In a laboratory where some of the eye-popping special effects for the first "Star Wars" film were created, college professor Jason Leigh sits behind the steering wheel of a Mercedes-Benz simulator that is tooling -- and tolling -- along the Illinois tollway.

This computer-animated trip on the toll road is not part of some new movie production. Rather, it's taking place at the University of Illinois at Chicago in an experiment using volunteer drivers of various ages, including truckers, to devise new tollway signs to help direct drivers to pay their tolls.

The goal of the project, commissioned by a contractor working for the Illinois State Toll Highway Authority, is to come up with signs that are easier to understand and to improve safety by giving drivers more time to get into the correct lane to pay their tolls.

Some drivers, for example, are baffled by the intent of an existing tollway symbol, dubbed the "cactus arrow," which is designed to direct I-PASS users to stay on the mainline highway for electronic toll collection and cash-paying customers to get over into the right lanes to enter the toll plaza, officials say.

"We've heard concerns from drivers about confusion over the existing signs," toll authority spokeswoman Joelle McGinnis said. "Some motorists, mostly occasional tollway drivers or people from out of state, are failing to understand the difference between open-road tolling and the need to divert to the right to pay cash tolls."

As Leigh drives down the middle lane, his attention is focused on two 30-inch color screens designed to mimic what would be seen outside the car's windshield. Large overhead signs featuring experimental symbols and text instructing drivers to prepare for the open-road tolling and cash lanes 1 mile ahead come into view as Leigh drives at the pre-set speed of 60 m.p.h., slightly faster than the speed limit but considerably slower than is the custom for many Chicago-area motorists.

"I know that when I drive on [Interstate Highway 294, or the Tri-State Tollway], most people are going about 80 [m.p.h.]," said Leigh, director of the university's Electronic Visualization Laboratory.

With open-road tolling in place across the 274 miles of the Illinois tollway and with the Federal Highway Administration still working to develop national signage standards for electronic tolling, the toll authority is attempting to lead the way in the science of toll signage by conducting tests at the UIC laboratory and by placing the test signs at different locations on the tollway system.

Demonstrating the steps of the recent driving-simulation experiment that included 40 participants, Leigh presses a button on the steering column at the moment he sees the first sign, and his car's distance from the sign is recorded. He pushes the button a second time when he is able to interpret the sign's instructions, and another distance measurement is taken. The sequence is repeated when signs reading "Pay toll 1/2 mile" appear.

The professor pulls out from behind a taxicab and changes lanes to get over to the right to pay a cash toll.

The computer animation is strikingly vivid. Each test participant goes through 12 simulation runs under four lighting conditions: day, night, dusk and driving directly into bright sun. Participants also fill out a post-simulation survey in which the signs are rated in terms of how much the drivers like them overall, and they rank the signs as being the most or least visible and understood.

The simulation test results indicate that, generally, white signs are preferred over green ones and that text-only signs are more popular than signs with arrows and dollar signs inside rectangles to depict the toll plaza schematics.

But differences cropped up in connection with the age of drivers and how much previous experience they had driving on the tollway. Younger drivers and regular I-PASS users in the study liked signs that displayed a split diagram showing symbols such as the I-PASS logo and "$" along with the text "Cash keep right," while older drivers and non-I-PASS users found text-only signs more understandable.

The signs are being tested on the tollway as possible replacements to the existing signs at the approach to toll plazas, according to the toll authority.

The test signs are located on the eastbound Northwest Tollway (Interstate Highway 90) leading up to the Elgin toll plaza, on eastbound Interstate Highway 94 before the Edens Spur toll plaza, on the southbound Tri-State leading up to the Cermak toll plaza and on the northbound North-South Tollway (Interstate Highway 355) approaching the Army Trail Road toll plaza.

The signs will be shifted to different locations through the fall, and toll authority officials will solicit feedback from motorists. At some point later this year or in 2008, a decision will be made on which design to spend thousands of dollars on making new signs. If federal highway officials deem the design effective, it might be copied by toll road agencies across the U.S., officials said.

"There are different phases to go through before we come to a decision on what works best," said Michael King, the toll authority's chief of communications and marketing. "But we know that eye gumbo -- the clutter of too much signage -- confuses people."

The attention to improving open-road tolling signage is considered the next step in efforts to reduce crashes near toll plazas, which is where about half of all toll road accidents occur, officials said.

The absence of uniform design standards for toll-plaza construction was a contributing factor in a 2003 crash on the Northwest Tollway near Hampshire that killed eight women riding in a bus, an investigation by the National Transportation Safety Board concluded.

The safety board said the primary cause of the fatal five-vehicle pileup was a truck driver's excessive speed and inattention to traffic slowing down before the toll plaza, but investigation officials said the accident probably could have been prevented if the 1950s-style Hampshire-Marengo toll plaza had been replaced by the safer open-road tolling design now in place.

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