Stepping into oncoming traffic to wave at speeding sedans is a dubious, if not outright dumb, way to hail a cab. Designers are on the case.

A project sponsored by the New York advocacy group Design Trust for Public Space in partnership with Parsons the New School for Design has engaged a dozen designers in a rethink of the urban taxi system, from vehicles to traffic flow to -- Washington, please note -- civic image as conveyed by a visitor's initial ride.

Designers brainstormed with drivers, fleet owners and regulatory officials. Their focus was New York's canary yellow armada. But making taxis safer, more enjoyable and less polluting makes sense wherever cabbies troll for fares.

Proposals went on view at Parsons last week, and will remain through Jan. 15. A bright yellow booklet called "Designing the Taxi" presents evidence that annoying little aspects of taxi travel -- like making change in the dark -- need not be tolerated. As for flagging a ride in the fast lane, why not link up cabs with the digital revolution so hopeful passengers can text-message drivers from a safe spot on the sidewalk?

All that's missing is the collective will to innovate, says Masamichi Udagawa of Antenna Design. And to figure out who would foot the bill.

The designers began with a basic premise that "a taxi is not a car," as Parsons Dean Paul Goldberger writes in the book. Unlike sedans, which were created to transport families long distances in comfort, city cabs make short runs, often with single fares entering and exiting rapidly while toting awkward luggage. "It may have four wheels and carry passengers, but the circumstances are completely different," Goldberger says.

Futuristic concepts would diversify the fleet. A novel MiniModal with hybrid engine and raised glass roof would be equipped with double doors and a sliding ramp for wheelchair access. An extra-tall CABsule, with maximum speed of 50 mph, would transport standing passengers, as well as seated riders, and have space for a wheelchair. The driver would sit in a "super-comfortable cockpit with great sight lines," according to designer Harris Silver of CityStreets. The entire cab would glow when vacant.

Taxi nirvana would be fashionable. Ayse Birsel and Bibi Seck fantasize about drivers dressed in Calvin Klein T-shirts, sitting on Aeron-like mesh seats and clinging to Nike-designed ergonomic "12-hour" steering wheels. Birsel and Seck also contributed an ingenious common-sense design for retractable child seats.

Expanding the cashless payment system to accept transit cards as well as credit cards is a brilliant idea that would distinguish a progressive metropolis from the rest.

Antenna Design, which has redesigned subway cars for the New York Transit Authority and is creating a security kiosk for station platforms, dreamed up a passenger console for cabs with GPS navigation map, temperature and radio controls, a tip calculator, credit-card slot, cup holder and Wi-Fi connection.

"It's all possible," says Udagawa. "These are all available technologies."

The console was designed to retrofit vehicles such as the Ford Crown Victorias that make up 92 percent of New York's fleet. (Six hybrid Ford Escapes were added to the 12,000-vehicle fleet recently.) After three years on the road, New York cabs aredecommissioned and sold to other markets, which explains why so many of the sturdy but bland sedans are cruising District streets.

As a National Design Awards finalist in 2003, Udagawa traveled to Washington for lunch at the White House. He still recalls hopping off the spiffy Acela fast train and into a D.C. cab.

"I wasn't too impressed," he says.

Silver-gray Washington Flyers whisk Dulles arrivals into the District. From there, it's a free-for-all of 80-plus companies and independent drivers in vehicles of varying ages and conditions. Air conditioning is a recent innovation. They could all benefit from Fox & Fowle's proposal to turn cabs into "roving air filters" that collect particulates.

A visit to the Diamond lot on Rhode Island Avenue NW revealed several aging Ford Crown Victorias, a Ford Police Interceptor and a Chevy Caprice Classic wagon.

Driver Ted Tennien was just starting his day in a Mercury Grand Marquis customized with a padded steering wheel, trash bag on the driver's door, blue-and-white Playmate mini-cooler and signs advising "No Smoking Don't Slam the Door." A metal bar, which Tennien referred to as a "shoehorn," was stashed within reach "to help change my tire." He had installed "Call 911" lights on the roof.

"That doesn't work," said Herbie Best, another Diamond driver.

But the light is cheaper than a partition or the digital camera Best installed in his Lincoln. It's not OnStar. Images go only as far as the car trunk.

Best dreams of a fold-down ramp for wheelchair accessibility. He imagines the back seat folding away into the trunk to "let the passenger wheel around." Drivers would no longer have to lift anyone onto the seat, or heave a wheelchair into the trunk.

Taxicab innovations have not come easily. In 1976, the Museum of Modern Art's design curator, Emilio Ambasz, tried to spark interest in a new urban cab through an initiative called the Taxi Project. American car companies declined to participate, as Goldberger recalled in his column for Metropolis magazine. Volvo, Volkswagen and Alfa Romeo jumped at the chance. But it took federal subsidies to persuade the American Machine and Foundry, and Steam Power Systems to produce prototypes.

In the end, five model cabs were exhibited in the sculpture garden and quickly forgotten. Deborah Marton, executive director of the design trust, pointed out this week that they foreshadowed the minivan.

Marton has moved on to Phase 2. The Crown Victoria's days are numbered as an urban people mover, she believes. "It has come to the limits of its flexibility to be upgraded," she says, "and it's a gas guzzler. There's no reason that vehicles on the road 24/7 should be polluters."

She hopes to develop a modern taxi prototype for display at the New York International Automobile Show in 2007, which is the centennial of gasoline-powered taxis in New York. (The first, a Daimler Victoria, was invented in 1897 and put to work in Stuttgart, Germany. New York got them in 1907.)

In the meantime, tourists will have to live with New York's mystifying on- and off-duty lighting signals, while dreaming of the clarity designers can impart. LED rooftop lights envisioned by the architectural firm of Weisz + Yoes would flash availability in plain English: "Maybe," "Nope" and "I'm Free."

The extra-tall CABsule, designed by CityStreets, would transport standing passengers as well as seated riders, and have space for a wheelchair. Hybrid Product Designs' MiniModal, with hybrid engine and raised glass roof, would be equipped with double doors and a sliding ramp for wheelchair access.