As a kid I've traveled in such tangas from Dharwad Railway Station to my grandparents home. The ride was slow but interesting especially sitting next to the driver in the front seat.
Dipi and I in the front. Mom and Grandfather would be sitting at the back. Those days Dharwad used to be peaceful, hardly any traffic, no rickshaws on the roads, mostly pedestrians, bicycles and tangas.
Babu told me that just six or seven of these plying at the moment. Looking at it it reminds me of Basanti's tanga in Sholay.
I've seen tangas in Badhravathi and Bangalore also but the design is different... some what similar to a bullock cart with a top.