The first ancestor of the modern bus was referred to as an omnibus, a term that came from Latin and means “carriage for all.” These enclosed vehicles were pulled by teams of horses and could transport a large number of people - up to 42, in fact, for some double-decker omnibuses - around cities. The double-decker bus was an invention that expanded the availability of bus travel to many people, as the fare for upper level seats that were not enclosed were much cheaper than the lower level, enclosed seats.
As railroad technology was invented, the horse-drawn omnibus evolved into a horsecar. Essentially, this was an omnibus on a rail system rather than on the open street. The advantage was that riding on a rail system was much smoother, but the disadvantages of horse-drawn transportation, which included the cleaning of horse manure and the limited amount of time a horse could reasonably work, were still present.
By the end of the 19th century, most horse- or mule-drawn transportation shut down and new inventions took their place. Trolleys, or streetcars, ran on rails and were connected to overhead cables with electricity to power them. Buses began to be motorized, powered by petrol engines, enabling them to run longer and move faster than they could with animals as their source of power.
In the 1960s, buses began to take the shape they resemble today, as diesel engines were placed in the back of the vehicles to make easy access for passengers at the front. Since then, buses have evolved to be even more accommodating. They have flat floors and low steps to make access easy for all passengers. Many have handicap-accessible entries and seats, luggage and bike storage, and even bathrooms on board.
The next step in the evolution of buses is yet to be seen - they may be fully electrically powered, reducing harmful gas emissions. They may be self-driven, eliminating the need for a driver. Or they may be personalized in some way for each passenger, as advances in personal technology continue to be made. One thing is certain, however, the accessibility and practicality of buses will make them a useful form of transportation for years to come.