Some people are dismissive of this, implying that the AA is doing a publicity stunt that is really a form of blaming-the-victim. Not at all.
The AA is equally concerned about the safety of motorists. Look here, in the junction of Cheltenham Road and Arley Hill at 18:11 on a weekday evening. This van OU10FYG is stationary in the middle of the junction, held up by the vehicles in front; the cars coming up from Bath Buildings or Arley Hill are at risk of running into the van, given that they have both had green lights while this van is busy blocking the junction.
The hi-viz top the driver is wearing will reduce this risk, as it will be easier for cars crossing the junction to see the vehicle blocking the do-not-enter junction, so the driver will be safer. And presumably the AA's insurance costs will be reduced accordingly.