Travel guides and etiquette books offer advice about them.

Mobile phone applications help diners calculate them.

Oprah and other TV talk shows have dedicated segments to discussing and making recommendations about them.

Now, how about a primer for motorcoach operators (and their passengers) on tips and tipping?

After all, tips are a long-established aspect of the tour- and charter-bus industry.

They can contribute significantly to a drivers compensation and job satisfaction, and they can help operators recruit, hire and retain drivers.

So, how do operators go about making passengers aware that tips are a way of expressing gratitude for a job well done?

Or, has tipping become so customary no reminder is required?

Heres a roundup of comments from experienced coach operators on their tipping policies and practices:

Suggest recommended amounts when the customer inquires about tips.

"Our sales people, if the question of tips comes up, will give them a range of what a recommended tip will be. Well also say its not required, its up to you, but a standard is $1 or $2 per person, per day," says Jeff Polzien of Red Carpet Charters in Oklahoma City.

"If you check into a hotel and someone handles your bag, you might give him $5 or so. If a driver handles your bag and assists you in getting on and off the bus, its not out of line to give them $1 or $2 per day."

Tom Ready of Ready Bus Line in La Crescent, Minn., agrees.

"When customers call, we always tell them that $1.50 to $2 a head is customary," he says. "The guys work so hard, and theyre service people. Theyre with you day and night.

"We hope theyll do well on tips. That means its a successful trip. Thats a good sign the customers were happy, and they feel proud they worked hard."

Use forms, cards and other printed material to offer information on tipping.

"We have a customer-service card, its a travelers satisfaction report. Its a card we give customers at the end of the trip. It lists (tipping) recommendations," says David Annett of Annett Bus Lines in Sebring, Fla.

"Its really for education, what an expectation is. We dont allow drivers to have jars on the dash. Even if we didnt pass out the cards, I feel like the customers are pretty sophisticated and know when theyve received really good service."

Dennis Streif of Vandalia Bus Lines Inc. in Caseyville, Ill., says the confirmation form his customers receive before the trip contains the line: "Driver gratuity is not included in the cost but is very much appreciated if given to your driver." Its printed right above the signature line so chances are the customer will see it."

Its OK to add on a tip in certain situations.

"We do have a practice -- on certain trips that really tax the driver and you know the group isnt going to tip of building it in. We disclose it, and say were adding in the tip," Polzein says.

"We usually dont get any push back. Usually its conventions, when youre driving in circles all day in heavy traffic. People arent going to stop to give a tip."

Let the customer know that tips are earned.

"Our policy is we tell our customers, we dont require tips. We pay our drivers a good wage, and they work for wages, not for tips," says Marcia Milton of First Priority Trailways in District Heights, Md.

"If you feel they deserve a tip, then you can give them a tip, but we dont automatically add it on. We also say, if they dont do a good job, dont tip them. It shouldnt be something automatic. It should be something earned."

William Allen of Amador Stage Lines Inc./Amador Trailways in Sacramento, Calif., offers similar advice on tipping.

"I tell my friends, just wait and see, if the guy does a good job or a bad job," he says. "If for some reason he doesnt do a good job, if hes not out there helping you off the bus, if the ice chest isnt full of ice, then he doesnt deserve a tip.

"Some people say just put an extra $100 on the bill, and they dont have to be bothered with it. They pay the bill. I kind of frown on that. If a guy knows hes going to get an extra $100, whether he does a good job or a bad job, Im not in favor of that."