In Russia and Ukraine drivers don’t wear seatbelts. Same holds in many other developing countries.
Assuming cars are equipped with seatbelts (despite not being worn), and that most of the local drivers do not wear them, this scenario is actually ideal for the Western tourist.
You, the rational tourist, promptly buckles up in the taxi. In case there’s a crash, you’ll have some protection. The driver and other drivers, meanwhile, wear no seatbelt, thus reducing the Peltzman Effect which says people respond to safety regulations by acting more recklessly. Drivers who wear seatbelts drive less safely.
So the next time you get in a taxi and the driver says, "Don’t worry, we don’t wear seatbelts here," as the driver said to me in Odessa, Ukraine, just smile and say, "Good". And then buckle up.