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The movement of population further out on Long Island increases the separation of that population from the rest of the metropolitan area. Driving between Nassau-Suffolk (which has a population greater than that of the Pittsburgh metropolitan area) and Westchester, New England, Upstate New York and points west is only accomplished by going into New York City and out again. As population grows, people will be required, as they travel to the bridges at the western end of Long Island, to pass through a territory of congestion that will be made worse by the growing population itself. This is significant not only for the transportation of people, but also for the movement of goods.
At present, about 33 million trips are made annually to and from Nassau-Suffolk across the Throgs Neck, Bronx-Whitestone and Triborough bridges. These bridges are now nearing their capacity limits. If a new bridge is not built, traffic congestion on these bridges and on radial expressways will increase. The costs of goods movements will likely increase as a result. Finally, the people on the island will become steadily more isolated.
TRANSPORTATION OPERATIONS
Estimates were prepared of traffic volumes that would use each of the eight alternative bridge crossings for the years 1975 to 2000. Crossings range from 45,800 daily on the Sands Point-New Rochelle Bridge to 6,800 daily on the Orient Point-Watch Hill Bridge, both at base tolls. The three western bridge locations have much higher estimated traffic volumes due to their higher densities of population and, in part, to their lower toll structure.
Studies were made to determine optimum tolls, which maximize gross revenue. Generally, optimum tolls are higher than base tolls. They ranged from $1.50 at the Sands Point-New Rochelle Bridge to $4.00 to the two eastern bridge locations.
Secondary transportation impacts include changes in traffic on existing bridges and expressways. The Bronx-Whitestone and Throgs Neck Bridges, now at approximately 93 percent of their peak hour design capacity and expected to reach 100 percent of design capacity by 1975, would be relieved by building a new bridge.
The construction of any new bridge across Long Island Sound will relieve such facilities as the New England Thruway (I-95), Major Deegan Expressway (I-87), Long Island Expressway (I-495), and Cross Island Parkway. Typical is the effect of the Oyster Bay-Rye Bridge: it would reduce daily traffic on the Long Island Expressway west of Glen Cove Road (EXIT 39) by approximately 5,000 vehicles per day.
The construction of any new bridge across Long Island Sound will reduce the vehicle miles of travel now driven on eleven major expressway corridors in the region, with attendant reduction in air pollution. The Glen Cove-Rye Bridge provides the greatest reduction in air pollution, followed closely by the Oyster Bay-Rye Bridge.
The construction of either the Glen Cove-Rye Bridge or the Oyster Bay-Rye Bridge would increase traffic on the Cross Westchester Expressway (I-287). This is the only major facility, however, that is adversely affected to any significant degree. The eastern part of the Cross Westchester Expressway, currently carrying 32,000 vehicles per day near I-95, and with a design capacity of 54,000 vehicles per day, would have 10,500 daily vehicles added to its existing load in 1975 by the Glen Cove-Rye Bridge, and slightly less by the Oyster Bay-Rye Bridge. This can be readily carried out until at least 1980, and longer at optimum tolls. Improvements in the Cross Westchester Expressway should be programmed concurrent with bridge construction, however.
The opportunity for using the construction of one or more bridges across Long Island Sound to improve mass transportation operations was examined. Except for a limited amount of bus transportation that might be generated, no significant opportunity exists for improving mass transportation.
FINANCIAL CONSIDERATIONS
The financial consultant was furnished with estimates of net revenues for eight bridges from the year of opening to the year 2002, together with toll rates, estimates of construction costs, and the estimated lengths of construction time. The financial consultant then made certain assumptions uniformly applied to all bridges, including 40-year term bonds, a capitalized debt service equal to the maximum annual debt service requirement, and the payment of interest from bond proceeds over the construction period plus a one-year start-up period thereafter.
Since interest rates can vary significantly with the passage of time, and since the date when the bonds will be sold is not known, the principal amounts of the bond issues and the annual debt service requirements were calculated at three different interest rates: 5%, 6% and 7%.
Net revenues were then compared with debt service requirements for all eight bridges at three different interest rates. The financial consultant concluded that the three western bridge alternatives had positive coverage ratios, in all years after opening:
While the estimates on which these coverage ratios are based, particularly the estimates of construction costs, are not well fixed enough at this time to permit a firm determination of financial feasibility, the coverage ratios seem sufficiently promising at this point in time for the Sands Point-New Rochelle, Glen Cove-Rye, Oyster Bay-Rye bridges to warrant more detailed investigations. If a decision is made to go ahead with the construction of any of these three bridges, we would strongly urge the provision of some form of additional security beyond revenues alone, since such additional security can mean a smaller total bond issue, a lower interest rate, possibly lower tolls, and a better reception of bonds by the investing public.
ECONOMIC STUDIES
Estimates of future population of the New York metropolitan region, for the years 1970 to 2000, were prepared by the economic consultant. Gains in employment, labor force, sales by major industry, and fully taxable valuation of property were also estimated.
Order of magnitude estimates of the impact of Long Island Sound bridges on the economic growth rates of adjacent counties were made. For this purpose, the region was divided into three corridors, since the impacts of individual bridges could not be distinguished from one another with precision. The western corridor would be served by the Sands Point-New Rochelle, Glen Cove or Oyster Bay-Rye bridges; the central corridor by the Port Jefferson-Bridgeport, Shoreham-New Haven or Riverhead-Guilford bridges; the eastern corridor by the East Marion-Old Saybrook or Orient Point-Watch Hill bridges.
By 1980, any one of the three western bridges is expected to generate 22,000 additional jobs on both sides of the Sound; any one of the three central bridges 6,300 additional jobs; and any one of the two eastern bridges 5,700 additional jobs. The economic consultant indicates that the presence of a bridge would have a favorable impact on the economies of counties in the vicinities of the bridgeheads in succeeding decades after 1980, but to a lesser extent.
NATURAL ENVIRONMENT
Studies of potential impact of trans-Sound bridges on the natural environment were made using data from secondary sources checked by field observation. The studies were concerned with possible effects on finfish, shellfish, birds, wetlands, and levels of water pollution. The following conclusions were reached by the environmental consultant:
In Long Island Sound, adverse impact on finfish from the offshore, deepwater bridge spans and piers appears to be negligible. In serving as an artificial reef, the bridge may even attract fish.
The environmental impact of a bridge across Long Island Sound and its approaches is mainly related to the amount and quality of the wetlands and shellfish beds traversed.
Migratory bird fatalities may result from collisions with bridge spans. However, these losses were extremely small when compared to the total population of a species.
Effects of typical pollutants generated by bridge traffic have not been adequately assessed for marine biota. Petrochemical pollutants have adverse and toxic effects. Particulate rubber and asbestos are known to be disease-producing in terrestrial animals, but effects upon marine organisms are unknown.
There do not appear to be species of fish, birds or wildlife threatened by extinction due to construction of a bridge at any of the proposed sites.
The environmental consultant prepared a series of recommendations that would reduce the impact of bridge construction upon the environment.
NOISE IMPACT STUDY
Studies were made to estimate the comparative noise impact cause by traffic on approach roads to alternative bridges. These studies assumed approach expressways at grade on flat terrain; for sleep impact, windows were assumed to be open; no noise control features were assumed to exist.
The following criteria were used:
A rise in the daytime ambient (background) noise level of 6 to 15 dB (decibels) was labeled "some impact," and a rise of more than 15 dB was labeled "considerable impact."
A night-time noise level of 1 to 5 dB over the design goal for sleep was labeled "some impact" and more than 5 dB was labeled "considerable impact."
The nighttime design goal for sleep was set at 40 dB inside residences, with windows open. By comparison, conversation inside a room is 60 dB, an electric typewriter at 10 feet (inside) is 60 dB, and an air conditioning unit at 100 feet is 60 dB. Measurement of the present daytime ambient in Oyster Bay range from 38 to 54 dB with a mean of 45 dB; in Rye they range from 47 to 60 dB with a mean of 50 dB.
The acoustics consultant has stated:
It is recommended that the noise impact of all residences, schools, places of worship, and hospitals within 800 feet be calculated during the detailed design of the bridge, and that the proper noise control be engineered into the highway design to reduce this impact to recommended levels. It should be possible to reduce the noise enough to essentially eliminate the considerable noise impact. It is estimated that the necessary noise control construction would add approximately one-half of one percent to the total construction costs.
Sleep interference by heavy trucks will be considerable for all residences within 200 feet of the approach roads. It is strongly recommended that roadside barriers, as described in the text above, be built to protect such residences.
It is recommended that toll stations be located far enough offshore to allow heavy trucks to complete their acceleration back to highway speeds before reaching the bridgeheads.
AIR POLLUTION
Studies were made of air pollution using available data on present ambient (background) air pollution and estimating the impact of vehicle-produced emissions of pollutants resulting from bridge traffic.
Since wind direction, wind force and other meteorological factors affect air pollution substantially, the dispersion of pollution created by bridge traffic was studied for four cases, three of which were maximum pollution impact cases likely to occur less than six percent of the time as a group.
These studies indicated that the worst pollution would result from tollbooths. Elsewhere, pollution from traffic on the bridge and approach roads even under the most adverse weather conditions would not exceed National Air Quality Standards except on the roadway itself.
For each of the alternative locations, an estimate was given on the number of people living within 150 feet on each side of the approach expressways to the bridge. The air pollution consultant came to the following conclusions:
Within these zones some increase in pollution might be measured, but beyond the confines of these zones, pollution generated by traffic could not be distinguished by measurement from ambient pollution. In most of the area of these zones, the increase in pollution would be insufficient by itself to result in harm to welfare and health, as defined by National Air Quality Standards.
The overall effect of the bridge on air pollution is minor. Some relief will be afforded the New York City area because traffic will bypass the high density region. In addition, overall pollution in the greater New York City-Long Island region will be affected by a slightly higher average vehicle speed. This will reduce carbon monoxide and hydrocarbons, but will increase nitrogen oxides.
The peculiar wind conditions on Long Island make stagnation a slightly more frequent occurrence along the north shore of Long Island, except on the eastern tip, so that pollution during periods of stagnation will be removed only slowly. In northern Nassau County, levels of pollution already exceed desired state and federal standards for particulates, but data on the distribution on other types of pollution is incomplete. Under these conditions, it is very difficult to evaluate the complex question of net regional reductions in air pollution or transfer of pollution from a region that greatly exceeds standards to one where pollution nearly standards or just exceeds standards.
Although the bridge will have little significant effect on overall pollution in the trans-Sound, and most of the time no significant pollution will be observed, there will be times when some localities will observe that a change has occurred. Frequency of such events would be greater on the Long Island side of the bridge.
Since the tollbooth region is a prime source of pollution, its location on the northern end of any bridge is strongly suggested.
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