Efficiency of vehicles is measured by the amount of energy (work) that will propel the vehicle over a certain distend in a given time. It is also the amount of materials, energy, and labor resource needed to make and maintain it.
There is simply nothing that matches a bicycle in the distance and speed it can achieve using so little energy, the energy of a person peddling it. And it does this without producing any pollution or greenhouse gases other than that expelled by the cyclist. The human body is an amazing piece of machinery with muscles that can produce an enormous amount of energy using so few calories to move skeletal bones. No electric or internal combustion engine has such high efficiency. Human power is the only thing that powers a bicycle. The bicycle is simplicity itself. Granted there are some bikes with complex gears but nothing compared to the mechanics of any other vesicle man can make.
It has the speed of some of the fastest land animals and far more range. A fit cyclist can ride a bike 100-150 miles a day and perhaps a champion cyclist can do over 200 miles. An average person can cycle 10 miles in one hour. If there were no signal lights, traffic, and the street was flat one could cycle along Stevens Creek Blvd. from one end of town at Lawrence Expressway to Foothill Expressway and back in one hour going at a moderate 10 mph.
One cannot beat the economic benefits of bicycles. Even the most expensive bicycle would cost as much as the cheapest car. Its maintenance would mainly be to occasionally replace worn out tires and lubricate the chain and sprockets once a year and change brake pads, all very simple and inexpensive jobs that do not require a mechanic or computers. Every few years the spokes may need some adjustments. No need for fuel or oil changes. Cars cost hundreds of time more to buy and maintain and require some source of fuel or external energy to run.
How about other non-operating expenses such as insurance, licenses, registration fees, smog checks, etc.? None of these are required of bicycles. One might insure the most expensive bicycles but this is optional and rarely done. Due to the lower price of bikes things such as sale tax are much lower and there are no other taxes associated with bikes unlike the excise tax for car tires.
How about the efficiency of carrying loads? Granted a car can carrier larger and heavier loads than a bicycle but in terms of efficiency of energy and weight of vehicle to weight of load bicycles win hands down. I own a shopping cart which attaches to the rear of the bike so it can be pulled behind it with a load rating of 50 lbs. My bike weight about 35-40 lbs. It can be quickly detached from my bike and the pull bar folded down revealing a handle that I can pull by hand like a basket cart. There are all kinds of clever carts and trailers that can carry large appliances on a tricycle. You’d be amazed at what bike like vehicles are capable of in terms of carrying large and heavy loads.
Even walking takes more energy to do than riding a bike because we must also use energy to carry our weight while walking. And one can ride a bike much further and in far less time than by walking or running without breaking a sweat.
As for comfort this is not an efficiency factor but in spite of the fact that cars have bikes beat hands down there are bikes like the Elf which can carry up to 3 people and are enclosed for the most part for bad weather areas. There are also electric assist bikes that have a motor which eases peddling such as up hills and for long stretches of road for those like me who are not very strong. The Elf is electrical assist. I own an electrical assist folding bike the easily fits in the trunk of my wife’s car for trips.
So if one is looking for a low cost, low maintenance, no energy, no pollution, high efficiency mode of transportation it is likely sitting in your garage gathering dust. It is fun to ride and a great source of moderate to high level exercise. See the world in true 270 degree 3-D with true surround sounds of nature. Dust off your bikes and try it out. But watch out for those highly inefficient, heavy, and dangerous cars.