The New Rules for Business Rides in an Uber, a Driverless Car and More There's a proper time to sing, to sleep and to make small talk.

With self-driving cars starting to rule the roads, it's important to know what you can and can't do as a passenger. Here are some guidelines.

When driving the company car, is it tacky to belt out my best Katy Perry impression?
Jeanette Martin, management professor emeritus at the University of Mississippi and author of The Essential Guide to Business Etiquette: "Depends on how passionately you're singing! Remember that you're representing the company, so you need to be on your best behavior: no road rage, no giving people the finger, no texting or eating an elaborate lunch at the wheel. Most companies will also give you guidelines on whether you can use the car for personal errands or lend it to a family member. But if they don't, ask. You don't want to find out after your teen gets a ticket that she shouldn't have been driving."

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I'd usually chip in for gas when carpooling with a coworker, but she has an electric car. Should I offer to foot part of her electricity bill instead?
Patricia Rossi, business-etiquette coach and author of Everyday Etiquette: "You always want to show some gratitude -- beyond a verbal 'thank you' -- when someone spends their time, effort and, yes, electricity driving you around. If the coworker doesn't mention sharing costs up front, offer. If they wave you off, thank them with Starbucks or a gift card."

Can I catnap in a driverless car, even if I'm still on the clock?
Martin: "Most people who travel for work are putting in long hours later -- a convention trip, client dinners in the evening. So if you want to take a nap, that's fine. Just make sure your phone ringer is on."

Is it kosher to take a work call while driving?
Rossi: "For a big, important client call, never do that. For a smaller call or for something internal, it's sometimes necessary. No one enjoys hearing traffic or sirens in the background, but if you give people a heads up that you're in the car, it shows that you've at least thought of them and how it's not ideal. That goes a long way."

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Do I have to make small talk with my Uber driver?
Martin: "Only if you want to. There's no reason to feel guilty for working on your phone -- part of the reason you might take an Uber is so you can keep working. But keep in mind that the driver might be doing this on the side, and their day job might very well be in your industry or even at a competitor. So while texting is fine, be wary of talking on your phone about sensitive or confidential info."