If it really was trespassers throwing a brick at the cab, they really do need to use the full force of the law. That is literally putting the drivers' life at risk, with the potential for something far more horrendous.
Big IF at the moment.
There is no punishment that can actually be administered which is actually effective against certain individuals, unfortunately. The sort of individuals who carry out such acts won't be bothered with any punishment that could actually be issued.
If it's kids involved, the police seem keen to avoid criminal convictions (for example, near me recently, a brown belt in martial arts did a premeditated vicious attack against a kid on their way to school, and was just given some sort of caution, and the school was only able to suspend them for a few days, despite clear video footage of the incident being available).