If I come to a stoplight that I think is going to last long, I shift into the parking gear. This drives my wife crazy. She thinks that I am increasing the wear on the parking gear by doing this. I think that’s nonsense, that if instead I kept my foot on the brake, my leg would get tired and I might add to the wear on the brakes. Anybody have a comment?
Your wife is right. Brakes only wear when they’re actually stopping the car. When the car is already stopped, brakes just hold it there and don’t wear.
Shifting the transmission between drive and park, however, does put wear on it - not a huge amount, but some is more than none.
And, tongue somewhat in cheek, if your leg gets tired holding the brake pedal at a stoplight, you need to hit the gym 
Keeping your foot on the brake pedal is not adding to wear on the brake pads.
In the long run, it is possible that you might slightly shorten the life of the master cylinder and/or calipers, but the brake pads experience no wear whatsoever when the vehicle is stopped.
As to your leg…only you know if this is a serious issue for your body.
And…give this scenario some thought:
What if another car rear-ends you while you have the transmission in Park?
Do you really want to have to repair the transmission, in addition to having bodywork done?
I think it is a bad idea to put the car into park at a stoplight, but the reasons aren’t mechanical.
Someday you may forget the car is in park and when you go to move forward the motor will rev but you won’t move. Then you’ll realize cars behind you are waiting and you’ll go to quickly put the car in gear and perhaps get it in reverse and hit the car behind you. Or you’ll put it in drive but will already be pushing the gas petal so the transmission might clunk into gear and lurch the car forward. If the transmission engagement is violent enough you could damage the transmission.
If you are hit from behind with the car in park there could be some damage to the transmission in addition to body damage.
A tired leg on a modern car with power brakes is a poor reason for putting the car in park at a stoplight.
No offense, but if your legs are getting just by pushing the brake pedal in, then you may have a medical issue, and may not be fit to drive.
Just Wondering . . . When You Park Overnight Do You Remove The Battery And Drain The Fuel System ?
It’s simple. Park is for parking. One is not supposed to park at an intersection. Standing, with engine running and brakes applied, is appropriate at a red traffic light.
CSA
Why sweat the small stuff? And this idiosyncrasy is small stuff, don’t you think.
" She [Wife] thinks that I am increasing the wear on the parking gear by doing this. "
Your wife makes a good point. If you do this quite a bit over a long period of time I’m pretty sure you will wear something more than normal. Linkage parts will probably become worn and sloppy. I’d bet that when the manufacturer of your car designed and tested the gearshift components that they didn’t plan on this driver behavior. I wouldn’t blame them if you have problems.
On the other hand, the braking system was designed and tested to be used the way normal drivers use it.
CSA
Your wife should refuse to ride with you until this habit is stopped.
The brakes are not being worn by sitting there with your foot on the brake. Other than the excessive wear on the shifter mechanism and parking pawl in the transmission, the bigger issue is the creation of a distraction for the drivers behind you.
When you shift from P into D you pass through R and someone may not only be irritated by seeing those backup lights come on they may incorrectly think you’re about to move and in turn they may accelerate and inadvertently run into you.
There may also reach a point where the shift mechanism has a problem and you’re sitting there blocking a busy intersection because the shifter is locked into PARK and won’t come out. That will endear you to many motorists.
A better idea is to be in N (neutral), and keep your foot on the brake. Reason being when it is kept in Drive and your foot is on the brake the transmission is fighting the brakes. Otherwise you risk damaging the throwout bearings when you keep it in drive with your brakes on.
When the light is green you slap shifter from n to d and off you go.
Drewman…FYI…there is no throwout bearing in an automatic transmission equipped vehicle.
It would drive me crazy too. First issue is if you are hit from behind while you are sitting there, the damage and injury will be more severe. Secondly, if you are watching behind you, you will not be able to get out of the way if you see someone will likely hit you. Third, on my car, putting it in park unlocks the doors which is not a good idea to have unlocked doors while sitting at a stop light. Maybe if you are in heavy heavy traffic or are stopped for a long time, putting it in neutral would be ok but not park.
Drewman, in addition to Missileman’s comments you should also know that in a properly operating modern car the transmission is not fighting the brakes. There’s a fluid coupling device called a “torque converter” between the engine and the transmissio input shaft. It’s like a big bagel sliced and hollowed with vanes in both sides. It’s filled with fluid, and when the engine is running, the tranny in D, and the car being held by the brakes, the fluid absorbs the energy being generated at the engine output shaft and converts it to heat, which is then dissipated by the tranny cooling system. Modern ones are so well designed that many cars will actually roll backwards if you stop on a hill.
I’ve attached a link to explain it. There are countless others if you find this one hard to understand.
Brakes are cheap, transmissions are expensive
It’s also a safety thing. Kinda dangerous to be sitting in traffic and not be in cotrol of your vehicle. In park you don’t control when you take off, like when you REALLY NEED to get going. In an emergency when you drop the trans in D it is very easy to give it gas before it’s fully engaged and obviously thats not good.
Today’s shift linkages and mechanisms can be complex and difficult and expensive to repair…Put it in drive and leave it there…Or some day it will refuse to move into drive…
Life is too short to worry about things like this, I think.
Just keep your foot on the brake.
Your wife is correct. And wise. The car was designed to be driven in the manner she suggests.
And…this is your wife’s wish. If you fail to follow her her advice, you’d best get used to being in the “doghouse”. And, if the tranny linkages does wear out prematurely, you’d best practice your “puppydog” face.
Sitting with the brakes on does not wear the brakes and sitting in park does not wear the “Park Gear” as you call it. Shifting from Park to drive does however put a little jolt to the drive train, although very little. There is a country song called “Shut up and drive” not a bad idea.
I don’t like the idea of relying on the foot brake to hold the car still. But why do people use the park gear instead of yanking the parking brake handle and leave it at that? When I drive an auto, I do yank the brake handle at red lights, and can drop the brake handle sooner than people can find drive when it turns green