Our business is basically corporate, picking up execs at the airports, taking them to meetings, and so on. Yet, there was only the briefest mention of 'corporate services' on the Web site. That's where photos of the cars are very secondary to the background information about the firm, the little extras they provide, the assurance they can give to raise the 'comfort level' of the person booking the car for the executive. The site should have addressed what those services are, everything from their extra insurance, security training, references, how they treat celebrities, etc. I'd even go as far as putting photos of the office staff and drivers on the site.
People feel much more comfortable when they can see the people they're dealing with.
Offer assurance Let's talk about that comfort level. Comfort level has a lot to do with blame. In the computer universe, it used to be called the 'IBM Principle' in the days of big-iron mainframes. On the Web, you need to give the same assurance. Show them nothing will go wrong, give them enough to show that any reasonable person would know the risk is the lowest by dealing with your company.