Unbeknownst to many drivers, creating the perfect warning sound in a vehicle through its horn can be as much of an art as it is a science.
Herein lies the challenge. A horn, after all, "has to serve its purpose of alerting other drivers and pedestrians, while at the same time we try to make it as pleasant a sound as possible", says Victor Rangel Chavez, the global core design and release engineer for traffic and security horns at Ford.
"In order to achieve this, we use a dual note assembly that is engineered so that a high tone and a low tone work together to produce a harmonic sound."
While this carefully concocted sound might translate into a blaring "beep-beep" on the road, it can vary considerably depending on which country a vehicle ends up being driven in.
In Japan, for instance, Dan Edmunds worked for a car maker between 1990 and 2000, during which time he noticed a different sound for the horn compared with those in the United States. The main difference? The horn seemed more polite.
"The horn, sometimes, is used to indicate to someone that they can go ahead of you, as opposed to, 'Get the hell out of the way,'" says Mr Edmunds, who is now the director of vehicle testing for Edmunds.com, an automotive information site.
"It tends to be a friendlier pitch, and not as harsh."
In countries where the horn is more widely used, or the ambient conditions on roads are not ideal for the horn because it is simply too loud, some car makers say they look for ways to make the horn more "robust". In other words, they pump up the volume where anti-noise regulations do not stand in the way.
Drivers in parts of Asia prefer what is known as a trumpet horn, General Motors (GM) says.
The car maker began introducing more vehicles with that type of sound in China and India last year, even though many vehicles still feature a disc-based horn, which sounds "cheaper," GM says. The company is also looking to implement electronic horns into these regions, which are designed to be even more pleasing to the ear.
The platforms used to create different vehicles, including the horns in each, vary based on where a saloon, 4x4 or van may end up.
"There are different horns set up, depending on which country we're selling to and the regulatory aspects we're dealing with," says Jim Danahy, the chief engineer for GM's Buick Encore.
"Then, of course, we want the horn to sound pleasing. That's a little more tricky because some sounds are more pleasing than others."
Engineers have also tinkered with the components that make up a horn to ensure the safety feature lasts as long as possible.
GM says it has incorporated a tungsten component, instead of steel, which has increased the number of times a horn can honk before it needs to get replaced. The company says some drivers in China and India have burned through their horn's life within as little as three months.
"In those regions they typically see the traffic horn as another vehicle part you change out as part of the regular maintenance and the general preference of the people is that louder is better," says Mr Chavez.
But as a higher volume of relatively quiet battery-powered vehicles start hitting the road around the world, there is rising concern that pedestrians may not always hear one approaching.
"We have people working with the [United States] government to come up with regulations of what needs to be there outside of the horn, just to let pedestrians know that this vehicle is on," says Jason Wong, the lead global engineer for horns at GM.
"Most people, if they've never been in an electric vehicle, don't know if it's on or off if they just sit down and hit 'on,'" Mr Wong adds.
"Obviously, it gets even more dangerous for a pedestrian."
A US law known as the Pedestrian Safety Enhancement Act of 2010 has called for minimum sound requirements for hybrid and electric vehicles. As part of this process, the US national highway traffic safety administration issued a report this year that detailed the environmental assessment of various kinds of noises for this purpose. Some interesting suggestions from commentators include several who think the organisation should consider "pedestrian protection measures" that do not adversely affect the environment.
In other words, they suggest, car makers "should explore alternatives to artificial noise, such as non-acoustic pedestrian technologies [including transponder bracelets or shoe implants that alert when vehicles are present]."
The debate about what kind of noise electric vehicles should make will probably carry on for some time, as new rules are supposed to take into effect by the end of 2016.
Already, though, some car makers are testing different types of noises that may act as the warning sound of tomorrow.
"I've driven several electric vehicles and hybrids, some of which have a 'spaceshipy' noise," says Mr Edmunds.
In that case, vehicles may sound like they are going back to the future - perhaps to the 1960s, when models from the TV show, The Jetsons, zipped about in the skies.