The trouble with HV is that so many people wear it that it has almost become a cloak of invisibility.
In my former life as a Highways Engineer I'd have to do night time inspections (because motorists complain when you shut down the motorway in the daytime). We'd wear HV trousers with three, wide reflective bands on each leg, jackets/long sleeve vests/fleeces with similar bands around torso and arms and hard hats with reflective stripes and still cars and trucks would come close enough to kill.
We had a photo on the wall at our depot of an inspector wearing HV standing in front of an SUV covered in reflective panels - you couldn't see him - he was effectively camouflaged.
HV clothing WILL NOT SAVE YOUR LIFE. It may alert drivers of vehicles you are there but it may also give you a false sense of security. Be alert, keep scanning around you and remember drivers are easily distracted: the sun, the rain, the radio, the mobile they're not supposed to be using.
Take it if you wish but it's just another thing to carry.