How fast would a motorist have to be traveling for a yellow ( = 590.00 nm) traffic light to appear green ( = 550.00 nm)

How fast would a motorist have to be traveling for a yellow (λ = 590.00 nm) traffic light to appear green (λ = 550.00 nm) because of the Doppler shift? (nm is nanometer and is 10-9 meters)

(b) Should the motorist be traveling toward or away from the traffic light to see this effect?

(c) How fast would a motorist have to be traveling for a yellow (λ = 590.00 nm) traffic light to appear red (λ = 700.00 nm) because of the Doppler shift?