Some notes on technology.

I'm used to technology levels in GURPS, which are a bit different to those in Traveller, so I've clarified things here for my own use, for what a typical culture of a given tech level would be like.

Note that I assume that a Tech Level is pretty much what a world can produce or at least maintain itself, not necessarily what is available. A world on a major trade route will tend to have easy access to whatever technology is available on neighbouring worlds, at least for small scale commercial items.

TL 0-2 are pre-industrial revolution. The only technology available will be what comes in from outside.

Civilisation will be tribal, warring kingdoms and the start of massive urbanisation.

Industrial revolution, 19th century Earth. Horse and steam power.

Mechanisation and basic chemistry and medicine, early 20th century. Basic cars, common (but expensive) international travel, air craft and big cities. Telecommunications will be widespread, but not ubiquitous.

Nuclear power, early mechanical computers. Big cities and common air and sea travel. 1950s Earth.

Basic computer technology, heavy urbanisation and the growth of cities. Late 20th century Earth.

Early 21st century Earth. Mobile communications are ubiquitous, air travel is cheap. Glass and concrete cities.

Beginning of interplanetary travel with gravitics, industry beginning to move into orbit.

Cities are very much like early 21st century, but air cars are beginning to become available, with affordable space travel. Colonisation of asteroid belts and other worlds greatly expands access to resources.