Speed limit rules are essential for driving cars and motorcycles. However, many people may not clearly understand the difference between “statutory speed” and “regulatory speed. In this article, we'll explain these important basic rules under Japan's Road Traffic Act in an easy-to-understand way!
1. Speed Basics: Japan's Units and Two Types of Speeds
In Japan, speed is measured in "km/h" (kilometers per hour). (By the way, is it mph (miles per hour) in your country, or also km/h?)
Only vehicles that meet safety and environmental standards set by law can be driven on public roads in Japan. For these "approved vehicles", two main types of speed limits are defined:
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Statutory Speed (法定速度): This is the basic upper limit uniformly set by law, indicating "up to this speed is okay." It applies even without specific signs.
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Regulatory Speed (規制速度): This is the speed limit individually set by signs for specific roads. It's often set lower than the Statutory Speed for safety reasons.
Do these two distinctions also exist in your country's traffic rules?
For example, in Japan:
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The Statutory Speed for general roads is 60 km/h (about 37 mph) for regular cars, and 30 km/h (about 18 mph) for mopeds (motorcycles under 50cc).
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Recently, as a safety measure for residential and living areas, there's a movement to set the Regulatory Speed to 30 km/h in certain areas (zones).
How do you feel about Japan's maximum speed on general roads compared to your country's standards?
2. Why Do Rules Exist? A Background of Strictness
In Japan, the criteria for judging "dangerous driving" are already very strict, especially in distinguishing between "accidental mistakes (negligence)" and "intentional acts (deliberate)". With upcoming changes to the Road Traffic Act under discussion, offenses like drunk driving and speeding may face even tougher penalties, reflecting a continued focus on traffic safety.
Vehicles have been developed to achieve faster travel and greater convenience, but increasing speed requires comprehensive safety assurance, including not just vehicle performance but also road structure and surrounding environment. Without ensuring safety, speed cannot be easily increased.
3. Even with High-Performance Vehicles, Caution for Others is a Must
Even if your car or motorcycle performs well, the road is shared with pedestrians, cyclists, and even electric kick scooters — meaning not everyone can move safely through the same space.
That's why Regulatory Speeds exist, and drivers have a duty to protect the safety of others and prevent accidents.
In Japan, a high level of safety awareness is required under strict traffic laws, but accidents at intersections in urban and residential areas, and accidents during right/left turns, are still common. What are the common types of traffic accidents in your country that people are warned about?
By the way, in Japan, the standard for moped brake performance is "to be able to stop within 6 meters from a speed of 20 km/h." This shows an attitude of strictly managing vehicle safety from the design stage.
Regardless of vehicle type, daily maintenance is fundamental for safety. Checking brakes and tires is crucial, and aspects like the engine's condition and static electricity countermeasures are often overlooked. Utilizing special anti-static items that can reduce static electricity's impact to bring out the engine's original performance is also recommended.