DEARBORN, Mich. (AP) -- Every morning, just after getting coffee, Mark Fields fires up his laptop to pore over a computer model showing real-time U.S. auto sales figures.

On this morning in the middle of May, the man who heads Ford Motor Co.'s Americas operations has seen enough.

The line on a chart showing subcompact car sales for the first two weeks of the month goes almost straight up. The one for pickup trucks, Ford's biggest profit center, runs almost straight down.

High gasoline prices and the economic downturn are changing the market far faster than anyone anticipated. Without action, Ford would be making too many trucks and not enough cars, a recipe for a balance sheet peppered with parentheses.

"This is going on 10 weeks where we're seeing this not get any better," Fields recalled in a recent interview. "So we'd better act, and we'd better act now."

Eleven miles away at General Motors Corp., they were reaching the same conclusions. Consumers were delaying big-ticket purchases. Those who bought weren't going for GM or Ford trucks and sport utility vehicles, instead snapping up just about anything that gets more than 30 miles per gallon.

At both companies, executives were alarmed. Eventually they made almost desperate decisions that will cost thousands of jobs, change the vehicles people drive and determine whether their businesses survive.

"We need to get in front of it," Mike DiGiovanni, GM's executive director of global market and industry analysis, recalls saying. "If you wait too long on it, the pain would get a lot worse."

While both companies say they took quick action, critics wonder why they didn't make more fuel-efficient vehicles sooner. After all, there were many signs that gas prices would do nothing but rise.

"Obviously they were making just too much money off their SUVs and pickups," said Roland Hwang, vehicle policy director for the Natural Resources Defense Council. "They couldn't really fully conceive of a world where they would have to rapidly extricate themselves from those markets and those profits."

At GM and Ford, the pain came quickly. Ford was first, announcing on May 22 that it would dramatically cut truck and SUV production and slash its salaried work force. Factory closures are possible when the company announces specifics next month. A week later, Ford announced accelerated plans for a super-compact car to be built in Mexico and sold in the U.S.

Ford also abandoned its long-stated goal of turning a profit in 2009 and now says it will be difficult to break even next year.

GM followed with larger, more specific cuts, announcing at its annual shareholders meeting June 3 that it would close four truck and SUV factories, cutting more than 8,000 jobs. The company, which is clinging to its title as world's biggest automaker, also announced it would build a new small car in the U.S., powered by a 1.4-liter four-cylinder engine capable of getting up to 45 miles per gallon of gas.

But neither company's new compacts will reach showrooms for two years, and when they do, their profit margins will be far smaller than those from trucks and SUVs. Both automakers know they'll have to make it in the meantime with models already on the market or ones that are planned for the next year.

Industry analysts now are starting to question whether both companies, as well as Chrysler LLC, will have to borrow billions more to cover losses until sales recover.

As late as February, things were going pretty much according to both companies' plans. Sales weren't great, but their main barometer of the market, full-size pickup trucks, was holding up at 13 percent of U.S. sales, according to Ward's AutoInfoBank. Each automaker had rolled out new cars in expectation of a gradual shift from trucks to cars, and the cars were selling well.

But Digiovanni said oil prices in February began to rise, still not to an alarming level because they were consistent with previous seasonal spikes. Gasoline was still at a nationwide average of $3.03 per gallon.

In March, though, pickups' share of the market dove to just 11.6 percent and gas rose to $3.24.

"That's when I said 'Red Alert,'" Digiovanni remembered. "We're worried."

The share dropped to 10.8 percent in April, and when Ford's computer model predicted only a 9 percent slice of the market for trucks in the first half of May, CEO Alan Mulally decided to turn the giant ship faster than it had ever turned.

Ford would cut truck production and move as fast as it could to retool factories that make cars and crossovers. It would speed up plans to move small cars and trucks to the U.S. from other areas of the world and slash the normal three- or four-year time frame from design to build.

By May, gas prices had soared to $3.77, and both companies also were experiencing huge price increases in steel and other commodities.

When a market segment such as pickups moves up or down even one-half percent in a year, automakers consider it significant. Four points in 2½ months "puts it into perspective," Fields said.

"We are reacting quickly," he said. "We are reacting more quickly than we ever had in the past."

Even critics say it would have been nearly impossible for the automakers to predict the 74-cent-per-gallon spike in regular gas prices between February and May.

Although Ford's computer model, developed by a physicist and programmer in its research center, can pinpoint real-time retail sales numbers for the whole U.S. market, no company has a model to predict the future with any degree of certainty.

Still, George Pipas, Ford's top sales analyst, said the company saw change coming several years ago and was moving to tilt its model lineup smaller.

"The direction we were headed was based on the point of view that small cars were going to increase their share of the market and trucks and SUVs were going to be less," Pipas said. "It was the speed with which we got there. So we've got to fast-forward the elements of our plan."

Whether Ford, GM and Chrysler LLC can go forward fast enough remains to be seen. But even Hwang of the Natural Resources Defense Council says he thinks the companies will have a brighter future because they are more focused on fuel economy.

"There's no reason why Detroit can't emerge leaner, stronger, more fuel efficient and more sustainable from a business and environmental perspective," he said. "Fuel efficiency is not just because you want to help save the world. It's because you need to save your company."