Guam Metas

If you look at the rear-left of the Guam car (right-side on the above picture), you will see a tiny bit of a bar sticking out- this distinguishes Guam from the Northern Mariana Islands.

Google Car

Guam uses these blue highway shields that helpfully say ‘Guam’.

Street Sign

Guam has these large octagonal, concrete utility poles, in contrast to the Northern Mariana Islands which generally has wooden utility poles.

Poles