It's hard to lie to GUS.

GUS, the Geographic Underwriting System, is a computer program allowing insurance companies and agents to quickly and more accurately quote auto, wind, fire or crime insurance rates without relying solely on information from potential insurance customers.The IBM-compatible software, developed by the Insurance Services Office (ISO) here and introduced last week, contains community boundaries, street addresses, postal carrier routes and ZIP codes, said Philip D. Miller, senior vice president and chief actuary of ISO's special products department.

Distance traveled and proximity of the insured structure to wind, fire and crime hazards are two of the criteria insurance companies and agents use to compute rates, Mr. Miller said.

A wrong answer to the question, "How far do you drive to get from home to work?" could mean a huge difference in the premiums charged, the executive said.

"You type in point A and B and the distance is computed," Mr. Miller said. ''The alternative would be the agent taking out maps to locate streets and going out on inspections."

Information currently is available on wind, fire, auto and crime hazards, but the system will be expanded early next year to include an insured's proximity to contaminated sites on the Environmental Protection Agency's Superfund cleanup list, the ISO executive said.

Other potential uses include pinpointing the number of insureds located near earthquake fault lines, potential brush fire areas and major windstorm hazards.

"Insureds can load in databases to see where their risks are geographically," he said. In turn, that information can be used either to cut back marketing in catastrophe-prone areas or increase it in areas where the company wants to increase market share.

GUS currently provides information in four areas:

* Windstorm, including whether the location of the building to be insured is eligible for participation in state windstorm plans. Also included is proximity to the nearest large body of water, historical wind events at the site, extended coverage and Group II zones for personal and commercial lines and territory codes for personal and commercial lines.

* Auto, including auto territory codes and the distance between an insured's home and work address, measured as the probable minimum driving distance as well as the straight-line distance.

* Crime indexes including arson, auto theft, robbery, aggravated assault, burglary, aggregate crimes against persons and aggregate crimes against property.

* Fire, including the location of fire departments and hydrants in relation to the insured property.

Mr. Miller said the system's programers are still collecting windstorm, auto and crime information for the rest of the country to add to that already collected from 48 states and the District of Columbia. Fire information is currently available only from Florida, where GUS was tested for a year, but that is in the process of being expanded, Mr. Miller said.