Perhaps because of the heat, Phnom Penh is more laid back than other Asian megalopolises. People are friendly, especially taxi drivers, who know just enough English to demand that they stick with you all day and become your personal tour guide. Say no, and their moods darken. Suddenly, going anywhere becomes impossible. An alternative: Transportation is so cheap in Cambodia that you may as well just get a credible driver for the full day. Taxi Vantha, costs just $25 per day, and is well worth it to make the most of your business trip or tourism time. A ride to the airport when you leave: just $7.

It's pandemonium as taxis compete for precious pavement with tuk-tuks, buses, bicycles, rickshaws, trucks, pedestrians, camels and the occasional elephant. You'll watch in awe as traffic utterly disregards traffic signals and centerlines while your ears are assaulted by Hindi pop music whose pounding beat can't mask drivers' apparently mandatory use of the horn for echolocation. You won't be involved in a serious accident, however, since you'll never exceed 15 mph while you navigate through the choking smog.

An alternative: Call Cool Cabs. They cost 40 percent more than regular taxis, but that's still not much, and you're guaranteed to get air conditioning, an absolute must.

Jakarta is another chaotic Asian mega-city with 24-hour traffic trouble and the only place where we've heard of taxi muggings in which the driver reclines his seat to pin your legs while his accomplice jumps in, knife in hand, to conduct a full-body search for money belts and hidden cash. It's a creative but chilling technique. An alternative: Call the Blue Bird Group. It's the biggest and best-known taxi fleet in town.

For more information: Blue Bird Group

Although there are 14,000 yellow taxis on the clogged streets of Athens, flagging one down isn't necessarily easy. Drivers (the vast majority of whom are smokers)--may or may not stop for you. It depends on whether you clearly shout your destination at them and if they feel like heading in that direction. Once in the cab, prepare to be joined by other riders going your way, watch out for circuitous routes and don't expect to get a receipt without a struggle. As one Athens travel guide puts it, "One could say the Athens taxis have their own set of rules, which aren't always legal."

An alternative: Book in advance with English-speaking, non-smoking "George the Famous Taxi Driver of Greece" or his son Dennis, "Son of Greek Taxi," for airport pickups or day tours.

For more information: Taxi Driver of Greece

The news out of KL isn't good. In September, 2008, Agence France-Presse reported that a Malaysian survey of 200 foreigners from 30 countries found Malaysia to be the worst among 23 countries in terms of taxi quality, courtesy, availability and expertise. Respondents called the fleet "a source of national shame" and "a serious threat to tourists--rude bullies and extortionists." What's the problem? As one local said, "Taxi operators and the companies which hold the licenses are all linked to some politician or another. Drivers here are ruthless because they are unchecked by authorities, who are almost non-existent." While travelers can be expected to cope with broken meters and unscrupulous touts, asking them to deal with a corrupt local government propping up the whole system is a bit much.

An alternative: Book in advance with Sunlight Radio Taxi.

For more information: Sunlight Radio Taxi

While a New York taxi ride can be quite a thrill, it can also be quite a slog. For example, the Big Apple is famously unfriendly to travelers arriving by air. Rail travel to and from the city to JFK Airport is possible but grueling, and that leaves the taxi option, which puts you on the notorious Van Wyck Expressway, a six-mile stretch of nightmarish congestion that will cause agita whether you're heading to JFK or trying to get out of it. Luckily, it's a flat $45 fare, so no matter how long you sit—and sit you will—you won't pay more.

An alternative: Make the trip by helicopter in 8 minutes for $140 with US Helicopter

For more information: US Helicopter

Those green-and-white VW Beetles may be among the world's cutest taxis, but sad to say, Mexico City is home of the "express kidnapping," during which your taxi-driving thief will take you to an ATM, rough you up and force you to withdraw money. The problem is so well known that the Department of State maintains a travel warning about it.

An alternative: Only take taxis that you've contacted in advance or that you hail at a regulated taxi stand, called a "sitio."

Visitors to Nigeria often end up exasperated by a culture of bribery, extortion and petty graft that can make even the simplest itinerary a challenge. Ominous-looking roadblocks can pop up anywhere and anytime in this kleptocratic environment, and it may take a small bundle of cash to get through. Yellow Lagos taxis are cheap and plentiful, but proceed at your own risk.

An alternative: Work with your hotel concierge to find private transportation and stress-free routes.

The problem in Bangkok isn't with its colorful fleet of air-conditioned taxis and friendly drivers. The problem is how many of them there are, not to mention all the other cars, trucks and buses clogging the narrow streets. Add the iconic three-wheeled tuk-tuks darting around all the other vehicles, and you have traffic chaos that will require true Buddhist detachment to endure.

An alternative: Take to the water. Do your northbound and southbound traveling in a hired boat on the Chao Praya River. It's fast, scenic and not outrageously expensive. You can also try the Bangkok Skytrain, but its routes don't lend themselves to tourism.

The new Russia's anything-goes form of capitalism carries right over into the world of taxis. Indeed, anything goes, and anyone will pick you up if you stick out your hand. You'll see plenty of metered yellow taxis, but you'll also attract gypsy cabs, ordinary Muscovites who are simply looking to make a few extra rubles as they drive across town. If you don't speak Russian, you may find it hard to haggle and could end up getting into an incomprehensible shouting match.

An alternative: Book for your trip in advance online at sites like Way to Russia, which offers services around $16 per hour, or www.limos.ru, which can provide a Czar-like ride in a Hummer.

For more information: Way to Russia

A megalopolis of nearly 30 million people (and growing), this Brazilian behemoth can be nearly impossible to get around at times of peak traffic congestion. Think of Los Angeles, only three times as crowded. The city's white taxis are plentiful and efficient, but given the distances and the traffic, you could be in for a very long ride. Plan in advance for off-peak trips with Rádio Táxi Vermelho e Branco.

An alternative: Do what the rich locals do, and stay above it all by taking to the air. São Paulo has helicopters and helipads galore, making it possible to hopscotch from airport to hotel to meeting without ever setting foot on the street. Investigate the high life with ATM Helicopteros.

For more information: ATM Helicoptero

In a city full of fanciful transportation alternatives—everything from rickshaws to wildly decorated jeepneys—the local white taxis appear boring by comparison. What won't be boring is the fight you have with the driver when he refuses to turn on the meter and instead tries to haggle for an unfair flat fee. Ask that he turn on the meter before you close the door and sit down. If he won't, simply flag down another taxi and try again.

An alternative: Hire a private car (as low as $20 per day), or try the reputable Avis Taxi, which comes when you call and adds about 70 cents to the meter for the pick-up.