Why Japan's Expressways Are Worth Knowing Before You Drive

Renting a car in Japan opens up scenic routes and hidden destinations that public transport cannot reach. However, Japan's expressway network comes with rules and systems that differ from what drivers in other countries may expect. Understanding these before you hit the highway will save you time, money, and stress.

The ETC Card: Your Key to Smooth Toll Payments

Japan's expressways are toll roads, and the Electronic Toll Collection (ETC) system is the most efficient way to pay. When you rent a car, the vehicle will almost certainly have an ETC device installed in the dashboard. What you need to add is an ETC card, available as an optional rental item at most car rental counters. Request one when you book your vehicle.

Using the ETC system is straightforward. Insert the card into the in-car reader before driving, and the device will give an audible confirmation. When approaching a toll gate, look for the purple-coloured ETC lane rather than the green general lane. Slow down to 20 km/h or below as you pass through — the barrier lifts automatically if your card is valid. All toll charges are settled when you return the rental car.

The ETC card also unlocks time-based discounts. Driving between midnight and 4 a.m. qualifies for roughly 30% off on many expressways. Weekend and public holiday discounts are also available. For longer road trips, some rental companies offer regional Expressway Passes — such as the Hokkaido Expressway Pass or the Kyushu Expressway Pass — allowing unlimited expressway use within a specific region for a flat fee.

Speed Limits on Japanese Expressways

The standard speed limit on Japan's national expressways is 100 km/h for ordinary passenger cars, with a minimum of 50 km/h on the main lanes. However, not all high-speed roads share the same limit. Urban motorways such as the Tokyo Metropolitan Expressway are legally classified differently, and the default speed limit on these roads is 60 km/h unless a digital sign indicates otherwise. Many foreign drivers receive fines on the Tokyo Metropolitan Expressway by assuming the limit is 100 km/h. Always check posted signs.

Keep to the left lane for regular driving. The rightmost lane is a passing lane only — staying in it after overtaking is a traffic violation. Driving on the road shoulder is strictly prohibited except in genuine emergencies.

Service Areas and Parking Areas

Japan's expressways are well supplied with rest facilities. Service Areas (SA) are larger stops offering restaurants, convenience stores, gift shops, petrol stations, and clean restrooms open 24 hours. Parking Areas (PA) are smaller and may offer only restrooms and vending machines.

• Follow the green directional signs with a "P", coffee cup, or "i" symbol to find the next rest stop.
• Park in the correct bay for your vehicle type — trucks, buses, and motorcycles have designated areas.
• Refuel at SA petrol stations before long stretches with no service facilities. Running out of fuel on an expressway is a punishable offence in Japan.

What to Do If Your Car Breaks Down

If your car breaks down, move the vehicle to the road shoulder or an emergency bay if possible and turn on your hazard lights immediately. Place an emergency warning triangle at least 50 metres behind the vehicle — this is legally required on expressways. Do not remain inside the car. Exit through the left-side door and wait behind the guardrail, away from traffic. Emergency telephones are installed every kilometre along the expressway. You can also dial #9910 from your mobile phone.

Key Rules to Remember

• No U-turns or reversing on expressways. If you miss your exit, proceed to the next interchange and ask toll staff — they can arrange a legal U-turn route at no charge.
• Seatbelts are mandatory for all occupants at all times.
• Mobile phone use while driving is illegal and carries heavy fines.
• Vehicles with engine displacement of 125cc or below are not permitted on expressways.

Japan's expressways are among the safest in Asia. With the right preparation — particularly around the ETC card and speed rules — your highway driving experience will be smooth and genuinely enjoyable.

Why Summer Driving in Japan Demands Extra Caution

Japan's summer is one of the most demanding driving environments in Asia. From late June through early September, the combination of intense solar radiation and high humidity creates conditions that can be genuinely dangerous for drivers. Temperatures regularly exceed 35°C across the country, and inside a parked car, the situation becomes far more extreme. According to testing conducted by the Japan Automobile Federation (JAF), a black vehicle left in direct sunlight at an ambient temperature of 35°C can reach an interior peak of 57°C, with the dashboard surface climbing to 79°C. Even a white car under the same conditions can hit 52°C inside. These are not temperatures that humans, pets, or children can safely tolerate, even briefly.

Never Leave Anyone in a Parked Car

One of the most critical findings from JAF's summer research is how quickly conditions deteriorate once the air conditioning is switched off. In their tests, the heat stress index inside a parked car reached a dangerous level within just 15 minutes of the engine being turned off. For infants and elderly passengers, whose body temperature regulation is less efficient, this window is even shorter. Never leave children, elderly individuals, or pets inside a parked car during summer, even if you plan to return within a few minutes. Opening windows by 3 cm only reduces peak interior temperature from 57°C to 45°C, which remains life-threatening.

Preparing Your Rental Car Before You Drive

Before setting off on a summer road trip in Japan, there are several practical steps every rental car driver should take. First, use a sunshade on the windshield whenever the car is parked. While sunshades alone cannot prevent dangerous heat buildup, they reduce dashboard temperatures and make the initial cool-down faster once you start the air conditioning. Second, open all doors for 30 to 60 seconds before entering a car that has been sitting in the sun. This allows trapped hot air to escape and reduces the time your air conditioner needs to reach a comfortable temperature. Third, check that the rental car's air conditioning is functioning properly before leaving the lot. In summer heat, a malfunctioning AC is not merely uncomfortable — it is a safety issue.

Staying Hydrated and Alert on the Road

Driving in heat increases the physical and cognitive demands on the driver. Dehydration, even at mild levels, impairs concentration and reaction time. Keep a large bottle of water within easy reach at all times, and drink regularly rather than waiting until you feel thirsty. Avoid energy drinks and alcohol entirely while driving, as both accelerate dehydration. Plan your route to include rest stops every 60 to 90 minutes, especially during the hottest part of the day between 10:00 and 15:00. Japan's highway service areas (SA) and parking areas (PA) are well-equipped with vending machines, convenience stores, and shaded rest areas, making them ideal spots to cool down and rehydrate.

Managing the Air Conditioning Effectively

Running the air conditioning not only lowers temperature but also removes moisture from the cabin air, which makes a significant difference to driver comfort and alertness. Set the temperature to around 25°C to 27°C rather than the coldest setting, as extreme cold can cause drowsiness and make the transition to outdoor heat more physically stressful. Direct the vents toward the lower body rather than the face to maintain alertness. On long drives, switch the AC to fresh-air mode periodically to prevent carbon dioxide buildup inside the cabin.

What to Do If You Feel Unwell While Driving

If you begin to feel dizzy, nauseous, or unusually fatigued while driving, pull over safely at the nearest rest area or convenience store parking lot. Turn the air conditioning to its maximum setting, drink cold water, and apply a cold, wet towel to your neck and wrists. Japan's nationwide emergency number is 119 for ambulance services. If symptoms do not improve within 15 to 20 minutes, call for help immediately. Heat exhaustion and heat stroke can escalate rapidly, and it is always better to stop and seek assistance than to push on and risk an accident.

Summer Driving Checklist

• Carry at least one liter of water per person per hour of planned driving.
• Use a windshield sunshade whenever parked in direct sunlight.
• Never leave passengers or pets in a parked car with the engine off.
• Take a rest break every 60 to 90 minutes, especially between 10:00 and 15:00.
• Check the rental car's AC before departing from the rental counter.
• Know the emergency numbers: 119 for ambulance, 110 for police.

Japan's summer roads are beautiful and well-maintained. With the right preparation, a summer road trip can be a genuinely memorable experience. The key is to respect the heat, plan your stops, and keep yourself and your passengers hydrated and comfortable throughout the journey.

Understanding Japanese Road Signs and Markings

Driving a rental car in Japan offers an incredible opportunity to explore scenic routes that are often inaccessible by public transportation. However, for foreign drivers, navigating Japanese roads requires a solid understanding of local road signs and markings. Since English translations are not always available on every sign, especially in rural areas, familiarizing yourself with these essential visual cues is crucial for a safe and stress-free journey.

Japan follows the left-hand traffic system, meaning the driver's seat is on the right side of the vehicle. While this might take some getting used to for drivers from countries with right-hand traffic, understanding the road signs is equally important. The Japanese traffic system is highly organized, and strictly adhering to these rules ensures your safety and the safety of pedestrians and other drivers.

The Iconic "Stop" Sign (Tomare)

One of the most critical signs you must recognize is the Japanese "Stop" sign. Unlike the red octagonal signs common in many Western countries, the Japanese stop sign is an inverted red triangle with the white characters "止まれ" (Tomare) written on it. In recent years, English translations have been added to some of these signs in major cities, but you should not rely on this everywhere.

When you encounter this sign, you must bring your vehicle to a complete stop just before the solid white stop line painted on the road. Failing to stop completely is a serious traffic violation and a leading cause of accidents involving foreign drivers at intersections without traffic lights. After stopping, you must visually check both directions for oncoming traffic, bicycles, and pedestrians before proceeding.

Traffic Lights and Unique Arrow Signals

Traffic lights in Japan are generally horizontal and are placed on the opposite side of the intersection. The sequence is standard: green, yellow, and red. However, there are specific rules you must follow. In Japan, you cannot turn left on a red light unless there is a specific sign or a green arrow indicating it is safe to do so. A red light means all traffic must stop.

You will frequently see green arrow signals below the main traffic lights. If the main light is red but a green arrow is illuminated, you may proceed only in the direction indicated by the arrow. For example, a green right arrow allows you to turn right, but you must still yield to oncoming traffic and pedestrians. Always prioritize pedestrians, as they have the right of way at crosswalks.

Speed Limits and Regulatory Signs

Speed limits in Japan are generally lower than in many Western countries. On ordinary roads, the speed limit is typically 60 km/h, but in urban areas and residential zones, it is often reduced to 30 km/h or 40 km/h. On expressways, the limit is usually 100 km/h, though some sections may allow up to 120 km/h. Speed limit signs are round with a white background, a red border, and blue numbers.

Another important regulatory sign is the "No Entry" sign, which is a red circle with a white horizontal line. This indicates that vehicles cannot enter the road. Additionally, the "Slow Down" sign (徐行) is an inverted red triangle similar to the stop sign but with different characters. It requires you to reduce your speed to a level where you can stop immediately if necessary, usually around 10 km/h or less. Being mindful of these rules is the key to an enjoyable trip.