This monstrosity disappeared off the Connect Tees Valley website for a while, but it appears it's made a comeback!
Aside from the fact it looks like it's been cobbled together in MS Paint, it doesn't actually tell the user much at all.
Bearing in mind the point of a transit map should be that it can be given to a person with no knowledge of the area and they can fathom out what goes where and where they can catch it.
The town centre is a mess, there's no way a person could reasonably work out what services are included in the technicolour loop. Then there's the colours themselves, I'm not sure of the reasoning the way services have been grouped. Some services which have widely varying destinations are shown as the same colour (X10, X17), yet some services which have similar routes & destinations are given unique colours (12, 13, 14).
The white circles are the most peculiar feature. I presume they represent bus stops, but only some are shown. Out of the ones that are shown, most are without labels, meaning they just sit around rather anonymously. There's no way a person could use the map to work out the departure location of their service. On saying that, maybe they're not actually bus stops, as the Newport Roundabout is reprinted as a single point, which suggests every service passing through calls at a single interchange point, including the ones whizzing overhead on the A66.
The rest of the resources provided by Connect Tees Valley are quite good, hopefully someone there can have a look at this one.