Metallicar Syndrome

In Real Life, fugitives would most likely use inconspicuous-looking vehicles to travel around, otherwise, they'd get caught quite easily.

Not so in fiction.

If your protagonists, Alice and Bob, are of the Anti-Hero variety, they will drive a rare and/or unique-looking vehicle in order to show how utterly Badass they are. Somehow, the authorities never think to look for their pink-and-green SUV or purple-striped Ferrari, though ordinary Muggles might, if Alice and Bob are the We Help the Helpless type of anti-hero.

A subtrope of Cool Car and Unusually Uninteresting Sight. This trope is about how that kind of vehicle should be a liability precisely because it is so rare and/or unique, but somehow never is. A Cool Car can be cool and not fall under this trope (like Angel's Plymouth, for example)--keep that in mind before adding an example.

Named for the incredibly rare 1967 Chevy Impala (The Metallicar) that Sam and Dean Winchester drive on Supernatural; somehow, the authorities never mention their car when they send out alerts to catch them, even though this would help increase the possibility of capture because there are so few of that model left.

Examples of Metallicar Syndrome include:

Anime

Despite being an internationally-wanted criminal, Lupin III often drives the very rare Mercedes-Benz SSK.

Comic Books

Averted but discussed early in Runaways, where Chase drives the Runaways around and one of them complains about how uncool his plain white van is; he responds that he got it on purpose because a plain white van is the most inconspicuous vehicle possible.
The Batmobile is Awesome but Impractical: it gives away the fact that Batman (a hero who depends often on stealth) is in the neighborhood! Some versions have the ability to disguise their appearance as more normal cars, however.
- This one's something of an aversion as the Batmobile is supposed to be recognizable. Batman relies on fear as much or more than he does on stealth, and for a criminal in Gotham, knowing that Batman is in the neighborhood is about as terrifying as it gets.
Characters in Sin City are often supposed to be hiding out from the cops or mafia, but when they choose rides, they usually get the Cool Car. This trope is actually justified in that most cars in the city are vintage muscle cars.
Of course, we have The Green Hornet and his car Black Beauty. Not just a Cool Car, but one specifically modified to be distinctive. The 2011 movie even gives the Hornet multiple identical cars in case one is destroyed. Near the end of the film it demonstrates color-shifting paint (from black to red), but it's still not the kind of car you see every day.
The Scaremobile from Scare Tactics is a one-of-a-kind mobile home. It fits their cover as a rock band, but it is hardly inconspicuous.

Film

The red 1977 Pontiac Firebird Trans Am from Smokey and the Bandit.
- This is actually an aversion, as the entire point of The Bandit's car is to draw Smokey's attention away from the tractor-trailor he is escorting.
Black and white 1974 Dodge Monaco from The Blues Brothers.
Pretty much every car in The Gumball Rally.
Fozzie's Studebaker on The Muppet Movie is painted in psychedelic colors by the Electric Mayhem to help Kermit elude Doc Hopper. The paint job doesn't fool Hopper, but it does hide it surprisingly well when they stop in front of a similarly-painted billboard.
Played with in Cannonball Run, when a black Lamborghini tears past another competitor's car on its way to the finish line. The passed car's driver (Dean Martin) asks if it's in the race, and his co-driver (Sammy Davis Jr.) looks at him like he's an idiot before screaming for him to catch it.
Likewise in the sequel, where two hot chicks in a Lamborghini are practicing for the Run by messing with the local cops. They even invested in a false paint job: after getting the local cops all worked up looking for a speeding Lamborghini of one color, they drop by a friendly construction site and have the fake paint washed off. Presto, now there's a DIFFERENT speeding Lamborghini with two hot chicks in it tearing around the local cops!

"If I tell you boys something, you boys won't think I've been drinking, will you? The white Lamborghini has vanished...but there's a RED one behind me--correction, PASSING ME, and it's got two great looking chicks in it!"

Subverted to the point of comedy in Drive. The opening scene shows Ryan Gosling picking up a modified car for use in a heist. He and the mechanic walk past 5 or 6 flashy American muscle cars while the mechanic quips, "Here she is, plain-jane as can be, the most popular car in the state of California, the [modern day] Chevy Impala". Keep in mind that the Impala also used to be a flashy American muscle car back in the day.
Mentioned in The Dark Knight when Bruce needs to go rescue someone in daylight, and Alfred asks if he'll be taking the Batpod.

Bruce: In the middle of the day, Alfred? Not very subtle.
Alfred: The Lamborghini, then. (Bruce leaves) Much more subtle.

James Bond's Aston Martin DB5 could rotate the license plates to choose between 3 different versions to distract the villains. Even as the 1960s lacked computer databases of cars, even a thick-headed villain might have understood there couldn't have been too many silver Aston Martins in a given town, leave alone in the relative poverty of most European countries at that time.

Live-Action TV

The Impala, of course.
The A-Team's black van with custom red trim, though it got noticed as "The A-Team's Van" once or twice during the series. Not very often, though.
- Face Lampshaded this once when Hannibal told him to keep tailing the episode's villain in his white-with-red-stripes Corvette:

Face: He's going to know I've been following him in the 'Vette.

Referenced on The Muppet Show when Sam the Eagle complains that guest star Elton John "dresses like a stolen car."
Nash Bridges' Hemi Cuda (which there are like 7 in existence) He drives it everywhere even while undercover at times.
- Sure, but Nash is a cop. Who would he be hiding from?
  - From the criminals while working undercover?
Perhaps justified on Burn Notice. The team tends to use fancy cars for their high-speed chases and wealthy cover identities. But they also go through a lot of cars - stealing (and then returning) new ones for almost every job, and buying junkers when they are more appropriate. The exceptions include Michael's Charger, which really should have been recognized at some point. Of course, he blew it up, so that isn't going to happen.
- Most of the time Michael is not really hiding from anyone so there is no point in tracking him through his car. It is easier to just ask one of the many people who know where he lives.
In the Middle East Special of Top Gear, the hosts had to sneak across Syria. At first, they tried to modify their convertibles to more desert ready conditions. They painted their cars in various colors and added some accessories. When, they realize that it was too dangerous, they dressed up in burkas and drove down the roads. Their cars were still convertibles with crazy paint jobs and stuck out like sore thumbs.

Music

Aversion: 50 Cent - "Gotta Make It to Heaven"

In the hood they identify niggaz by they cars / So I switch off bass to stay off the radar

The Killjoys' Trans Am, or Dangercar

Video Games

Grand Theft Auto: Vice City: The assassin Lance Vance and his immaculate white Lamborghini. Granted, he's driving it around a town that is analogous to 1980s Miami, but it's still a bit flashy for a career criminal with a price on his head.
Covert Action has it mostly averted. In the driving minigame you have a choice of 4 cars with 4 properties — Tracking device (yes/no), Max. Speed, Handling (whether it can U-turn) and Conspicuousity. Usually your choices include a sport car or two with top Max. Speed, but the tradeoff is Conspicuousity "High" or "Extreme". Then if your suspect sees more than a few glimpses of such a car, you can easily lose the minigame by spooking (the suspect notices tail and leads you on the wild goose chase) and not only fail to find a new location, but raise the alert level for the rest of that mission, making it harder and possibly have adversaries go into hiding.