If you want to confuse a teenager today, really take them out of their element, you could do worse than to plop him or her in a 1970 Chevelle or a vintage Lincoln Town Car.

Looking around at the ashtrays, crank windows and manual locks, sitting in what could have been their grandfather's car, they might as well be in another world.

Car design changes quickly, and features that were once standard in just about every car on the road have mostly gone the way of the dinosaur.

Ashtrays

The move to ashtray-free cars began at Chrysler, whose 1995 Cirrus and Dodge Stratus sedans were the first to be sold without ashtrays as standard equipment. Today, you're much more likely to find a power outlet for a cell phone or MP3 player where the push-in lighter once was, and ashtrays have mostly been replaced by cup holders and storage compartments.

Not only is it a question of an anti-smoking movement, but also of space. According to the United Health Foundation, about 20.8 percent of the population smokes, which means about 60 million people. According to Apple, more than 100 million people have bought iPods. When you add in iPhones, Blackberrys and various other cell phones, it's clear the smokers are simply outnumbered.

But they aren't totally extinct. For $15 to $100, car buyers can get a smokers group option that includes ashtrays and cigarette lighters. Plus, some luxury automakers such as Rolls Royce still include ashtrays for their humidor-owning customers.

Bench Seats

If you're in the market for a pickup truck, you'll easily be able to find one with front bench seats. But if you want a car with that once-common feature, good luck.

While big cars were once renowned for their ability carry six people -- more if you didn't mind a little squishing -- the number of cars with front bench seats that can accommodate three riders has declined over the years.

A few years back, Toyota dropped the bench seat from its Avalon because 92 percent of buyers were choosing the models with bucket seats.

These days, only about a half-dozen American-branded autos in the full-size class offer six-passenger seating, including the Buick Lucerne, Cadillac DTS, Mercury Grand Marquis and Lincoln Town Car.

Window Cranks

If you want to confuse a child, put him in a car with a crank window. Most kids these days have never seen anything but power windows and wouldn't know what to do with a crank handle.

In 2006, Honda became the first of the large automakers to banish the crank window, moving entirely to power windows as standard equipment.

However, with the demand for affordable cars rising, some automakers are paying attention. The lower-priced Chevy Cobalt LS and Toyota Corolla are some of the few cars these days to feature the hand-crank standard. While power windows are available as an option on the Corolla, Cobalt owners don't get that choice.

And India's Tata Nano, proclaimed by its makers as the world's cheapest car, goes on sale this spring with a price tag of just over $2,000 and crank windows.

Cassette Decks

You could argue that the CD player could just as likely belong on this list. With the popularity of MP3 players and satellite radio, CDs are fading and cassette decks are all put a distant memory.

Some automakers, such as Lexus, still offer vehicles with cassette decks, but more and more are focusing on new technology. According to the market research firm iSuppli, USB ports are available on 25 percent of all 2009 vehicles, up from 12 percent in 2008, and iPod interfaces are now on a full third of all 2009 models.

Apple, meanwhile, claims that around 80 percent of cars have iPod compatibility, although the company includes even simple line-in jacks that work with everything from iPods to old Walkman cassette players.

Manual Locks

Today's drivers have become so reliant on power everything that a Florida woman recently called 911 because she was stuck inside her powerless car unable to figure out how to unlock the doors.

The fact is the days of the old manual "pull-up" locks are just about gone. In a time where many people don't even use a key to enter or start their cars, the manual lock is just about extinct.

Again, like the crank windows, the manual lock seems to have found a final holdout in economy models, as some automakers seek to limit auto features to only the most essential items in their cheapest models. The Corolla and Cobalt LS both feature manual locks standard and the sub-$13,000 stickered base models of the Nissan Versa, Kia Rio and Hyundai Accent are without power locks as well.

Still, today's driver has likely forgotten entirely, if they ever knew, what it was like to have to stretch across into the backseat to unlock the rear passenger side door.