I recently found out about the police ride-along thing, at first I thought it is some fiction in movies. Anyway, are tourists on B1/B2 visas allowed to take that dream ride?
If you check the programs listed in the other question regarding the ride-along
there is no restriction documented for foreigners to participate in a ride-along programs. However, it is more likely then not that you might be denied because, while I cannot say for sure about other departments, it is quite likely that you're a subject to the background check such as in the case of California State University, Fullerton or Howard County, MD Police Department.
So given that you don't have a US SSN and an associated driver's license it is more difficult to perform and thus more likely to be denied.
Probably not. Most police departments allow only local residents. Also, many of them will do a background check before allowing one in the police car. As you are a tourist, you are most likely to be denied. However, USA is an open country. When you are here, contact the local police office with a smile and good manner and they may let you ride along.