I recently needed to book a rental car, so I started the search where all my travels begin, SideStep. The usual suspects and rates were quickly displayed, but it was a deal for CarRentals.com appearing in the sponsored links that caught my attention.

Thanks to the Compete.com toolbar, I checked to make sure CarRentals.com was a trusted site with decent traffic. Sure enough, they were, and I quickly locked up Dodge Caliber (or something similar) provided by Dollar.

As seen below, CarRentals.com ranked #9 in November in terms of unique visitors for car rental reservation sites and 10% of those visitors booked a car.

I was confident in my choice for a minute, but doubt set in when I realized my SkyBus flight (great deals, no frills) was scheduled to arrive late in the evening. Not wanting to be stuck in Columbus, Ohio without a rental car if things went wrong, I reserved a back-up with Hertz for a few dollars more. After all, you don’t have to pay to reserve, so better safe than sorry.

That got me thinking, how many other people reserve multiple cars for the same trip?

The table below ranks the above sites by the % of people that reserved another car on a different site during the same internet session. Obviously, I’m not the only one who likes to have options. 11% of carrental.com bookers also book a car someplace else at the same time.

It’s a good thing I did, because when my flight arrived in Columbus a few minutes late, Dollar was closed and nobody left the keys to the Caliber. Hertz, however, was waiting for me a few feet away.

For rental car companies, double bookers become a critical segment to focus on. Follow-up messaging and customer service play a major role in the decision process. Consumers have options and it may be the email upgrade offer received the night before or it may be the number of people in line at the counter that sways their final decision.