Meaning you can choose between people driving to work with the sun up, or driving home from work with the sun up, but you can't have both. So I guess we'll just have to decide whether people would rather get hit by cars just after breakfast or just before dinner.
In the US, school generally school starts in the morning around the same time as or earlier than adult work time, so kids going to school are traveling at the same time as the work commute traffic.
The school day, though, is shorter than the work day so the kids come home while the adults are still at work, before the evening heavy traffic starts.
That introduces an asymmetry between the morning and evening work drives. The morning drive has a bunch of kids walking along the road. The evening drive does not.
This suggests that if you can only have one of those in daylight, it will probably be safer in the US to make that the morning one.
As they already do in many other places. Why should this be particularly dangerous for the UK compared to elsewhere?
Alternatively, some time zones are so wide that there's no argument that assumes a constant school or work start time and can also work with a standard time system. For example, not far east of where I live, it's possible to switch your clock from 8AM to 7AM just by driving to the next town over.
All of this by way of saying, presenting these sorts of observations as if they were compelling is specious. With the sole exception of the rate at which the planet is spinning, literally every variable is easy to vary.
