You're driving along at the normal legal speed -- at least 10 mph over the official speed limit -- and suddenly you feel a touch moist above your t-shirt.
You look in your rear-view mirror and there are flashing blue lights. However, these lights seem to be perched on a slightly smaller version of a Formula One race car.
You're sure you haven't been at the pot brownies, nor have you had more than a half glass of questionable sauvignon blanc.
It is then that you remember you're in the area of England ruled by the Avon and Somerset Police.
This is the police force that has decided to employ an Ariel Atom in order to combat speeding drivers and motorcyclists.
It so happens that the Ariel company is based in the Somerset region. It only has seven employees. The Atom was recently described by Top Gear's Jeremy Clarkson as "one of the most beautiful cars in the world."
That may, indeed, be the first impression of local drivers shortly before a police officer jumps out of the Atom to offer them a beautiful, speedy ticket.
As the Telegraph reports, the Atom is thought to be the fastest police car in the world. Given that it goes from 0-60mph in 2.5 seconds, it surely has a chance to deserve that honor.
The car itself costs 38,000 British pounds (around $64,000), and the police haven't bought it on a permanent basis. They've merely borrowed it for the summer to deter the negligent in a road safety campaign.
Ariel's director, Simon Saunders, told the Telegraph: "The Atom is designed to be driven to a racetrack, where you can drive to your limits in safety and in a professional environment designed for the purpose. The road really isn't the place to explore your or your vehicle's limits."
Unless, of course, it's in the hands of a trusty police officer, speeding to catch a banker going 110 mph in the outside lane.
One might imagine, though, that if the Atom ever hit the roads, it would cause its own traffic problems.
Drivers would slow down, just to stare at its fetching features. They would rubberneck so much that the police officer would have to accelerate away from them, hence breaking the speed limit himself.
There again, I see police cars speeding down the freeway all the time. I suspect, though, that the only thing they're chasing is the fast food at Wendy's.