 5 m — Within how many metres of a fire hydrant is parking prohibited?
Five metres (art. 45-1). Stopping is still allowed — that is the difference from art. 44, where even stopping is banned. - 1 m — Within how many metres of a fire alarm is parking prohibited?
One metre (art. 45-1). A garage entrance is 3 m and a fire hydrant is 5 m — three different numbers. - 3.5 m — When you park, how many metres of clear road must remain to the right of your vehicle?
At least 3.5 m (art. 45-2). If you cannot leave that much, you may not park there. Loading or unloading where you can move off immediately is an exception.
Overtaking
- 30 m — Within how many metres before an intersection, railway crossing or pedestrian crossing is overtaking prohibited?
Thirty metres before (art. 30-3). A different number from the 5 m and 10 m of the no-stopping rules (art. 44).
How to drive on the road
- 30 m — How many metres before a turn or U-turn must you signal?
Thirty metres before (Enforcement Order art. 21). When turning at an intersection, measure from the near edge of that intersection. - 3 sec — How many seconds before changing lanes must you signal?
Three seconds before the act (Enforcement Order art. 21). The 30 m figure is for turning — confusing these two is a classic trap.
Speed & stopping distance
- 60 km/h — What is the statutory maximum speed for a car on an ordinary road?
60 km/h on an ordinary road. Where a sign posts a limit, follow the sign instead. - 30 km/h — What is the statutory maximum speed for a moped?
30 km/h. Even where a sign posts 40 or 50, a moped may not exceed 30. - 4× — If your speed doubles, roughly how many times longer is the braking distance?
About four times — braking distance is proportional to the square of speed. Centrifugal force and impact force scale the same way. - 2× — On a wet road, the braking distance can be roughly how many times that of a dry road?
About twice — the tyres grip less. Slow down and leave a longer gap.
Expressways
- 100 km/h — What is the statutory maximum speed for a standard car on a national expressway?
100 km/h as a rule. Some sections post 120 km/h by sign. - 50 km/h — What is the statutory MINIMUM speed on the main carriageway of a national expressway?
50 km/h. The main carriageway of a national expressway is the only place with a minimum speed. - 60 km/h — What is the statutory maximum speed on a motor-vehicle-only road?
60 km/h. The 100 km/h figure belongs to national expressways — the similar names make these easy to swap. - 80 km/h — What is the statutory maximum speed for a large goods vehicle on a national expressway?
80 km/h. It is not "100 for everything unless a sign says otherwise" — it depends on the class of vehicle. - 2 hours — On a long motorway drive, you should take a break roughly every how many hours?
About every two hours. Holding one speed on a monotonous road brings on fatigue and drowsiness. - 100 m — At 100 km/h on a motorway, roughly how many metres of following distance should you keep?
Roughly 100 m or more. Stopping distance grows with speed, so you need more room than on ordinary roads. The trick: the metres match the km/h.
Slowing & stopping
- 10 km/h — Driving slowly ("jokō") is roughly what speed or less?
Around 10 km/h or less. The law gives no figure; the point of the definition is being able to stop immediately, not merely going slowly. - 1 m — As a rule of thumb for "slow speed", within how many metres of braking must you be able to stop?
Within one metre. Slow speed is not "driving gently" but "able to stop at once", so remember it as a distance.
Driver's responsibilities
- 6 years old — A child seat is required for children under what age?
Under 6 (art. 71-3-3). Holding a child in your arms is not a substitute — no one can hold on in a collision. - 70 years old — From what age are drivers expected to display the older-driver plate?
Seventy (art. 71-5-3). This one is a best-effort duty; the novice plate, the hearing-impaired plate and the disabled-driver plate are compulsory.
Loads & towing
- 12 years old — For seating-capacity purposes, three children count as two adults below what age?
Under 12. Three count as two adults, but this is not unlimited — you still may not exceed the capacity. - 3.8 m — How many metres above the ground may a load reach?
3.8 metres from the ground; 4.1 metres on designated height routes. - 1.2× — A load may be up to how many times the width of the vehicle?
1.2 times (the standard after the May 2022 revision). The length limit is 1.1 times — a different number. - 1.1× — A load may be up to how many times the length of the vehicle?
The length of the vehicle plus a tenth, i.e. 1.1 times. Any overhang needs a red cloth by day and a red light by night. - 5 m — When towing a broken-down car with a rope, the gap between the vehicles must be within how many metres?
Within 5 metres. Too long a gap lets other vehicles or pedestrians catch on the rope. - 0.3 m² — The white cloth tied to the middle of a tow rope must be at least how many metres square?
0.3 metres square or larger. The red cloth for a daytime overhang is the same 0.3 metres square. - 0.15 m — How far may a load stick out beyond the vehicle width on each side?
Up to 0.15 m each side. It is the 1.2x width limit split between the two sides. - 0.3 m² — When a load overhangs, how many square metres must the red cloth be during the day?
At least 0.3 m2 of red cloth. At night use a red light or reflector instead. A towing rope needs a white cloth of the same 0.3 m2 — same size, different colour and situation.
Checks & maintenance
- 3 years — For a private standard passenger car, the first shaken inspection falls how many years after purchase when new?
Three years when new, then every two years. The annual statutory check-up is a separate thing. - 1 year — How often, in years, must a private standard passenger car have its periodic inspection?
Every year. It is separate from the shaken roadworthiness test (3 years when new, then every 2) — do not confuse inspection with certification. - 2 years — For a private standard passenger car, how often is the shaken test after the first one?
Every two years. Only the first one falls three years after registration. This is separate from the yearly periodic inspection.
How a vehicle behaves
- 4× — If your speed doubles, roughly how many times greater is the impact force in a crash?
About four times — impact force is proportional to the square of speed and to mass. "Only a little faster" costs more than proportionally.
Accidents & first aid
- 5 cm — In CPR chest compressions, the chest should be pressed down by about how many centimetres?
About 5 cm, at a rate of 100-120 per minute. First-aid procedure is examinable.
Bad conditions
- 50 m — Parking at night, you may omit the warning device where the car is visible from how many metres behind?
Where street lighting makes it visible from 50 m behind. Otherwise use hazard lights, parking lights or a warning triangle.
Signs & road markings
- 6 m — Where a "parking space 6 m" sign is posted, how many metres must remain clear to the right of your vehicle?
Six metres, as the sign states. It demands more room than the default 3.5 m (art. 45-2), and the number changes from sign to sign.
Licences & vehicle classes
- 7.5 t — A semi-medium vehicle has a gross vehicle weight under how many tonnes?
Under 7.5 t (max load under 4.5 t). It fills the gap between standard (under 3.5 t) and medium (under 11 t), and can be taken from age 18. - 3.5 t — A standard vehicle has a gross vehicle weight under how many tonnes?
Under 3.5 t. Semi-medium is under 7.5 t and medium under 11 t. - 1 year — The novice driver plate must be displayed for how many years after getting your licence?
One year (art. 71-5-2). Any period of suspension is not counted. After a year the duty ends. - 1 year — An international driving permit lets you drive in Japan for up to how many years as a rule?
One year as a rule. If you are staying on, you need to convert your foreign licence (gaimen kirikae). - 750 kg — Up to what gross weight of the towed vehicle may you tow without a towing licence?
750 kg. You also do not need the towing licence to pull a broken-down car on a rope. - 55 kg — When calculating gross vehicle weight, how many kilograms is each occupant counted as?
55 kg per person. Gross weight is not just the body — it adds the seating capacity and the maximum load. - 11 t — A medium-size vehicle has a gross weight below how many tonnes?
Below 11 t. Standard is under 3.5 t and semi-medium under 7.5 t — these three numbers mark the licence boundaries. - 4.5 t — A semi-medium vehicle has a maximum load below how many tonnes?
Below 4.5 t. Its gross weight limit is 7.5 t — keep the load figure and the weight figure apart.
Licence conversion
- 3 months — For a foreign licence conversion, how many months must you have stayed in the issuing country after getting the licence?
Three months in total. You prove it with passport entry and exit records. This is where many applicants are turned away.
