State-of-the-art strategic transportation planning is admittedly complex and difficult. In particular, it is necessary to view the evolving transportation system as a whole, rather than as individual components. The reason is that the success or failure of each individual component depends upon the symbiotic effects of all of the other components working together with it.

As one simple example, many people have noted that I-95 North is heavily congested. The intuitive solution for this problem, proposed by many citizens, is to extend the MetroRail system parallel to I-95 North in order to take a substantial share of the traffic off of I-95 North. Yet, professional transportation planners know that such a simple "solution" nearly always fails for a variety of reasons, not mentioned or known to the citizens at the recent Transportation Summit Forums. Actually adopting such plans and committing them to a referendum almost guarantees a political disaster after the first few billions of dollars have been spent on them without providing any significant relief to traffic congestion.

Experience shows that the problem of steadily increasing traffic congestion can only be solved by a substantial "intermodal shift"¹, ²

• from the mode of transportation based upon privately-owned vehicles
• to the mode of transportation based upon a public transit system.

Experience has also shown us that such a substantial intermodal shift is very difficult to achieve in "Sun-Belt Cities" in the USA, because they typically cover large areas with a relatively-low population density. Therefore, "Sun-Belt Cities" pose a more-difficult challenge for transportation planners than older cities with a higher population density in the main core of the city (such as New York City, London, and Paris). In particular, "Sun-Belt Cities" which have already made the strategic error of building expressways to and across their core downtown areas are extremely difficult cases. As a result, Miami-Dade County needs the best national and international advice we can obtain to solve our traffic congestion problems.

Miami-Dade County is only at the beginning of a difficult transition, which will require education of our citizens in order to achieve a solution. As an example, too many citizens still naively want a better public-transportation system primarily to encourage "other drivers" to make the intermodal shift, so that they can continue to drive their privately-owned vehicles as before, without congestion caused by those "other drivers". This will not work in practice without dividing our population into 1st-class and 3rd-class citizens in ways that are not politically acceptable. Rather, a new and expanded public-transportation system must appeal sufficiently to all drivers that most will want to use it whenever possible.

We all need to learn and understand how and why the necessary intermodal shift ³ from privately-owned vehicles to public transportation is dependent upon the following 6 parameters:

It appears that most drivers of privately-owned vehicles assign the highest priorities to the top parameters and the lowest priorities to the bottom parameters on this list.

The "key factor for success" in reducing traffic congestion is how the values for these parameters combine to make an intermodal shift sufficiently attractive for a large number of drivers to switch to public transit for most of their intracity travel.

Going back to the example of proposals for extending the MetroRail parallel to I-95 North, we can easily identify the following obstacles to encouraging any drivers currently using I-95 North to make an intermodal shift:

• The most important factor upon their intermodal decision is that the time from when they leave their starting point (usually the door of their house) until they reach their end destination (usually their place of work or for various other visits) must be shorter than currently when using their car for the whole trip.
• If the speed limits on I-95 North average 70 mph, this means that the average speed of MetroRail trains parallel to I-95 North will need to be much higher than 70 mph in order to compensate for 
  • the lower speeds and waiting times for connecting public transportation, including MetroBuses, 
  • lost time when the MetroRail stops at stations along the way, 
  • etc.
• It appears that the current average speed of the existing MetroRail trains is about 42 mph. It would probably need to be at least 100 - 120 mph between stations along I-95 North in order to sufficiently compensate for the other lost time before a significant number of drivers would make the intermodal switch! (Is this technically feasible with the existing MetroRail technology and have the extra costs for operating at these speeds been included in budget estimates?)

This example also shows very roughly why an expanded MetroBus system by itself would not significantly slow the increasing congestion on our highways.⁴ 

Buses

• usually travel on the same roads and highways as privately-owned cars (with a few exceptions such as the Busway parallel to South Dixie Highway), 
• usually travel at about the same speeds as privately-owned cars, 
• but they lose time for each stop. 

Therefore, the total time for a trip will nearly always be longer than when using a privately-owned vehicle and therefore there will be virtually no intermodal switch from driving cars to public-transit buses. (The same considerations are also often relevant for light-rail trolley systems.)

There are several potential goals that would encourage us to expand the current MetroBus system. But, for the purpose of reducing traffic congestion, this is only feasible when this expansion is done in parallel with expansion of rapid-transit systems, such as Metro-Rail. In this case, the slower MetroBus system provides the fine feeder network for improved coverage into the higher-speed rapid-transit system providing the main arteries of the overall network. For this to work, we must understand that

• the rapid-transit system must be sufficiently faster than competing privately-owned vehicles on public highways
• to save enough time to compensate for the slower buses in the feeder network, 
  so that the total trip time (combining slow bus and fast rapid-transit segments) becomes less than for privately-owned vehicles.

It appears that the existing MetroRail system was designed without due consideration of either

• the 6 parameters defined above as the "key factors for success" in achieving an intermodal switch by a large fraction of all drivers of privately-owned vehicles or
• the options left open for later expansion.

The first point appears to be the reason why the existing MetroRail system has only been partially successful in achieving its goals, whereby the ignored parameters of speed and coverage have been most relevant. Perhaps we should consider ourselves lucky that the end result was not much worse than it actually was. Likewise, an extension of the MetroRail system parallel to I-95 North could easily be more of a disaster if these parameters are ignored.

Designing a MetroRail system to compete speedwise with Dixie Highway, with its speed limits between 35 mph to 45 mph and with many stop lights - and only partially succeeding - is a dangerous omen. Designing a new MetroRail extension to compete speedwise with I-95 North with typical speed limits of 70 mph and no stop lights is an entirely different "ball game". It is like pitting a high-school baseball team against a major-league baseball team. We won't win this ball game unless we do a much better job of planning.

High-speed heavy-rail electric transit trains typically use either

• an overhead wire hung from poles or
• a 3rd rail on the railway bed

to transfer electricity to the train, with the normal steel track serving as the other "ground" connection. The first option is slightly more expensive but the second option poses serious safety problems if any of the track is at grade level where pedestrians, animals, or vehicles may cross it on foot or on wheels. The existing MetroRail system is an elevated system which is very expensive per mile of track and uses the 3rd-rail system, like most subway systems around the World.

How should the existing MetroRail system be extended for a long distance in parallel to I-95 North? There are two major technical options:

• The new extension can use the same 3rd-rail technology as the existing MetroRail system, requiring it to use an elevated railway at a very high cost of construction per mile where it would not otherwise be necessary.
• It can use an overhead wire hung from poles to feed the electricity, allowing most of the railway to be at grade level, thereby substantially reducing the costs for construction and maintenance, but at the expense of not being compatible with the existing MetroRail System.

The incompatibility of the second option above can be solved technically by:

• creating a transfer station where the old and new systems meet, where passengers can disembark from one train and transfer to another train with the other technology, causing some delays and inconvenience for passengers that reduce the attractiveness of the overall system;
• converting the existing MetroRail system from a 3rd-rail system to an overhead- wire system in order to achieve technical compatibility, at considerable cost for the conversion; or
• converting the current trains so that they can switch back-and-forth from getting their electricity from a 3rd-rail system to an overhead-wire system, which would also be expensive. 
  Are there cost estimates available for these options that can be presented to the citizens?

Roads in Miami-Dade County are laid out mainly on a rectangular grid with "streets" running E-W and "avenues" running N-S. This has many practical advantages. However, the starting points and destinations are usually not on the same E-W street or the same N-S avenue, but rather are located on a diagonal. In addition, the Atlantic Coast generally follows a diagonal from NE to SW. 

As we know from geometry, the distance along the diagonal hypotenuse of a triangle is shorter than the sum of the lengths of the two sides. We may need to use this principle creatively in order to achieve a sufficient speed advantage for public transportation over privately-owned vehicles at a reasonable cost. In particular, the old railroad rights-of-way often follow the general diagonal, such as the MetroRail and and Busway parallel to the diagonal South Dixie Highway on a former railroad right-of-way.

Due to the high costs for acquiring new rights-of-way when buildings need to be cleared, we are often limited financially to using existing railroad rights-of-way, particularly when they are no longer used by trains, such as the way in which the MetroRail and Busway along South Dixie Highway use former railroad rights-of-way. In fact, one of the starting points for transportation planning should include a map showing all railroad rights-of-way in Miami-Dade County, including those that are no longer in use and those with still occasional use.⁵

It is technically feasible for high-speed transit trains to share track with low-speed freight trains along the same right-of-way. However, the track must be upgraded to the standards for high-speed transit trains from the lower standards for low-speed freight trains, such as by straightening and leveling the track as well as by using welded rather than bolted joints. There must also be parallel track available for high-speed transit trains to pass low-speed freight trains. If there is very little traffic with low-speed freight trains, it may be possible to simply schedule these trains during off-peak hours when there is little high-speed traffic. However, grade crossings with streets and roads are more dangerous with higher-speed trains and this may require tunnels or bridges to eliminate most grade crossings. 

A technical proposal has been made for extending the MetroRail system southwards on the existing Busway (former railroad right-of-way) using bridges as MetroRail stations over each of the relatively few crossing streets and with the rest of the track inexpensively at grade level.⁶ This concept could potentially also be used on other railroad rights-of-way, even allowing slow freight trains to continue using their grade crossings while all rapid-transit trains would go over the crossing roads. However, safety considerations will probably require that such extensions to the MetroRail System user overhead wires for electricity, making them incompatible with the existing MetroRail system.

With hindsight, the planners of the existing MetroRail system should have known that it would only be truly successful in reducing traffic congestion if it is later extended with substantially more coverage and with substantially higher speeds, but the future costs for such later expansion can only be justified if most of the future extensions are at grade level requiring a different system of supplying electricity. With hindsight, the existing MetroRail system should have used the slightly more expensive overhead-wire system from the beginning, rather than the 3rd-rail system, in order to be technically compatible with future cost-effective extensions. It should also have been designed for and implemented with substantially higher operating speeds.

With foresight, the solution for this dilemma should be chosen not on the basis for one single extension of the MetroRail system, such as parallel to I-95 North, but rather for all of the extensions that will ultimately be necessary to achieve an effective solution to future traffic-congestion problems.

Modern public-transportation planning should start out with a

• fine grid for the total area under consideration and
• transportation surveys that identify each trip with
  • the grid cell where the trip begins,
  • the grid cell where the trip ends,
  • the time when the trip currently begins, 
  • the time when the trip currently ends, 
  • the modes of transportation currently used (with these times), and
  • the major highways used if the current mode is by a privately-owned vehicle.

(This data is difficult to visualize manually and must be stored in a computer data-base for making useful calculations.)

For each proposed model for the map or layout of a public-transportation system, we also need

• the proposed time table for each station or stop along each route and
• the grid coordinates for each station.

Using a computer, we can then calculate the total time from start to finish for each trip using the proposed model. If this time is less than for using a privately-owned vehicle, we will assume that it is attractive for the driver to switch modes to our proposed model. It can then be calculated how this traffic from many trips will be distributed across the proposed model, indicating the capacity and frequency of service that will be required on each route.

We can then try different competing models and small changes and variations in the main models for optimization to determine which model provides the greatest benefits for the least costs. We can also estimate the reduction of traffic on each major highway and compare costs of construction and operation with revenues from fares for each model.

The strategic planning for transportation in Miami-Dade County must be closely coordinated with other agencies of our Government, such as the Department of Planning and Zoning. If we agree that a substantial intermodal shift from privately-owned vehicles to public transit is necessary, zoning laws should be changed to distinguish between residential and commercial zones in ways that actively support a significant intermodal shift towards public transportation.

People can drive their car to a Park-and-Ride facility when they leave their homes, but can not use a car to get from a public-transit station to their destination (unless they have 2 cars, with one car always parked at the other end of their public-transit route). For this reason, most commercial zoning that creates significant numbers of jobs should be within easy walking distance from a station of the public-transit system. To the extent that planning for zoning has not taken this factor into consideration in the past, many jobs in Miami-Dade County may now already be located at places that will not be accessible to a public-transit system and hence workers at these locations will always be dependent upon driving their privately-owned vehicles to and from work. 

In summary, this is a complex process of analysis and design with many small pieces of interrelated information. Yet, with the modern technology of the Internet, it is possible to implement this process transparently with a large number of private citizens actively collaborating with their Government in this activity. A web site which 

• provides the same comprehensive set of documents and other resources to all participants and
• provides "discussion groups" for individual specific topics

can form the basis for such effective collaboration. In particular, many students in our high schools and universities can participate in specific technical areas of their interest - and learn about public participation in our government at the same time. In this way, our citizens as a whole can accept the final proposal as "their solution" to which they actively contributed.⁷ 

References:

The references with more detailed information are all available on the Internet.

It will be easiest to access these web pages if you use the version of this paper which is published on the Internet at: 

http://www.civicwebs.com/cwvlib/transportation/mdpt/strategic_planning.htm 

From there, you will only need to "click" on the hyperlinks to get to these referenced documents.

© Jack L. Davies 1994, 1995, & 2001