The W110's rising vertical speedometer is a beloved signature, likened to a barber pole or thermometer, and one commenter who works for NHTSA claims the design was studied and found to reduce average driver speed. Buyers do watch for it displaying correctly, with color stripes expected to rise with speed.
The vertical 'thermometer' / barometric speedometer
Mercedes-Benz 190/200/230 Fintail (W110) · cosmetic