Studies have shown that wearing hi-viz colours, particularly on moving extremities such as one's feet
I have a better idea. Let's move the hi-viz colours from the feet to the pedals, so that you don't need to choose your clothes based on having hi-viz colours. Let's also make the hi-viz colours retroreflective, i.e. all of the light shining on them is reflected to the exactly same direction, no matter where the light is coming from.
What you get is pedal reflectors.
Flashing lights, also dramatically increase the chances of being seen by the driver of an approaching vehicle.
Let's make a thought experiment.
What if every car on the road would have a flashing headlight?
I think you'll realize that the idea is not good.
Does having a bicycle frame in a bright colour also dramatically reduce the probability of being hit by a vehicle?
A typical bicycle frame main tube is perhaps 30mm diameter and 55cm length. There are three such tubes. Their total area is 0.05 square meters per side thus.
A typical bicycle chainstay/seatstay tube is perhaps 10mm diameter and 50cm length. There are four such tubes. Their total area is 0.02 square meters per side thus.
You get 0.07 square meters of surface per side.
Now, a problem is that a car approaching a bicycle is commonly seeing the bicycle at a small angle, let's say 5 degrees. This means the effective area is not 0.07 square meters but rather 0.07 * sin(5*pi/180) square meters or 0.006 square meters.
A frame will reflect perhaps 5% of the light back to the direction where it came from. The rest is scattered to other directions. So if this is the case, a frame corresponds to a 3 square centimeter retroreflector.
One of my rear retroreflectors is 4 cm x 4 cm, i.e. 16 square centimeters. I have two such retroreflectors for a 32 square centimeter total area.
The two retroreflectors alone are therefore 10x more efficient than frame color.
My cycling jacket is about 40 cm x 50 cm when seen from the rear. It is seen directly from behind, so a small angle does not decrease its effective size. It is 2000 square centimetres. If it reflects 5% of the light back to where it came from, it is equal to 100 square centimeter retroreflector. This is 3x more than the retroreflectors I have on my bike.
Your idea is worthless. Bicycle frame tubes are so small and seen at such an angle that they don't contribute to visibility.
What contributes are, from most important to least important:
- Cycling jacket being of bright color