So why did the Lubbock Police Department buy sexy new Mustangs for Night Patrols? According to the Lubbock Avalanche-Journal, it's to keep motorcycle cops safe:

The cars will be out during the night, and the patrol units will not have to take the training required by motorcycle officers. Stevens said motorcycle units enforce traffic during the day.

This helps in two ways: officers without motorcycle training can take night shifts, and taking motorcycles off the streets at night minimizes the danger for those officers. I've personally lost friends to night-time motorcycle accidents because it's just more likely drunk people will be out at those times.

Regardless of what time it is, always double check for motorcyclists, especially in the summer!