Has anyone seen any vehicles on the road, with steady turn signal indicators?

I was behind a 1990s Buick Regal sedan recently, and the driver put on the turn signal lamp to turn off highway, and it just stayed steady yellow light.

I had also seen similar, several years ago when I saw an old Oldsmobile sedan, of 1980s signal merge onto the highway, also with steady yellow signal.

I’m guessing in both cases, having weak flashers, that don’t have enough resistance to flash the bulbs. I haven’t noticed this on newer cars, that probably have the module style turn signals.

Although, I have also seen some vehicles with turn signals that flash very slowly, or quickly, often with those silly looking aftermarket LED signals.

I would guess with steady turn signal, that there would be no audible click from the flasher at all, and steady green arrow indicator on dashboard?

Looks like failure of the turning signal timer. This shouldn't be happen.

To me it looks like blown out flasher, could be an aftermath of some short circuit frying the hysteresis coil in the flasher.
Old thermoelectric flashers use the passing current through a small electromagnet coil to form the hysteresis, so the lower current from a burned out bulb would lead to faster flashing.
When overloaded, this coiltends to fry into a short circuit, leading to no hysteresis at all, so the contacts are then just arcing, until they weld closed.

Or it could be really very low current, so the user must have replaced all lamps for very low current LED ones, so the low current passing through the heater "muscle" wire (parallel to the contact) was unable to warm it enough for the cobtact to close. And it created so low voltage drop across that heater, so the lamps light permanently.

On a lot of older American cars, the signal would burn steady if one of the bulbs was blown. Same if a bulb was replaced with an LED. Not enough amperage for the flasher to work.
On other cars they flash very fast, depends on the type of flasher.

Oh yes, I had heard about that behavior when a bulb was blown, I had forgotten about that.

Yes, it can be caused by a bad flasher, or if the owner installs low current LED bulbs they may flash very fast (hyperflash) or not at all. Like Medved said, old flashers are usually a thermoelectric relay type thing that plugs into a socket in the fuse box. That's why they clicked while flashing. (It didn't used to be just a sound effect like I guess it is now.)

Old flasher circuits were meant to be used with incandescent lamps. LED retrofits did not pull high current, so the flasher didn't work.

Yep!

Our 1981 Honda Accord would behave this way if a turn bulb was blown, the indicator would just stay on constantly. This is the only car I've ever seen that did that; all others have the indicator flash at double speed if a bulb is blown.

 Electronic flashers usually hyper-flash while the mechanical versions just steady burn . Another thing that will cause either hyper-flash or failure to flash is a bad ground to the lamp . My brother's Honda SUV had a bad ground to the left headlight ass'y causing the front signal lamp to light dimly causing hyper flash .