You have probably already noticed lots of different marked cars on the road, but even more, new models, are available for unmarked options. What do look for when blue lights appear in your rear view mirror, these days?

With a style that had not changed in more than a decade, the granddaddy of police cars, the ubiquitous Crown Victoria, is retiring. "I only remember a small portion of my career where we didn't have Crown Vic's," said Chattanooga Police Sgt. Craig Joel. Ford stopped producing them in 2011.

What will replace the sedan synonymous with law enforcement? There are many alternatives on the road, right now: the re launched Chevy Caprice, the muscular Dodge Charger, the Chattanooga-made Volkswagen Passat has even been re-purposed for patrol. Chattanooga has chosen the Ford Taurus.

As the old cruisers age out, you will see more of Taurus Police Interceptor model proudly wearing the new CPD color scheme. How are they different? For one thing, back seat 'guests' will notice less space. But, perhaps the biggest change is the fact that the Taurus is front-wheel drive. "The way you handle, the way you brake, the way you accelerate, the way you curve, everything is different on these cars," Sgt. Joel explained, "to the point where it's actually required some remedial training for several departments across the nation."

It may be thought that traditional rear-wheel drive models like the Crown Victoria are faster off the line, but Sgt. Joel explains the Taurus fits well into CPD's relatively new philosophy. "We're not so much in the chasing business as we are in the performance business," he said. "We're more focused on getting there to provide those services than chasing folks around."

Perhaps the most important factor in choosing that car or many of the other options available today, though, is health of the officer. "The new police interceptor vehicles are much safer vehicles, today," said David Wright of Mountain View Emergency Vehicle Service. There they take blank slates and turn them into crime fighting machines, installing everything from cages to lights and radios to laptop computers. "All they need when they leave here is an officer and weapons," he added, and then they can do their jobs."

Wright says, even though they may look like regular cars or SUVs, "It's not your typical vehicle that's behind you anymore." That is 'vehicle,' not 'car,' because there are plenty of options. He showed us an all-wheel drive SUV that will soon become the norm for the Tennessee Highway Patrol and, eventually the CPD. "You're gonna have vehicles that will be more suited for K-9 usage. You're gonna have investigative usage , patrol usage, so you'll see different usages and different types of vehicles used for many years," Wright added. "Anything underneath the top of this car is purpose-built for a police vehicle. From the breaking system to the suspension system, the torsion system underneath this car, it's purpose-built to be a police vehicle."

The Crown Vic still dominates the lot at Chattanooga's Police Services building, but already there are the Taurus, the Ford Fusion for Detectives, the Ford Focus for Parking Enforcement and others. How are drivers supposed to know who is pulling up behind them? "If it's a marked car," Sgt. Joel explained, "it's gonna look like you're being attacked by a space ship with a lot of blue and white lights in the city."

If it is unmarked, it is okay to wonder. "If you see something with just one small dash light," he continued, "it doesn't mean it's not an officer. But, if you are not confident, you have every right to slowly, carefully, indicate you've recognized him, tap on your brake, put a turn signal on, but wait until you're at a more public area."

Once you have pulled over, it is good practice keep both hands in view on the wheel. "Know that it's gonna change the encounter," said Joel. "That officer is not gonna be sure if you're fleeing or not and the tension's going to go up."