One of the big problems in any scientific measuring experiments are the effect of the observers on the behaviour of the system. In particle physics, the Heisenberg Problem surfaces -measuring something's mass slows it down; measuring something's velocity stops you weighing it. With humans, it is often the Hawthorn Effect: the act of being monitored changes people's behaviour. Either way: the observers get in the way. For this survey, the risk is that the survey cars will impinge on the flow of traffic, so altering the number, placement and velocity of the vehicles.
The survey team have anticipated this, and yet still managed to park their survey cars as close as they can to their deck chairs, by driving both their vehicles V127LEU and GK57YZS the wrong way down the Nine Tree Hill one-way section. They have not approached Stokes Croft at all, not even before the experiment began.
This leaves road unmodified; the bike lanes in Stokes Croft in their "raw" state, unobstructed by any more vehicles than normal.
Tax-dodging cyclists reading this blog may wish to save and print out a copy of the survey team and vehicles contraflowing the road and nipping up on the pavement. That way, when they are stopped by the police for illegally mimicing the same operation, they can declare that they are part of the Bristol Traffic survey team, and merely following the same scientific rigour when approaching the Stoke's Croft junction: to observe without interfering.