Some departments are using Chargers, but they've still got a long time to go before they've got the proven reliability that the Crown Vic has. It'll never be as cheap to buy, cheap to repair, and have the ease of maintenance that the Crown Vic has though.
Maybe in a few years if the Charger demonstrates that it can perform up to the standard of the Crown Vic (and not ignite when hit from behind) it will be a viable option for departments. For now, most will stick with what has worked well for them the past 25 years.
