Exercise for the reader: Assuming average human eyesight, how many picoseconds away from a collision are you if you can read that size of text and the relative velocity between you and the car ahead of you is large enough that the red label is sufficiently blueshifted to look blue?

for 800nm to 400nm, we need gamma=2. So v~.86c. At 20m this gives you ~80ns.

For perspective, this speed is:

• 928 157 450 kilometers per hour
• 576 730 301 miles per hour

In one second, you would travel around:

• 258 000 kilometers
• 160 000 miles

Which is around 6.43 times around the Earth’s equator.