COALINGA, California (CNN) -- Noel Bosse and Ken Davis watch as the numbers keep spinning at the gas pump -- 70 bucks, 80 bucks. Gulp, guzzle, then it stops: $101 for about 25 gallons.

Gas prices in California are the nation's highest, already soaring over $4 a gallon in some areas.

The $100 fill-up has arrived in the United States.

"I think it's absolutely ridiculous," Bosse said with disgust.

Bosse and Davis are returning from Las Vegas, Nevada, to their home near Seattle, Washington. They're pulling a trailer full of Arabian horses with their passenger van.

Bosse says they're averaging 200 miles every fill-up, or 10 miles to the gallon. Watch how soaring prices are changing lives »

Bosse has been showing dogs and horses in competitions across the country for 35 years. With gas prices soaring, she's starting to rethink some of the upcoming shows.

"We're sitting here hauling a horse trailer, eating gas," she said. "I don't see how people make it these days."

California is home to the nation's highest average gas price, $3.87 for regular unleaded; diesel is pushing $4.43 a gallon, according to Troy Green of AAA.

San Francisco is the most expensive city, averaging $3.97 a gallon. However, a drive around the city shows that many stations have jumped over $4.

The national average for regular unleaded is $3.53 and rising daily. Last year at this time, it was $2.86 per gallon. According to AAA, 24 states and the District of Columbia are averaging at or above $3.50 a gallon for regular unleaded. The state with the lowest gas is in New Jersey, at $3.34 per gallon.

California Gas Crunch California is home to the nation's highest average gas prices. Here is a glimpse of prices across the state, according to AAA as of April 23:

San Francisco $3.97 per gallon; last year $3.47

 Los Angeles $3.85; last year $3.32

 San Jose $3.89; last year $3.36

 Sacramento $3.86; last year $3.30

 San Diego $3.88; last year $3.35



Green says Americans should expect the price to increase another 25 cents over the next month and continue to climb over the summer months.

"A national average approaching $4 a gallon should not be ruled out by consumers later this year," he said. Watch truckers head to Mexico for $2 gas »

AAA has seen that when gas prices hit "exorbitant levels," as Green puts it, Americans change their vacation plans. During such times, he says, Americans are more prone to travel closer to home, stay at less expensive hotels, eat at fast-food restaurants rather than fancier dine-in restaurants and plan more online trips looking for the best deals.

This year's record high gas prices, coupled with a slow economy and the mortgage crisis, have had a cascading effect. A person making $9 an hour needs to work nearly seven hours just to pay for 15 gallons at $4 a gallon, according to CNN.com's gas calculator. Interactive: How much do you need to work to pay for your gas? »

"It seems many American consumers are being hard hit from multiple directions, and their overall budgets are being maxed to the limit," Green said.

As for California, Green added, "It's unbelievable out there."

That's a sentiment shared by Diddy Dennis, a cab driver in San Francisco. He's been driving for nearly 11 years, and the gas prices are directly cutting into his wallet. He recalls the early 2000s, when people started complaining when gas out West started hitting $2.60.

"That looks like heaven now," Dennis said.

His big smile and warm laugh provides an air of calm in his cab, even if he's eating into his way of life every time he presses the gas pedal. He estimates that he's making about 60 percent less than he used to when he first started driving.

"It's really hitting us," he said.

San Francisco commuter Debbie Jasmin says she's stopped driving her gas-gobbling Expedition and started taking the subway to work more. She's also curbed summer travel plans.

"I don't really think we have seen the worst of it," Jasmin said.

At a San Francisco Chevron, Scott Roberts is stunned when he pulls into the station in his pint-sized Toyota Prius, which gets more than 40 miles per gallon. The person before him paid $115.80 for 27.9 gallons. The price at the station ranges from $4.14 for regular unleaded to $4.39 for supreme unleaded.

Roberts mutters the Lord's name in vain. "This is brutal," he said. "Today's the first time I've seen it over $4 in my lifetime."

By the time he's finished, it's cost him $43 to fill his Prius -- an amount that just a few years ago was reserved for giant sports utility vehicles and pickups.

Nearby, Dolly Sarlo fills up her black Mercedes. She says it's time for Americans to "vote with your dollars and to stop using gas" and use public transportation more.

"That would really, very quickly bring down the price," she said.



She then drives off. E-mail to a friend

CNN's Chris Lawrence, Gregg Canes and Wayne Drash contributed to this report.

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