I thought we were talking about wide roads. Isn’t Railton narrow?
As a driver and ex-cyclist (cycling around London for 35 years) I definitely favour chicanes. I used to hate cycling over humps, having to stand up off the saddle at each hump. As a driver I hate humps - constant gear changing, potential suspension damage, and I know I am causing noise pollution and air pollution trying to keep to 20 MPH and slowing down for every hump and speeding back up.
A major factor is - which you will not know about if you don’t live next to a hump - when a heavy vehicle goes over a hump, there is vibration into nearby buildings.