There was a time when most rental car customers would have welcomed an upgrade to a midsize or sedan, a minivan or an SUV, but that was before gas was "upgraded" to $4 a gallon or more.
Now some customers say rental car companies increasingly try to pressure them to take the gas-guzzling bigger vehicles, even when they have reserved a compact. Car rental agencies apparently can't keep enough of the smaller, more fuel-efficient cars on lots to meet demand.
Aileen Goldstein, a marketer and frequent traveler, said she encountered pushy rental car customer service representatives on a recent trip to a trade show in Phoenix. They have "gotten a little harder" with their upgrade offers, she said.
"I try and watch whatever we spend," Goldstein said. "I still didn't know how much gas cost in Phoenix. I certainly didn't want a big gas-guzzler going short distances, and I didn't want to pay $80 when I could pay $40 to fill up a tank."
"They're lucky that people are renting cars in general," she added.
In response to skyrocketing gas costs, some frequent renters have updated their online rental profiles to say "No minivan or SUV." Others have waited in lengthy lines at customer service desks, enduring arguments with service representatives to switch to a compact car, they say.
However, industry insiders say the link between rental car customer service and rising gas prices is not completely clear.
To entice customers to take the bigger vehicles, renters say they have seen some rental car companies drop the prices of SUVs and large cars.
"It's kind of ironic, because usually the small cars are the cheapest," said frequent business traveler Michael Capel. "If the SUVs are sitting on the lots of the rental companies, they'll have to discount them."
Chris Brown, managing editor of Auto Rental News, called the increase in rates for compact and economy cars a "supply and demand issue."
He said, "It filters out to every other part of the auto industry. This is the environment we're living in right now — this is the reality we're living in right now."
A spokeswoman for Enterprise Rent-A-Car — the largest rental car company in North America, which also includes the National and Alamo brands — said her company has not lowered rates for SUVs and trucks.
"Overall, it has not been a strategy for us to lower prices on SUVs and trucks in an effort to rent them, as our customers still request and need them," Laura Bryant told ABC News in an e-mail.
Bryant said that while there is an increase in demand for smaller cars Enterprise's largest increase has been for full-size vehicles.
"Also, consider that, previously, people used to reserve an economy car, but actually hoped to luck out and get an upgrade — and that may not be happening as much anymore," Bryant said in her e-mail.
Brown said the situation with rental cars is a symptom of larger auto industry trends.
"This is a painful market adjustment that's happening," Brown said. "It starts with the major manufacturers, and the car rental industry is trying to accommodate that."
Brown defended national rental car chains, saying the companies' chief concern is superior customer service.
"They basically want to satisfy the customer," Brown said. "Customer service is extremely important to these car rental companies. At the end of the day, these cars are a commodity and how are they doing to differentiate themselves from other car rental companies is in customer service."