You can always take the "back door approach" and complain to the county Health Department. List the high accumulation of trash and garbage (Use the buzzword "uneaten food waste" and "possible human or animal waste"). List the high grass as a (Use the buzzword "haven for vermin and insects like roaches".). You may have even seen furry wild animals in that yard (Use the buzzword "rats" and "snakes".)
If you contact the Health Department and use these buzzwords the county WILL get involved and WILL at least pressure the occupants to clean up.
A call to the police (as another poster described) WILL result in attention being paid to the occupants with possible tender LEO love bestowed upon them for drug and alcohol activity. You might even mention the condition of any children living there, thus adding Child Services getting involved.
Don't forget top mention the constant round-the-clock traffic and activity.
A call to Code Enforcement/Building Inspections to maybe look at the condition of the dwelling for occupancy violations.
All this can be done annonymously and you can tell your neighbors to do the same without fear of reprisal.
E-Mail pictures to these agencies directly. Write your County Commissioners about this using all of the above buzzwords and itemizing the complaints. And let them know that there is NO action on this. I think you might then get some pleasant action. And don't forget to let your Commissioners know that your HOA has refused to act upon these problems. Also let them know about any agencies (police, Child Services, etc.) that have also refused to act upon these problems. Remind them that you and your neighbors VOTE and that you and your neighbors know OTHER VOTERS.
I can think a few crimes here ...
Disturbing the peace (noise, traffic)
Child endangerment (noise, traffic, sanitation, crowding, proper housing of children)
Public nuisance (noise, trash, traffic blocking access to your home)
MD Annotated Code violations (blocking access to your driveway/property access)
Various County& State Health Code violations (trash and waste accumulation, uncut grass/vegetation)
Housing Code violations (overcrowding, unsanitary living conditions, possible building code violations)
Truancy/Juvenile delinquency (are the school age kids even going to school or being supervised)
These along should give the police probable cause to enter the dwelling and at least make a cursory search that may turn up illegal drugs)