How to Park a Car Safely? - Gevin Enterprises Co., Ltd.
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How to Park a Car Safely?

    Why Learn the Way to Park?

    Any driver needs to park his/her car. While most driving lessons focus mainly on how to drive, little emphasis is put on the best practices on how to park cars. There are tricks on how to drive and place the car well in a parking space, but these are still ultimately related to the person’s driving experience and skills. The best practices for the final procedures of parking the car once the car has stopped, however, does not require experience nor skill, but common sense and knowledge. This article will focus on the two most commonly available transmission types on the market today: manual transmission, and automatic transmission.

     

    Most People Do Not Park Cars the Correct Way

    With automatic transmission playing a significant role in the automotive transmission market, most people actually do not park properly. Drivers who drive with manual transmission are most likely trained in the correct way, but there are still disputes on how to park with a manual transmission, which will also be discussed in the article.

     

    Automatic Transmission: Does Putting the Gear in “Park” Work?

    Drivers who are trained to drive with automatic transmission are told to put the car in “Park” (P) gear first, then apply the hand brake. Some drivers even simply put the gear in “P” mode and forget the hand brake.

    In order to see whether this practice is good for your car, we need to understand the basic mechanisms behind the “P” gear. The transmission is a set of complicated array of gears. The gears connect the engine to the drivetrain to power the wheels. The engine can only work so hard – typically 6,000 revolutions per minute (RPM) or so. If the car had only one gear, it would not run very fast, because maximum RPM would be reached within seconds. The gears allow the car to delivery sufficient power and yet allow the car to run at speed, making the car a flexible vehicle.

    Automatic gearbox changes the gear automatically via computer control. “P” gear is found in automatic transmission and not manual transmission, because there is a clever device to help the forgetful driver. When the gear is in “Park” mode, a metal notch comes between the gear teeth and stops the gear from rotating, thereby stopping the car from rolling further.

    Car automatic transmission Park gear depiction

    Not a very sizable (in fact, rather small) metal notch is used to stop the gear in P gear. When parked on a slope with only P gear and no hand brake, the driver will experience the car rolling down a little, then stops and bounces back and forth a little before becoming still. This is the metal notch trying to keep the car from rolling.

    It is basically a general consensus that parking with only P gear without hand brake is potentially damaging to the gearbox. The risk increases with the slope angle. It is bad practice to use only P gear to park the car.

     

    Manual Transmission: Park in First Gear or in Reverse Gear?

    Manual transmission does not have “Park” gear. The gear stick is placed in the middle, horizontal line between gears for “Neutral” (N) gear, or placed in one of the gears. This means none of the gear selections will help stop the car from rolling. Put the car in neutral, and the car will roll as freely as it can without hand brake. It is generally debated over whether to park the car in first gear or in reverse gear.

    Since none of the gear selections in manual transmission can stop the car from rolling, the purpose of putting the car in gear when parked is to restrict the rolling of the car by as much as possible should the hand brake fail. The gear ratio from the engine to the wheels (the gear that ultimately drives the wheels is called “final drive”) determines how much restriction will be imposed on the rolling car. For example, a gear ratio of 3.8:1 means the engine has to revolve 3.8 times to turn the wheel 1 time. Ratios between 3~4 to 1 is typically found in first gear. Second gear is typically around 2+ to 1. Reverse gear ratio is typically lower than first gear.

    Gear ratios matter when it comes to rolling cars. When put in gear, it is usually the engine that drives the car in motion. However, when the car is at speed, or is rolling down a slope with the engine at idle, the wheels become the driving source – the momentum of the car pushes the engine and makes the engine revolve higher than idle. The engine, being driven by the car, would restrict the car’s roll speed or slow the car down due to friction of the pistons (very low friction) and the sucking of the air in and out of its cylinders (which causes the greatest friction force).

    The practice of using lower gears (high gear ratios) to slow the car down or restrict the car’s free roll speed is called “engine brake”. Engine brake is advised for going down a slope or slowly the car down at high speeds, since it reduces brake load significantly and reduces the risk of brake failure. This is especially important when driving mountain roads that may take long to drive. Car crashes are often observed because the driver fails to utilize engine brake and cause the brakes to overheat, leading to brake failure and ultimately car crash. Automatic transmission also allows the driver to engage engine brake via manual selection of the gears. Some automatic transmissions have computers that are smart enough to detect downslope and choose a more optimal gear for the road condition.

    Higher gear ratios (lower in gear) are more efficient for engine brake. For example, if it takes the engine 3.8 revolutions to turn the wheel once, the reverse works. The car’s momentum making wheel spin once will make the engine revolve 3.8 times. The more it takes for the engine to revolve with one wheel spin, the more friction is generated, thereby braking the car more efficiently.

    Having known that a car should be restricted as much as possible when parked, it is therefore best practice to choose the gear with the highest ratio. This is typically the first gear, which has a higher gear ratio than reverse gear.

     

    How to Park Properly?

    Parking on the plane

    Manual transmission:

    Since the car doesn’t roll by itself on a plane, it is okay to park in neutral gear or in any gear for manual transmissions, as long as the hand brake is applied.

    Automatic transmission:

    Again, the car doesn’t roll by itself, so parking the car with or without the hand brake in P gear is fine. It is still best practice to apply the hand brake.

     

    Parking on a slope – facing up

    Manual transmission:

    Put the car in first gear to restrict the car by as much as possible, and apply the hand brake. Turn the wheel so that the car will roll towards the nearest curb or anything that may stop the car, and turn the steering wheel until it locks. This will restrict the car’s movement by as much as possible and reduce damage to a minimum.

    Automatic transmission:

    Turn the wheel so that the car will roll towards the nearest curb or anything that may stop the car until the steering wheel locks. Then put the gear to NEUTRAL and apply the hand brake. Let go of the brakes to ensure that the hand brake has been applied enough to stop the car from rolling. THEN put the gear in Park.

    It is a general misunderstanding to think that the brake will already work when the hand brake is applied. If the car doesn’t roll and the hand brake is applied, the hand brake is still not doing anything to stop the car yet! This may be counter-intuitive, but it takes a little bit of movement to “activate” friction in the brake, in order for the brake to stop the car.

    How does this work? A simple demonstration will help you understand. Clap your hands together, and move both your hands forward and back a few times. Do you feel your hands rubbing against each other? No, they’re merely touching one another. There is NO friction. Now move both your hands again, this time make your right hand move a little more than your left, but still making them move together. You will feel friction, and this friction is stopping the hand from sliding against each other.

    This is exactly why when you park the car on a slope and put the car in P gear first, then apply the hand brake, the car will still roll a little before coming to a stop when the brakes are released. It will still cause stress on the gearbox, although the hand brake has generated friction. Without any movement from the car, the brakes WILL NOT generate friction. This is why you should ALWAYS APPLY HAND BRAKE in NEUTRAL gear FIRST, make the car roll to a stop, then put the gear in Park. This is the best practice for automatic transmissions.

    If you have wheel chocks available, put the wheel chocks against the wheels that are lower down the slope. Have at least two wheel chocks. Putting four wheel chocks, one for each wheel, is even better.

    In summary:

    • Turn the steering wheel toward anything that may stop the car as soon as possible, until the wheel locks.
    • Put the gear in Neutral.
    • Apply the hand brake.
    • Release the brake pedal and make the car roll a little until it completely stops.
    • THEN put the gear in Park.
    • Put at least two wheel chocks (one for each wheel) against the wheels that are lower down the slope.

     

    Parking on a slope – facing down

    Manual transmission:

    Some advise that the car be put in reverse gear when the car is parked facing down the slope. It seems to make sense, since the car in reverse gear would have the engine rotate the wheels in reverse direction, thereby restricting the car even more. However, the engine will eventually be turned off when the car is parked! Without the engine rolling, it makes no difference whether the car is put in reverse or first gear, because there is nothing from the engine to rotate the wheels. If the car rolls, the wheels will be driving the engine.

    Even in reverse gear, the engine still revolves in the same direction. It is the gear setting that make the wheel spin in reverse direction, not the engine itself. When the engine is turned off, and the car rolls forward in Reverse gear, instead of going backwards, the engine will still be revolved by the wheels in the opposite direction it would be revolving when fired up. If the engine is turned on while revving in the opposite direction, the engine may suffer some damage. It is best to stop the car fully with brakes.

    The only gear that will restrict the car’s rolling by as much as possible is the gear with the highest ratio, which is the first gear, not the reverse gear. Should the driver make it in the car before it rolls down the hill too fast, the driver will have to apply the hand brake more to stop the car. If the hand brake fails, the driver will need to apply the regular brakes. However, regular brakes will not work without the engine on, because modern brakes use hydraulic pump to power the brakes. Without the engine on, there is nothing to power the hydraulic system. The only way to make the brakes work is to pump the brake many times to get air in there and increase brake pressure. This is inefficient and definitely not the first option in an emergency.

    With the wheel turned towards the curb or anything closest to the car that may stop the car, the car would suffer comparatively little damage (or none) without rolling too far. However, if the driver forgets to do this, would it be better for the car to be in Reverse gear? The only possible reason to be in the less efficient Reverse gear is so that the driver may turn on the engine and use Reverse gear counter the car’s sliding forward.

    This is not good practice. Turning the engine on is to apply the brakes and make the car stop if the hand brake fails. The tires will most likely spin out and lose grip if high engine revs are used to counter the car’s rolling. Losing grip means losing control. In the end, it is not countering the car’s sliding down the slope with the engine that will ultimately bring you to safety. It is hitting the brakes. Before you’re able to turn on the engine to brake the car, the priority is to restrict your car’s movement. This means first gear, and locking the steering wheel toward anything that may stop the car the soonest.

    If you have wheel chocks available, put the wheel chocks against the wheels that are lower down the slope. Have at least two wheel chocks. Putting four wheel chocks, one for each wheel, is even better.

    Conclusion:

    • Turn the steering wheel toward anything that may stop the car as soon as possible, until the wheel locks.
    • Put the gear in FIRST gear
    • Apply hand brake
    • Put at least two wheel chocks (one for each wheel) against the wheels that are lower down the slope.

    Automatic transmission:

    The same as when parking facing up the slope.

     

    Parking on a sideways slope

    The same practice should be done as the above instruction, whether manual or automatic transmission. The problem with parking on a sideways slope is that if the car tilts too much, it may roll over. The car’s weight will also cause stress on the wheels and axles at an angle.

    How do we prevent the car from rolling over sideways? Try and park at a slanted angle, instead of facing perpendicularly to the slope. It may also matter whether you should have your rear wheels down the sideways slope, or your front wheels. Normally it’s the front wheels, because most cars put the engine in the front. The engine is the heaviest component in a car, so the weight distribution in most cars is forward-biased, meaning the front wheels take more weight than the rear wheels. The heavier side should be placed lower down the slope when the car is parked at a slanted angle. This reduces risk of rolling over.

    Cars such as BMW 3, 5, 7-series, etc. have 50:50 weight distribution over the front and rear wheels. The car is almost perfectly balanced. In this case, having the front or rear wheels lower down the slope when parked at a slanted angle does not matter.

    Lamborghini, Toyota MR-2, Ferrari, Lotus, and the like have the engine in the middle, or more specifically, in the rear seat of most cars. This is called an MR setup, or Mid-engined, Rear-wheel-drive. Weight distribution in these cars is usually a little more biased towards the rear wheels. In MR cars, the car should be parked with the rear wheels lower down the slope to reduce the risk of rolling over. However, the risk of rolling over in MR cars are reduced with or without slanted parking, because MR cars are always sport cars. They already have a proportionally wider body and lower chassis to make them more stable against rolling sideways, a necessity during racing.

    Porsche 911 is an odd one. Very few cars nowadays place the engine in the rear, where the boot space is usually found. 911 is an RR car, or Rear-engined, Rear-wheel-drive. The most famous RR car besides Porsche 911 is the classic Volkswagen Beetle. RR cars are difficult to control. Newer 911 models are all-wheel-drive, although the engine is still in the rear. In RR cars, the weight is much more biased toward the rear, so have the rear wheels lower down the slope when parking at a slanted angle.

    If you have wheel chocks available, put the wheel chocks against the wheels that are lower down the slope. Have at least two wheel chocks. Putting four wheel chocks, one for each wheel, is even better.

     

    Conclusion

    Utilizing the best practices in the final steps of parking a car does not require skill, but common sense, knowledge, and reminding oneself of the correct steps to park the car. Manual and automatic transmissions are different. Always park the manual car in first gear. In automatic cars, always put the gear in Neutral, apply the hand brake, then put the gear in Park. When parking on a slope, mind whether the car faces up or down the slope, and turn the wheels towards anything that may stop the car from rolling, and turn until steering wheel locks. Hand brake should always be the first and most important component under all parking scenarios. Extra precautionary practice can be performed with placing at least two wheel chocks, one for each wheel, against the wheels that are lower down the slope. Having four wheel chocks is even better.

    We recommend GVP-5157 Plastic Wheel Chock for the task. The wheel chocks are cost-effective, lightweight, durable, compact, and functional. Wheel chocks prevent the car from rolling should the hand brake or anything fail. They also prevent the car from having to run into something before it stops, keeping the car from even the slightest damage. A very useful and helpful automotive tool indeed.

    Written on January 13, 2015 at 11:48 am