Baltimore began installing speed cameras in fiscal 2010, and it has steadily increased the number it employs since then, from 28 initially to 83 today. The fact that total speed camera revenues have increased during that time, then, is no surprise. But revenue for the fiscal year that ended in June exceeded expectations by $4 million. The figure would have been higher if not for more than 3,000 tickets that were thrown out because of an error in their processing. In all, the city collected more than twice as much for its speed cameras as the state did from those posted in highway construction zones across Maryland.