This city of '70s - where change has been measured in terms of most, fastest and biggest - today faces the possibility of becoming in the 1980s just another has-been American city.

More than a thousand people move here each week to tap the seemingly unlimited prosperity that has made Houston the richest jewel of the Sun Belt, but now their cars and those of current residents are adding so much traffic, 2,011 vehicles a week, that the resulting traffic is apparently costing the city jobs.

The difficulty and expense of moving people and goods has begun to raise the cost and lower the convenience of doing what is known here as "bidness." This has been a major change for a city that pursued as religion what one banker calls "a favorable climate" for industry.

"Houston is losing office locations because of its traffic," says L. Clinton Hoch., executive vice president of the nation's premier corporate relocation consultants, the Fantus Co., which serves 212 of the Fortune 500. "The problems are very bad and our clients know it."

"The day of the automotives society has really caught up with Houston."

While some experts here disagree that Houston has lost its mystical appeal to business, they conceded that for Houston - where public transit is a joke and sprawl demands cars - much of the city's future growth now turns on whether it can solve its dizzying traffic puzzle.

Thus, a referendum here next Saturday on whether to create the kind of buy system that other cities have had for decades has become something of a watershed from which Houston's future will flow. Transportation, business, political and urban experts generally agree that, without more public transit soon, Houston cannot be in the 1980s what it has come to represent in the 1970s.

"If Houston wants to continue to grow and preserve a decent quality of life, it has to at least take the first step toward mass transit," says Barry J. Kaplan, an urban historian at the University of Houston.

The referendum, which would create a transit authority and add one cent to the sales tax, will pit two typically Texan attitudes against each other: an almost genetic opposition to taxes and government versus a very real frontier pride in overcoming obstacles to expansion.

It comes at a title when the area's 2.5 million residents are also being confronted with other urban problems that many of them and many businesses came here to avoid. The Houston crime rate is perhaps the fastest-growing in the nation, and the cost of living here rose more in the past year than it did for the nation as a whole.

Traffic problems today are as bad as they are, in part, because a 1973 mass transit proposal was resoundingly defeated. But since then:

Vehicle registrations have risen 418,293 to 1,771,776, while freeway construction has stopped. No freeway capacity has been added since September 1975, and the last major addition was in 1973.

Rush-hour is lasting longer, up from a 1-to 1 1/2 hour stretch to 2 to 2 1/2 hours. The distance a rush-hour commuter can drive in 30 minutes has shrunk on the average from 17.4 miles to 12.3 miles in three years, and continues to decline. So slow is the going that many freeways actually pass fewer cars each hour than a year ago.

A smaller and smaller share of commuter is using what passes for a bus system. The city has only 420 buses, compared with Washington Metro's 1800 plus the subway. A fifth of Houston's are broken down on any given day. More than 65 per cent of this sprawling city lacks bus service. So not surprisingly, almost 80 per cent of commuters go to work by private car - alone.

All of this is beginning to exact a toll on businesses, many of which moved to Houston to get away from traffic congestion and to enjoy lower costs.

But some downtown firms now sunsidize parking at up to $70 a month to entice secretaries to work downtown. Twelve companies are buying monthly bus passes for workers, and 18 companies operate what is said to be the nation's biggest fleet of van pools - 250.

New federal air-pollution standards are requiring industry to offset new pollution by reducing filth from existing sources. Without reductions in auto exhaust here, federal officials say, such things as new refineries and petrochemical plants may have to locate elsewhere - taking the jobs with them.

Mayor Jim McConn warns that if the area does not develop mass transit "the people we presently have will find it difficult to get around, and unemployed minorities can't get to where the jobs are."

Says J.L. Taylor, director of economic dvelopment for the Houston Chamber of Commerce. "Houston's success has always been based on a series of small advantages over other cities - low taxes, transportation, people for example.

"A lot of those ad advantages are shrinking, and some may go altogether. If transportation goes down, we could swing to the negative. If this referendum does not pass -"

To be sure, no one is portraying Houston as, say, the next Newark. It is still the nation's third largest port and the world's energy capital. The job market will continue to grow as businesses already here expand, experts says, and so the question is, how much will it grow?

Enough to provide, jobs for all of those who move here? Enough for the city's young people? After all, one-half of the people here are under 27.

In this sense, the transit vote in Houston, the nation's fifth most populous city, may be the most important municipal voting in the nation this year.

What the referendum is not about is setting up a subway or rail transit system. All it would do, for $1.3 billion in local money, is provide the kind of bus service most cities have had for years: more buses, park-and-ride facilities, exclusive bus lanes and so on, including overhead busways that could be later converted for rail or other automated vehicles. A new transit authority would be created to run it.

A rail system for this sprawling metropoli - you could fit Boston, Denver, Atlanta, Louisvilla, Detroit and San Francisco within the city's 540 square miles - is impractical.

It woud, for example, take five times as much rail construction here to reach the same number of people that the money-losing BART system is available to in San Francisco.

And the Houston plan is seen as a pay-as-you-go-proposal, to be financed by federal aid, fares and the one cent sales tax increase. Much of the opposition to the transit referendum centers on the sales tax, which some people say would hit the poor and the elderly the hardest.

Supporting the plan is a coalition of groups so diverse as to reflect the sense of how important mass transit is to the area's future. The major Hispanic organizations and leaders want it approved - as does the chamber of commerce. McConn has been adjoined by two former mayors in support of the system - a political coalition that represents Houston's three ideologies: far right, right and moderate.

Whether that can overcome the city's antitaxation, antigovernment mood is unknown. The Texas Legislature has been in special to further cut taxes in a state at the bottom of the nation in tax burdens already.

What supporters hope they have going for them is the day-in-and-day-out suffering of a population that has become so auto-mated that one freeway just crumbled. When a major link opened into town in 1962, it was projected to carry 120,000 cars a day by 1980. By 1971 it was carrying that many, and up to 180,000 cars a day when it was closed this spring for two years of repairs.

The traffic it once carried has been diverted to other, already crowded freeways, and the rush-hour torture is barely eased by KIKK radio playing such favorites as "Honky Tonk Women Love Redneck Men."