London’s Cycle Superhighways (CSHs) offer one example of a reallocation of road space between cycles and cars. The graphs above and below indicate the impact on journey times for motorised traffic, as of November 2017. These are from Transport for London.
Journey times are certainly up. But for the first time, they are actually falling. This reflects in part traffic evaporation as commuters switch to other modes.
And keep in mind the overall increase in *people* being moved along these routes:
Recent monitoring data shows that central London segregated cycle lanes are moving five times more people per square metre than the main carriageway
– Transport for London, FOI request response