New Bedford RMV Service Center

My sixteen year old grandson applied for a learners permit test. Upon talking with the representative at the window we were told that a proof of guardianship was required before the process could be completed. A guardian or parent signature is the only Requirement on the application . Why is proof of guardianship required when you get there and not listed as a required documentation anywhere in the list of the approved documentation forms? I explained that I was the guardian but was told I had to show it proof. There is no requirement for this proof on any of the application process directions. Please let me know the results of this inquiry. Thank you

Very grateful for a patient examiner