The Chevrolet Impala Police Package is available in both "marked patrol" (9C1) and "undercover" (9C3) variants. With extensive reinforcements to a base model Impala, both models include special features not found on civilian vehicles. In 2005, both models were powered by a special Chevrolet 3.8-liter V-6 with a top speed fuel cut-off at 124 to 129 mph.
Apart from the roof, all exterior body panels on 2005 police Impalas are two-sided galvanized steel. A special single key locking mechanism operates all locks, with an option for single key fleet management. Other unique exterior features include non-removable integrated body molding and a special high speed anti-lift windshield wiper system on the driver's side.
Heavy-duty front bucket seats with integrated security panels come standard on all models. The center console has been removed. Improved interior lighting provides sustained illumination and auxiliary functionality; all glass is deeply tinted. Rear doors and windows are equipped with lock-out switches, and high strength floor coverings replace original equipment.
The entire electrical system has been improved on all 2005 police Impalas. A reinforced engine cradle, heavy-duty transmission, a specially calibrated ABS braking system and battery rundown protection are standard. With a stainless steel exhaust system, the entire chassis is "lubed-for-life." Police packages also include a starter interrupt and lockout protection, along with a unique "surveillance switch" that disables all interior and exterior lights when engaged.
As of 2010, the Impala police package includes structural improvements, a tunnel crush box and a new flex-fuel 3.9-liter V-6 engine. According to Chevrolet, the 2010/2011 Impala received five stars, "the highest possible frontal crash test rating (driver and front passenger)," from the National Highway Traffic Safety Administration.