Most of us use some type of spotlight during patrol, either chrome or polished plastic. If you are in the driver’s seat, rotate the spotlight as far left as you can and twist it down. This will show the reflection of whatever angle you want.
If you are in the passenger seat, rotate the passenger side spotlight down and to the right. This acts like a convex mirror which gets rid of the blind spots.
The chrome verisions work best, but the polished plastic works great during the day, and only allows you to see the vehicles with their lights on at night.