Why is there a small mirror on the hood of right-hand drive cars?

For most drivers accustomed to driving on the left, the sight of a right-hand drive car entering heavy traffic may seem exotic. However, an even stranger element is often additional mirror, mounted on the front fender or hood. This accessory is not a decorative adornment or a fashion statement, but is a vital design element dictated by strict traffic rules and viewing geometry.

The essence of the problem lies in the location of the steering wheel. When the driver is on the right and oncoming traffic is moving from the left, standard side view mirrors simply cannot provide a full view of blind spots, especially when overtaking. The fender (or hood) mirror is designed to monitor the lane directly below the driver and just behind the front bumper, which is critical when maneuvering in tight spaces. Without this device, safely overtaking on a two-lane road would be almost impossible without entering the oncoming lane “blindly.”

In this article we will analyze in detail the physics of the process, the legal requirements of various countries and the technical features of installing such systems. Understanding the principles of operation of these mirrors is necessary not only for owners JDM (Japanese Domestic Market) cars, but also for those who plan to drive or operate such equipment in countries with left-hand traffic.

Viewing geometry and the problem of blind spots

The main reason for the appearance of additional mirrors lies in the fundamental asymmetry of road traffic. In countries that drive on the left, such as Japan, the UK or Australia, overtaking is done in the right lane. The driver sitting on the right is physically removed from the center of the road, which creates a huge “blind zone” in front and on the sides of the car, which cannot be covered by a standard side mirror.

The standard mirror located on the door is aimed at viewing the lane adjacent to the car and the distant space behind. However, the viewing angle is limited by the body pillar and the convexity of the wing itself. Additional mirror, carried forward on a long arm, shifts the point of view, allowing the driver to see into an area that would normally be hidden from view.

This is especially critical when overtaking begins. The driver must be absolutely sure that there is no vehicle in the right lane that he can cut off. An ordinary mirror only shows the tail of the car in front, but does not provide an understanding of whether there is space to change lanes right now.

⚠️ Attention: An attempt to overtake in a right-hand drive car without using additional mirrors or without first turning your head (which is difficult due to the design of the interior) is statistically more likely to lead to head-on collisions or tangential impacts on the right side of the body.

In addition, the body geometry of modern cars often sacrifices visibility for the sake of aerodynamics and design. Thick A-pillars and blocked windshields create additional obstacles. The remote mirror compensates for these shortcomings, becoming a kind of “second floor” for the driver’s eyes.

Legal requirements and safety standards

Installing mirrors on the wings is not just a recommendation from engineers, but is often a direct requirement of law. In Japan, according to traffic rules and technical regulations, a car is required to provide the driver with a certain viewing angle. If standard equipment does not allow achieving standard indicators, the installation of additional elements becomes mandatory.

In Europe, where many Japanese cars are also imported, the requirements are even stricter. EU directives clearly regulate the size of the field of view for various classes of vehicles. Upon certification Right-Hand Drive (RHD) version of the car for a market where it was not originally designed as the main one, the presence of such mirrors often becomes a condition for admission to public roads.

• 🚗 Japan: Requires visibility of the overtaking lane at a distance of up to 30 meters in front of the car when driving at a speed of 60 km/h.
• 🇬🇧 UK: DVLA standards require mirrors to eliminate blind spots, especially for commercial vehicles and non-standard vehicles.
• 🇦🇺 Australia: The ADR (Australian Design Rules) rules require visibility into the lane along which the maneuver will be made, which is physically impossible without remote elements on wide vehicles.

The absence of such mirrors can lead to problems when passing a technical inspection or even fines from the traffic police. Inspectors have the right to stop the car if they consider that the design does not provide safe driving.

⚠️ Attention: When purchasing a right-hand drive car “from under control” or after an accident, make sure that the mirror brackets are certified. Self-made structures can be recognized as a malfunction affecting safety, with all the ensuing consequences.

It is important to note that requirements may vary depending on the year of the vehicle. Older models could only be equipped with one mirror, while modern standards often require a pair of symmetrical or specific angled mirrors.

Design features and types of fastenings

The engineering solution to the vision problem has given rise to several types of structures. The most common option is a mirror mounted on a long metal bracket that is attached to the front fender. This arrangement brings the plane of reflection forward as much as possible, minimizing distortion from the topography of the wing and hood itself.

There are also models integrated into the main structure of the side mirror. In this case, an additional convex element of a smaller size is installed on the outside of the main body. Although this solution looks more aesthetically pleasing, it is less effective due to its proximity to the body and limited coverage angle.

Remote mirror mounts are usually made of chrome-plated steel or durable plastic with a metal core. They must withstand vibration at high speeds and exposure to weather conditions. Bracket often has tilt adjustment, allowing the driver to adjust the viewing angle to suit his height and position.

Some manufacturers such as Toyota or Nissan, in the factory version they offer electronic versions of such mirrors with heating and electric folding, which significantly increases the comfort of use in winter.

Effect on aerodynamics and fuel consumption

Any protruding element disrupts the laminar air flow flowing around the car body. Remote mirrors sticking out to the sides create additional aerodynamic drag. At high speeds, this leads to increased fuel consumption and the appearance of extraneous noise in the cabin.

Engineers try to minimize this effect by streamlining the brackets and using vortex-reducing profiles. However, it is impossible to completely eliminate the effect on aerodynamics. For owners, this means that on the highway at speeds above 100 km/h, fuel consumption may increase slightly.

In addition, the windage of such mirrors makes the car more sensitive to side winds. When overtaking large trucks, the driver may experience a sharp jerk or fluctuation in course caused by wind shadow and air currents from the truck affecting the mirror area.

• 🌬️ Noise: At speeds above 110 km/h, a whistle or hum may appear from the mirror pillars.
• ⛽ Consumption: An increase in resistance can add 0.2–0.5 liters to consumption per 100 km.
• 🚿 Washing: Automatic brush washers can damage outriggers, so manual mode is recommended.

Despite these disadvantages, the security provided by such mirrors completely covers the inconvenience. Losing a few percent of efficiency is a small price to pay for preserving the life and integrity of the car.

Comparison with modern camera systems

In the digital age, the question arises: why use bulky mirrors when you can use cameras? Indeed, modern cars are increasingly equipped with all-round visibility systems. However, the old JDM models and under strict regulations, mirrors remain the only solution.

Cameras have a number of disadvantages: they can fog up, be splashed with dirt, and be blinded by the oncoming sun or headlights at night. A mechanical mirror, especially one with a high-quality anti-reflective coating and heating, works predictably in any conditions. The image in the mirror gives an instant understanding of the speed at which objects are approaching, which is sometimes lost when the video signal is delayed.

However, the trend is to replace mirrors with cameras (Camera Monitor Systems) is gaining momentum. Japan has already allowed the use of such systems on trucks and cars. This improves aerodynamics and reduces noise. But for used car fleets, fender mirrors will remain relevant for many years to come.

⚠️ Attention: If you are installing a camera instead of a mirror on an older car, make sure the viewing angle complies with your country's traffic regulations. Standard wide-angle cameras may not be certified as replacements for rear view mirrors.

Until technologies become widely available and legally approved everywhere, the “horns” on the wings of right-hand drive cars will serve as a faithful guardian of road safety.

Correct setup and operation

Having an additional mirror is useless if it is not configured correctly. Many drivers mistakenly position it so that they can see the rear wing of their own car. This is wrong. The purpose of a mirror is to show what you are don't you see into the main mirrors.

To set it up correctly, you need to sit in your usual driving position. The main side mirror is adjusted so that the edge of the body occupies a minimal part of the field of view (about 10-15%). The additional mirror on the wing should cover the area that is immediately outside the view of the main mirror, going forward and to the side.

A common mistake is using mirrors that are too convex (“panoramic”). They provide a wide viewing angle, but greatly distort the distance to objects. The car in such a mirror appears further away than it actually is, which can provoke a dangerous maneuver. It is better to use mirrors with minimal curvature or flat ones, getting used to their viewing angle.

Regular cleaning of the surface from dirt, insects and reagents is a must. A dirty mirror creates the illusion of a clear view, but actually hides danger. Use special anti-rain sprays to improve water-repellent properties.

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