You must: (a) dim your high beams for oncoming vehicles by the time they are within feet of your vehicle, and (b) dim your high beams when the vehicle you are following is within feet.

500,300

Explanation:

Safety measures on the road can be regarded as activities and precautions that should be taken in order to improve safety on the road which means to reduce risk.

Whenever one is driving with high-beam lights on, one of safety precautions that must taken into consideration is that ;

You must: (a) dim your high beams for oncoming vehicles by the time they are within 500 feet of your vehicle

(b) dim your high beams when the vehicle you are following is within 300 feet.

When you dim the beam, the oncoming vehicle won't be blind, he/she would be able to see clearly. As you are approaching a car with high-beams, look at the right edge of your own lane and use Conner of your eyes to watch the oncoming car to avoid been blind .

divide the right side by the left side

0.024÷1.2=0.02 for example

the doppler effect is used by weather forecasters to measure 

moving clouds