Indian and Celtic (boadicea) legends talk of the use of war chariots. Egypt, Persia and perhaps China too used them. The romans had chariot races, but I hadn't heard of war chariots. When did chariots stop being used for warfare ? Why ?
(Yes, they were always a drawback in battles fought in rough terrain)
Later societies presumably had more roads and yet we hear of chariots being used primarily in more ancient times ?
Bonus: The word "car" apparently is derived from a word for "chariot", via latin.
When did chariots stop being used for warfare ? Why ?
Chariots were once the dominant "mobile" arm in many ancient armies because the breeds of horses at the time just weren't strong enough to be effective cavalry mounts. As breeding led to stronger horses, cavalry began to supplant chariots.
Chariots have several deficiencies when compared to cavalry:
Chariots are more difficult to control than individual horses. Scythed chariots in particular had a tendency to slice up the legs of friendly infantry. Cavalry can pull complex maneuvers that chariots simply can't, at least not easily.
If one of the horses pulling a chariot is incapacitated, the chariot becomes useless. As horses are big targets for infantry (especially archers), this is a significant vulnerability.
Cavalry is a more efficient use of horses. War chariots had to be pulled by more than one horse. As a result, an army can field more cavalry than chariots with the same amount of horses, or keep horses in reserve as spare mounts.
Horses are very good at crossing many type of terrain. Chariots are not, and chariots generally require quite a lot of open land to be used in battle effectively.
As for precisely when, I probably can't offer a fully informed answer to that question (especially considering that I'm not well-versed in Chinese military history, and the Chinese definitely were chariot users), so I too would look forward to seeing an answer to that question. Chariots were definitely in use well into the classical period, though, despite the fact that horses by that point could easily support cavalrymen. Julius Caesar mentions chariots being used by the Gauls Britons, for example. I can't really say when those disappeared out of common usage.
The last known use of chariots in battle was at the battle of Mons Graupius in Scotland, in AD 84 between the Romans and the native Caledonii (who used chariots).
It's clear the cavalry was superior to chariots in nearly every way, which makes is seem strange they were used at all.
The earliest record of cavalry was around 900BCE, which is well after records of huge chariot battles (eg, 5000 chariots at Battle of Kadesh between the Egyptians and the Hittites)
There is some speculation that the small horses of earlier times weren't strong enough to carry armed men for long periods of time. This theory is disputed, though.
Early horse saddles weren't as stable as later versions, and this may also have been a factor.