Parking garages are the number one problem area for most of the residential developments that I consult for. Tailgating through the garage gate or overhead door is the biggest issue - it's almost impossible to stop people or other vehicles from entering the garage whenever a resident drives in or out.
We try to combat this through resident security awareness training ("please wait for gate to close before driving off") but this is never completely effective. Most developments have neither the space nor budget to implement interlocking gates (sally-ports), and the traffic volumes at peak hours would make this impractical at most developments anyway.
In some cases, we have recommended high-speed overhead doors (such as the Marathon) to replace slower doors or gates. This does seem to help to discourage tailgating. It's also easier to ask a resident to wait 6 seconds for a door to close before driving off than it is to ask them to wait 20 seconds.
At some developments, we have resorted to stationing a security guard at the gate and having them check parking permits as vehicles enter. This seems like a step backwards in terms of access control, but there are still many things a human can do more effectively than technology can.
Video can be a useful tool for investigating incidents after-the-fact, but does nothing to prevent problems from occurring in the first place. Also, many big-city police departments consider car prowls and other property crimes to be an extremely low priority - so much so that in some cases they ask the victim to file a report online and refuse to respond to the site. In most cases, these departments won't commit resources to investigating these types of crimes - even if a clear video recording of the suspect is available.
Unfortunately, the way that architects design many parking garages, once you are in the garage, you are in the building. If there are doors between the garage and the building, they can't be locked because they are required fire exits. But I'll save that rant for another day...
