**When were vehicles invented?**

Depends on how you define vehicles. Various sources place the origins of wagons with wheels and an axle back to 3000 BC.  The spoke-wheel horse drawn chariot dates back around 2000 BC. Hard to say exactly who to give the credit for the first vehicles.

**Why were vehicles invented?** 

It sure beats walking, and using horses you can move a lot faster than walking.

If you define vehicles as something moving not powered by an animal, the creation of steam powered locomotives started in the late 1700s. The first full-scale working railway steam locomotive was the Coalbrookdale Locomotive in 1802. Coalbrookdale is a village in the Ironbridge Gorge in Shropshire, England.

https://www.locos-in-profile.co.uk/Early_Locomotives/Early_1.html