What makes a mass transit system great?

I've been looking at how different mass transit systems run and downloaded maps to my computer, some of which I will use here to demonstrate my points.
When you look online, you will find lists of "America's greatest cities for mass transit". Some lists have some really good information, and Wikipedia has a list of which cities have the highest levels of ridership.

First, here are the biggest reasons I can think of as a Millennial for why we want to have great mass transit systems:

1. On the user end, you can do more on a bus or train than you can if you are driving. I can read a book, read the news on my phone, get work done, almost any quiet activity I want. With a car I have to be focused on the road. As long as I am not carrying anything large it really makes no sense to drive.
2. The user can save a lot money on parking. Parking in New York tonight can range from $10 for an evening to $50 for an evening.[1] As long as it costs less than $5 for me to take the Subway into New York it is less expensive than driving, not including gas.
3. Parking in cities is a hassle and expensive. If you find the $10 parking lot, it will almost certainly be full because the lower price creates a much higher demand for that parking lot. During big events such parking prices just don't exist. It might be a long way from where you want to be, and all of this means you spend more time and money. Driving in traffic is also frustrating and no fun. Putting 50 commuters on a bus saves a lot of space on the road compared to 50 different cars in the middle of a big city. Everyone wins when there is good mass transit.
4. Light rail is faster than driving when they are available. If you take a light rail train and run it between two major cities in a metropolis (let's take Los Angeles at 3 million and Anaheim at 300,000 people) and put in an affordable light rail system you can bypass the traffic jam and get people to the center of the city. You can run them frequently, let's say every 15 minutes to start, and routinely fill them. As people find they are saving time and money it will become more popular. Running a train at 80 MPH (140 KM/H) can done while running a bus at 75 MPH (110 KM/H) in the center of a metropolis is impossible.
5. Light rail is inherently faster than buses. If you run a bus from point A to point B along the freeway and you have stops between A and B, you will probably need to leave the freeway and get back on the freeway which becomes real time lost for a commuter. A train can stop for a short period of time along the track and then start back up on the commuter routes from the suburbs and doesn't have to reenter the freeway. For longer routes, like Dale City to Washington or Fort Worth to Dallas, it makes far more sense to use light rail than a bus.
6. It reduces pollution which makes the environment more healthy and more pleasant.
7. More money stays in the local economy as opposed to going to the oil industry, acting as a local stimulus.
8. It creates local jobs that cannot be outsourced with the people who maintain the fleet of trains and buses, and drivers etc.
9. Bus rapid transit is an oxymoron. Buses running at rush hours get caught up in the same mess as every other commuter, meaning you save no time and end up with a mass transit system that is doomed because the buses won't run on time and people will choose to drive, meaning that the city will have wasted all of that money on new buses only to find themselves in the same place. Widening freeways will be shared with cars, which will make trips marginally faster, but if people then just go on the wider freeway (because if you take the narrower freeways people use them less even when they are going the same direction) you find yourself netting nothing in the end. If you find that demand is high (if the system is designed well it will be) you need to put on another bus on instead of just putting another car on the train, which is really simple, and the only way to make bus rapid transit to work is to make special roads for buses which don't stop between places and need to be regularly repaved, or just put in a track which doesn't have to be repaved every few years. If the buses are never on time, people with options won't ride them and the system will need constant funding to be poured in or close down. The other problem with Bus Rapid Transit is speed. Running a bus at 150 km/h (90 mph) is really difficult and inefficient. Running a train at 150 km/h however is quite normal for longer distances, and relatively efficient.
10. A smart system doesn't stop at every house for the long-distance trains. A smart system will have multiple layers, long-distance trains that can pass the congested carpool lanes connecting Washington and Baltimore for example with minimal stops in between, and shorter distance buses connecting stations with businesses and houses.
11. If the mass transit is faster than driving, people who have more money than time will have incentives to use it.

Those are the best reasons I can come up with, and there are certainly more. The other piece to the puzzle is how you set up the system. If you look at Munich, Cologne (Köln), Berlin, Paris, London, Shanghai, among other global cities you find that they are designed to get people from the outer towns into the center of the city and there are routes carrying people directly in a reasonable amount of time that beats driving in time, and the maps they have are designed to do it. Most of all, the most important routes are few in number, Munich has only 8 major trains, and 8 minor trains serving a metropolitan area of 2.6 million people. The schedules are predictable and go where the people are, so people use them. If they had less frequent service or ran the same 16 trains along routes people didn't live, it wouldn't be nearly as successful. Here are the most important points and a few examples:

1. The routes must be frequent and the local government must be willing to expand service when needed. Very busy people with more money than time who have cars and can afford to park are not going to rearrange their schedule around a schedule that doesn't fit their needs. Work schedules tend to be very predictable, people go to work around 8 in the morning, and leave around 5 in the evening. People want to get from home to work in as little time as possible for as little money as possible. The routes than must be efficient. If the routes run out before people get off work or are very infrequent around the time, people have no flexibility and will not use it. In Seattle, the Sounder between Tacoma and Seattle only runs at peak times, and not overly frequently either, you then have to take the bus which leaves out other suburbs, which takes the same amount time and serves fewer people.
2. Don't run buses or trains back to the station with no passengers. If you look at the Sounder schedule from Seattle-Tacoma it only goes at certain times and then goes up empty from Lakewood (south of Tacoma) to Seattle. This is ridiculous and wastes money. Always let the circuit run through the whole distance picking up passengers.
3. Look at the costs. People frequently look at the upfront costs of installing track (which most cities really don't need when starting) as a way of arguing against light rail. I found real numbers in an easy to read fashion here: http://www.lightrailnow.org/news/n_newslog2009q2.htm#BRB_20090605 which shows as I expected (given Japan, Korea, Taiwan, and all of Western Europe have chosen this) that the real cost of buses when calculated is not as low as people think in many examples and we need to take in all pieces when deciding which is right, beyond the costs of congestion.

The biggest issue is comparing the costs of rail vs. other methods, and this becomes very complicated. I have found good hard numbers that have been researched at the NY Times, APTA, and this advocacy site. One good source analyzing Britain's spending found that the privatized British Rail is costing far more than roads, but this is in fact due to privatization and costs between 1.5x and 2x that of other European nations. America's costs are close to that of Britain, and we also have private infrastructure. It seems like public goods that are not competitive should be public. The New York Times has pointed out while acknowledging his bias that it is hard to make AMTRAK profitable. The best way to get around this would probably to make the railroads public, because they are public in most of Contintental Europe and they are much less expensive to run The University of Leeds produced an amazing paper analyzing the costs of Finnish and Swedish railways, which like most of economics found the variability was huge and there are ways to make tracks less expensive by upgrading, and I recommend it to people who have time to read a very thorough statistics paper, because some of the ideas could help reduce the costs of transportation here in America, like upgrading the tracks so they don't have to be repaired as often.

The biggest question when designing a mass transit system is whether it will make sense for the community. If it costs 20 cents per passenger mile and there are 10.3 billion passenger miles (1 million passengers travelling an average of 35 miles round-trip 300 days a year) in one year the cost would be around $2 billion to maintain the track. (which is of course extremely rough) When deciding whether to build we need to figure out if the community will receive over $2 billion in benefits to the local economy. If those 1 million people were going to pay over $6.67 for parking for one day ($2 billion divided by 1 million divided by 300), than that alone will be saving the difference for the economy in savings and every passenger will be saving personal money. Another way to calculate is if this saved those 1 million people an average of 30 minutes a day 300 days a year and the average workers is worth $20 per hour than one would be saving $3 billion in opportunity cost right there. Both of these ways of calculating savings can then go to the economy in a better way, without the savings of gas, congestion, worker's time, and emergency services! Looking at the opportunity cost of a situation frequently gives a much different picture than first appears, and it is always more accurate. I am certain this is why European and Chinese cities have done massive investment in their mass transit, because they look beyond the immediate cost when investing in their economy. Because of this, I am not too worried about the costs of mass transit in cities if they are done correctly and people know they exist.

This is a very complicated issue the more I look at it and it is very easy to stop early before bringing all data, About.com shows that the difference between rail costs goes between $451 in Dallas to $124 in Salt Lake City, so making the decision of which is better is highly variable and has to be done on a case-by-case basis. Basically, by playing our cards right we can get the advantages of high speed mass transit in our larger cities which is synonymous with light rail, but only if we choose to.

If we can get the benefits for riders along with the cost savings, there is no reason we shouldn't do it, and this is why we need to have economists who are able to publish excellent studies on this issue where people can find them. If we can save money and lives by reducing congestion, accidents, than we have to. There is a lot of work to be done.