Bumper numbers ... markings ID vehicles.
THE ANSWERS ARE FOUND IN TB 43-0209, TM 43-0139, AND AR 750-1. HERE ARE THE BASICS ...
TB 43-0209, Color, Marking, and Camouflage Painting of Military Vehicles, Construction Equipment and Materials Handling Equipment, standardizes how vehicle bumper numbers are applied.
The markings are divided into four positions in Para 9g-k. Positions 1 and 2 are applied on the left, while positions 3 and 4 are applied on the right. The positions identify:
1. the major command, organization, or activity the equipment is associated with
2. the intermediate organization or activity
3. the unit that operates and maintains the vehicle
4. the specific vehicle number (often associated with the order of march)
Anything beyond this policy, such as assigning a specific number against a specific unit position, is a matter of unit SOP.
TM 43-0139, Painting Instructions for Army Materiel, gives information about applying ID markings over camouflage CARC colors. Para 4-9 and Fig 4-2 tell you to use black lettering over brown or green CARC, green lettering over black CARC, and brown lettering over white or tan CARC. The lettering paint must be CARC if used on a CARC background.
Para 7-8c(16), AR 750-1, Army Materiel Maintenance Policy, allows MACOM commanders to conceal bumper numbers in tactical conditions. Para 7-8c(17) allows overseas commanders to comply with international agreements regarding vehicle bumper numbers. That's why some overseas commands paint solid light color rectangular boxes as the background for vehicle bumper numbers.
The TB and TM can be found online at LOGSA's ETM website:
AR 750-1 is available on the USAPD website at: