Traveler's Aide: I reserved a rental car, why isn't it here?

— -- Question: I made a reservation with Hertz to pick up a car in September at the San Francisco location on Mason Street. When I arrived at the office, I saw many people sitting on their suitcases and waiting. I was told Hertz would not have any cars for five hours.

When I asked why they could not honor my reservation, they told me they "overbook just like the airlines." I also asked why did they not call my cellphone, which was on file with my reservation. The answer was "we just don't." They said the problem was caused by a big Intel convention in town.

I walked back to my hotel, where the concierge was able to get me a car at Budget which cost more than my Hertz reservation.

I e-mailed Hertz customer service twice. The second time I received a response after more than two weeks. Hertz apologized and offered $50 in vouchers for a future rental, but I'm still out the price difference between the rentals. Can you help?

—Steve Strauss, Corona del Mar, Calif.

Answer: Many travelers have had the irritating experience standing around, waiting for their rental cars. But five hours? That's unreasonable by anyone's standard. Hertz agrees.

Car-rental companies attempt to maximize their fleet utilization (and profit margin) by booking as many cars as possible. For some companies, that means overbooking rentals, on the assumption that some people won't show up to claim their reserved cars. However, despite what Strauss was told in San Francisco, Hertz does not knowingly overbook reservations, according to Hertz representative Paula Rivera.

"When customers make a reservation, they have every right to expect to receive the reserved vehicle at the time requested," says Rivera. "The fact that Mr. Strauss was advised that it would be a five-hour wait for the reserved car is unacceptable."

Most rental cars can be booked without penalty for no-shows, rendering fleet management more complicated. Factor in anything out of the ordinary—a large convention, a blizzard, a major sporting event—and you end up with dispirited travelers sitting on their suitcases in the rental car office. Hertz does move cars to help fulfill demand during special events, and each location takes inventory of available vehicles and reports it to the reservation center.

"Unfortunately, sometimes external factors prohibit this from being an exact science," says Rivera. "Periodically, customers will not return cars as expected, inclement/unpredictable weather may impact fleet availability and other factors may cause shortages."

In this case, Intel convention attendees had a hold on many Hertz cars, leaving Strauss out of luck. And although Strauss didn't like the answer, the San Francisco employee was correct that Hertz does not notify customers with reservations when no cars are available.

"It is not our normal procedure to call customers, as in most instances we would not know until the day of arrival about any issues and, at that point, for most people it would be too late," says Rivera.

But that doesn't mean customers should be left in the lurch. Car-rental companies could offer to pay for a taxi to a customer's hotel and back to the car location later, when a vehicle is available. Or help book a car through a competitor, with the original car-rental company paying the difference if the price is higher.

Turns out Hertz has these policies, and they should kick in if the reserved car isn't available within 30 minutes. But the policies aren't listed on Hertz's website, so Rivera says customers with policy questions should chat with a representative online or contact the company's toll-free reservations number.

Strauss didn't receive any such assistance, and Hertz said it would forward the details of his case to local management for corrective action.

Strauss' situation doesn't crop up that much during normal operations; renters aren't usually turned away at the counter—or subject to a protracted wait—because a location is entirely out of cars. More often, travelers find that they can't get the car size they reserved. In that case, they should get a free upgrade to a larger vehicle or a price reduction for a smaller one.

Hertz apologized for the inconvenience Strauss experienced in San Francisco. In addition to the $50 voucher it offered, Hertz also agreed to reimburse Strauss for the difference in his car costs, about $26.

How can you avoid trouble?

• If you have a reservation and no cars are available, ask the car-rental company to locate an alternative for you.

• Don't be late to pick up your rental car; the company could assume you're a no-show and give away your vehicle.

• Hertz customers have a few options to sidestep car-counter complications. They can prepay for rentals at a reduced rate and accept a $25-50 cancellation fee. Travelers can also make a guaranteed reservation for certain cars using a credit card. There's a cancellation penalty of $100 if you don't show up, but that might give you some peace of mind if you're traveling during a special event. (On the flip side, if the car you booked isn't available, Hertz will give you a $100 rental certificate.)

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Linda Burbank first began troubleshooting travelers' complaints for the Consumer Reports Travel Letter. She now writes regularly for Consumers Union publications and is a contributing editor for National Geographic Traveler. E-mail her at travel@usatoday.com. Your question may be used in a future column.