Stage 1 Course Content 7 — Safe Speed and Distance between Vehicles

• Maximum speed limit
• Speed and stopping distance
• Safe speed and distance between vehicles
• How to apply brakes
• Proceeding slowly

1. Maximum Speed Limit

1. Observing the Maximum Speed Limit

When driving a vehicle, a driver must make efforts to drive safely, observing regulated speed limits specified according to the conditions of the road and traffic and legally designated speed limits prescribed according to vehicle type.

• Regulated speed limit ··············· The maximum speed limit designated (regulated) by traffic signs and pavement markings
• Legally designated speed limit ······ The maximum speed limits prescribed by laws and regulations (60 km/h for automobiles and 30 km/h for general motorized bicycles)

2. Regulated Speed Limit

1. On roads where the maximum speed limit is designated by traffic signs or pavement markings, vehicles and streetcars must not drive exceeding that speed (the regulated speed limit).
2. On roads where the maximum speed limit designated by traffic signs or pavement markings is over 30 km/h, general motorized bicycles must not drive exceeding 30 km/h (the legally designated speed limit).

Sample maximum speed limit traffic signs and pavement markings

3. On roads where auxiliary signs designate the maximum speed limit for specific types of vehicles only, such types of vehicles must not drive exceeding that maximum speed.

Reference: Regulated speed limit ends Past this traffic sign, resume driving within the legally designated speed limit.

3. Legally Designated Speed Limit

On roads where the maximum speed limit is not designated by traffic signs or pavement markings (excluding national expressways), vehicles must not drive exceeding the maximum speed limit (legally designated speed limit) prescribed by laws and regulations for that type of vehicle.

(Refer to p. 245 for legally designated speed limits for expressways)

※ Light special equipment cannot travel at speeds exceeding 15 km/h due to structural limitations. ※ The maximum speed limit for driving emergency vehicles on emergency-related tasks is 80 km/h. ※ Some vehicles used for agricultural chemical spraying, though considered regular automobiles, cannot travel at speeds of 35 km/h or greater due to structural limitations. ※ Specified light motorized bicycles cannot travel at speeds exceeding 20 km/h due to structural limitations.

Legally designated speed limits when towing another vehicle

※ Even where traffic signs or pavement markings designate a maximum speed limit exceeding these legally designated speed limits, vehicles must drive obeying these legally designated maximum speed limits.

2. Speed and Stopping Distance

1. Reaction Distance, Braking Distance, and Stopping Distance

1. Vehicles cannot stop suddenly. Bringing a vehicle to a stop requires a certain distance (stopping distance) which is the sum of the distance traveled from when a driver notices danger and steps on the brakes until the brakes do start to engage (reaction distance), and the distance from when the brakes start to engage until the vehicle stops (braking distance).
2. Since the stopping distance becomes longer with higher speed, drivers must be constantly aware of stopping distance and drive vehicles at a speed that will allow for safe stopping in the event of danger.

2. When Stopping Distance Becomes Longer

1. The reaction distance becomes longer when a driver is tired because reaction is slower compared to when the driver is not tired, and it takes longer to make a judgment after noticing danger.
2. The braking distance becomes longer when a vehicle is traveling on a road wet due to rain, carrying a heavy load, etc. because of frictional force, etc.
3. When the road surface is wet and the tires are worn, the stopping distance may become about twice as long as that on a dry road surface with tires in good condition. On downward slopes, the stopping distance becomes longer depending on how steep it is.

Reaction distance + Braking distance = Stopping distance

• Reaction distance: The distance from when a driver notices danger and steps on the brakes until the brakes start to engage
• Braking distance: The distance from when the brakes start to engage until the vehicle stops

Stopping distance (for regular passenger automobiles)

• Reaction distance → Proportional to the speed
• Braking distance → Proportional to the speed squared

※ This graph indicates the shortest stopping distances required when a driver brakes suddenly while driving under normal conditions on a dry, paved road. The distances become longer when traveling on a slippery road, etc. ※ Stopping distances for two-wheeled vehicles vary greatly depending on the vehicle type (weight, engine displacement, etc.).

Reference: Longer reaction distance When the driver is tired, ill, or under the influence of medicines; if the driver is uncomfortable with the vehicle; the effect of the age and gender of the driver; or other conditions of the driver.

Reference: Longer braking distance The road surface conditions (asphalt paving, snow- or ice-covered surfaces, gravel, etc.), vehicle conditions (vehicle type, extent of tire wear, weight), and other physical factors.

3. Safe Speed and Distance between Vehicles

1. Speed in Response to Road Environment, etc.

A driver must travel at a safe speed taking into account road and traffic conditions, weather, visibility, etc. when driving a vehicle, even within the determined speed.

2. Maintaining a Safe Distance between Vehicles

A driver must take into account the weather, the road surface, tire conditions, the weight of the load, etc. and follow at a safe distance from the vehicle ahead to avoid rear-end collision even if it stops suddenly. Use the stopping distance as a guide to determine the safe distance between vehicles.

Be aware that it is easy for the distance from the vehicle ahead to become shorter than it seems for drivers of large automobiles, medium-sized automobiles, and semi-medium-sized automobiles. This is because their driver's seats are higher compared to those of regular automobiles, and the distance from the vehicle ahead feels longer than it actually is as the driver looks down from above.

Reference: Guide for safe distance between vehicles (on a dry, paved road)

① When traveling at 30 to 60 km/h A distance of the speedometer value minus 15 (meters), or more e.g. When traveling at 50 km/h, 50 - 15 = 35 m or more

② When traveling at a speed exceeding 60 km/h A distance of the speedometer value with the unit changed to meters, or more e.g. When traveling at 80 km/h, 80 m or more

Reference: Keeping a safe distance between vehicles in response to conditions

1. When the road surface is slippery, stopping distance becomes longer. Follow at a distance 1.5 times or more of that for a dry road on road surfaces with normal rain, and at a distance three times or more on frozen road surfaces.
2. When following a large vehicle, following at a short distance reduces visibility ahead, blocking the view of signals, oncoming vehicles, pedestrians, and other conditions. Follow at a distance that ensures sufficient visibility.
3. It is difficult to judge distance inside a tunnel, and the distance between vehicles tends to become shorter because the eyesight is drawn to the taillight of the vehicle ahead. Look at the entire tunnel as much as possible, not just at the vehicle ahead, and consciously follow at a longer distance.

4. How to Apply Brakes

1. How to Apply Brakes in a Four-Wheeled Vehicle

1. Step as lightly as possible to begin, and gradually apply more pressure as needed.
2. Pump the brake pedal several times (cadence braking). This method is especially effective when the road condition is slippery. By applying the brakes over several steps of the pedal, the brake light flashes, becoming a signal to the vehicle behind and preventing a rear-end collision.

2. How to Apply Brakes on a Two-Wheeled Vehicle

① Methods

There are three ways to apply brakes on two-wheeled vehicles.

1. Front-wheel brake operated by a brake lever.
2. Rear-wheel brake operated by a brake pedal or a brake lever.
3. Engine braking operated by releasing the throttle (accelerator) or downshifting (shifting to a lower gear).

※ On some two-wheeled AT vehicles or general motorized bicycles, both the front- and rear-wheel brakes are operated by brake levers (handbrake).

② Points to note

1. Maintain the vehicle body upright with the handlebars straight, and apply the front- and rear-wheel brakes at the same time while engine braking. Maintain the correct riding posture so to prevent tipping forward.
2. When braking on a dry road, apply the front-wheel brake slightly harder. On a slippery road, apply the rear-wheel brake slightly harder.
3. The engine braking is more effective in lower gears. Shifting to a low gear directly from a high gear may damage the engine or cause the rider to overturn. Therefore, downshift one gear at a time.
4. When brakes are applied suddenly, the wheels stop rotating and cause skidding. Therefore, pump the brake pedal several times.

When brakes are applied incorrectly...

• If only the front-wheel brake is applied → Tips forward → Likely to overturn if wheel locks up
• If only the rear-wheel brake is applied → Likely to lock up → Skids if wheel locks up

3. Prohibition against Sudden Braking

1. A rider must not apply the brakes suddenly except when necessary to avoid danger. When sudden braking is unavoidable on an automobile equipped with an antilock braking system (ABS), stepping firmly and fully on the brake in one movement and keeping it depressed are required to activate the system.
2. When driving, do not use the brakes thoughtlessly. Reduce speed gradually using accelerator operation (engine braking) as much as possible when stopping.
3. Sudden braking is dangerous when traveling at high speeds or on slippery roads, because it can cause skidding.

Reference: Antilock braking system (ABS) ABS is a system that attempts to maintain control of the vehicle when brakes are applied suddenly by preventing wheel locking using computer control to maintain the use of the steering wheel and to prevent skidding. Its full effect comes into play on slippery road surfaces such as on winter roads. The pedal may tremble (kickback effect) when brakes are applied suddenly on vehicles equipped with ABS, but this is a normal phenomenon which occurs when ABS has been activated. Keep the pedal depressed. Note that even on slippery road surfaces such as snowy roads, ABS does not function properly unless the pedal is kept depressed. Do not pump the brake.

5. Proceeding Slowly

1. Definition of Proceeding Slowly

Proceeding slowly refers to proceeding at a speed that allows a vehicle to stop immediately.

Reference: "A speed that allows a vehicle to stop immediately" Generally, it is considered to be a speed which allows a vehicle to stop within 1 m of the brakes being applied, a speed of 10 km/h or less.

2. Where to Proceed Slowly

Vehicles must proceed slowly in the following places.

1. Where a "Proceed slowly" sign is present
2. At an intersection where visibility to the right and left are poor — Excluding where traffic is controlled by traffic lights, etc. or when proceeding along a road with the right of way.
3. Near the corner of a road
4. Near the top of an upward slope
5. On a steep downward slope

Reference: When vehicles must proceed slowly In addition to places, vehicles must proceed slowly in the following cases.

1. When proceeding on paths for pedestrian use, with permission. (Refer to p. 53)
2. When passing beside a pedestrian, and a safe distance cannot be secured. (Refer to p. 79)
3. When turning right or left to exit a road. (Refer to p. 62)
4. When passing beside a safety zone where pedestrians are present. (Refer to p. 79)
5. When passing beside a streetcar stopped at a streetcar stop with a safety zone. (Refer to p. 80)
6. When passing beside a streetcar stopped at a streetcar stop without a safety zone when no passengers are getting on or off and when a distance of 1.5 m or more from the streetcar can be secured. (Refer to p. 80)
7. When turning left or right at an intersection. (Refer to p. 60)
8. When entering a road with the right of way or a wide road. (Refer to p. 64)
9. When proceeding in an area with mud or puddles. (Refer to p. 79)
10. When protecting the passage of people with physical disabilities, senior citizens with difficulty proceeding, school children, or preschool children. (Refer to p. 82)
11. When passing beside a school or kindergarten bus which is stopped to let school children or preschool children get on or off. (Refer to p. 82)

Let's Try — Course Content 7: Check your understanding with right/wrong questions. (See page 275 for answers.)

1. The distance traveled from when a driver notices danger and steps on the brakes until the brakes do start to engage is called reaction distance.
2. Stopping distance becoming longer depends more on how well the vehicle's brakes engage, as opposed to being caused by a delay in the driver's operation.
3. Proceeding slowly refers to traveling at a speed that is half or less than the maximum speed limit indicated by traffic signs or pavement markings.
4. Proceeding slowly is not required at intersections with poor visibility when the vehicle is proceeding on the road with the right of way.
5. Proceeding slowly near the top of an upward slope is not necessarily required.
6. To overtake a regular automobile traveling at 60 km/h on a road with no speed limit traffic signs, exceeding this speed momentarily is permitted.
7. When applying brakes on a two-wheeled vehicle, maintain the vehicle body upright with the handlebars straight, and apply the front- and rear-wheel brakes at the same time while engine braking.
8. When braking suddenly on an automobile equipped with an antilock braking system, stepping slowly on the brake is required to activate the system.
9. The stopping distance for a regular passenger automobile traveling on a dry asphalt road at 60 km/h is approximately 44 m.
10. Bringing a vehicle to a stop requires a stopping distance, which is the sum of the reaction distance and the braking distance.

(正: right, 誤: wrong)