When did keyed ignition become common in cars?

I recently watched Bringing Up Baby with Katherine Hepburn and in she took whichever car she wished at any time. Clearly there were no keys back then.

When did keys become common?

Depends on the vehicle. I drove a 1913 Oldsmobile that required a key, my father’s 1928 Model T does not. Also, the definition of a keyed ignition can be defined differently. Most cars up into the 50’s the keyed switch just supplied the power to the ignition system, the act of starting the car was done pushing a starter switch. I had a 57 Buick in high school, the starter switch on it was under the gas pedal. Turn on the key and push the gas pedal all the way down to start the car. The movie you watched was from 1938, that was also a time when it was not unusual for folks to leave the key in the ignition of their vehicles. By 1938, most vehicles did have keys.

Top Gear did this a while ago while searching for the first “modern car” - ie. three pedals, gearshift in the middle, etc. You can see the full segment here.

The Cadillac 16 (1920ish) was the first car to come with a key. They didn’t cover what the first popular car to come with one was, although the Austin Seven was the first car to popularize the “modern” control layout, at least in Europe and Asia.

Was there a particular reason for people to do that then? Criminals and idiots presumably abounded then as much as they do now, and it’s not onerous to pocket an ignition key.

There were also “in between” keyed systems. I recall some models of cars in the 50s had keys, but could still be started without them. The switch had a “lock” position. If you turned the key to the lock position, and then pulled the key out, the ignition would be locked. If the key was taken out in the off position, it could still be started. The switch had wingnut-like flanges to allow one to turn it without the key.

So having a keyed ignition wasn’t the same as being unable to start a car.

For the same reason as many people didn’t lock their front doors back then. They didn’t see a need for it.

My mom’s 62 Chevy requires the key to start, but once the car is started, you can take the key out and do whatever you’d like with it whilst the car remains running. Mom loved to do that for us - a cheap, entertaining parlor trick.

I still can’t really believe that it works that way, but it does.

And it seems keyed ignition is becoming increasingly less common in cars - don’t a bunch of the higher-end, luxury vehicles now come with push button ignitions, only some of which require a key to be inserted first? (I know that that’s how the early Honda 2000s worked - you had to insert the key, then you push the Start button to start the car. I wouldn’t be surprised if newer models - and other newer cars - have gotten rid of the key altogether.)

My 09 Lincoln MKS has no key–just a fob you have to have in order to start the car. As long as you have the fob in your pocket or purse, you start the car by pushing a button. No fob=no start.

When did electric ignition come in? I remember some old cars in the 50s in the UK had to be hand cranked to start them.

See above - Cadillac 16. It was the first car to have an ignition key because it was the first car with an electric starter. Again, no idea when it became commonplace.

My 1989 Ford Escort did the same thing. I don’t know if it’s supposed to or not–my wife had almost the same car and it doesn’t work with hers.

People leave keys in movie cars for the same reason that they always find parking spaces right in front of the building they’re going to. It saves time and leaves out real-world fumbling and frustration (unless that happens - rarely - to be the point of the scene).

Most people today in movies don’t bother searching for keys. It’s only recently that actors started using seatbelts. And airbags never pop in car chase scenes that would normally be ended because of them. It’s not just that movies aren’t real. Every frame of every movie is false, no matter how realistic it might otherwise appear. Thousands of little movieisms make up the vocabulary of films, and we accept them because they speed the story along and that’s all we should really care about.

Little movieisms like car keys are different from big stupidities that we should care about, though. Speed the action but don’t insult our intelligence.

GM ignition keys of the 60s and 70s did that when the lock started to wear. Chrysler Keys did the same thing. I don’t think they were actually designed to work like that. Whatever keeps the key in the keyhole when the key is in the on position is weak and wears out really fast.

When I was growing up Dad never removed the keys from any car or truck when it was parked on the farm. When a car or truck was needed you did not have to look for the keys they were in the car. Car theft off private property was not as common as it is now. And no one just walked up to the farm house.

Around 1970 my brother who was living in the old house started pulling keys and installed a working lock on the house.

My 64 Olds allowed you to put the ignition in an “unlocked” mode, where you could start the car without a key, exactly like ftg explained. The car was t-boned a year ago and I can’t remember if you could take the key out while running…

Pre 1968 GM keys were designed to be able to be removed in the run position, and the ignition could be turned w/o key if left in the off position.
Only if the ignition was turned all the way to lock before removing the key was it necessary to use a key.

the wartime Jeep (the ‘real Jeep’, not the postwar pretenders which have usurped the name) had no ignition key, just turn the switch and press the starter pedal. Actually the very first ones did have a key but they soon dropped it.

don’t ALL military vehicles have no key?.

When I was in college (mid 90’s) my GF’s car was like that. (I think it was a Camaro or Trans Am, but it wasn’t that old. Maybe from the '80’s.) You could pull the key out, and as long as you didn’t turn the ignition switch all the way to the left (CC), you could shut it off without locking the ignition switch. That way the 2 of us could share the car with only 1 key. She just made sure not to turn the switch all the way to the left when shutting down the car, and I could come along later and start it up without a key and take off. (As long as nobody tried the door, and then tried the switch-sans-key, we were safe from theivery. We didn’t do this trick if the car was to be left alone for any amount of time. It was just a way to share the car when we had different class schedules.)

I still think having to put the key in the ignition (or the fob in a slot) is a good idea. It saves people from the problem of the key being in range, but not actually in the car. That’s great, until you get to wherever you’re going and can’t restart the car! Last week my buddy had to leave work to bring his wife her car keys. Her car had happily started up in the garage while her keyring was 10 feet away on the kitchen table.