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CHAPTER 4 TRANSPORTATION 76 • It must be recognized that in long range forecasting small changes in the value of assumed variable, such as daily traffic volume, or peak hour traffic volume may make large changes in the results of the analysis. For example, with each 11% or 12% change in travel demand on the same facility, the level of service changes one letter grade. By comparison, a one percent change in the percentage of the total daily traffic that occurs during the peak hour, say from 10% to 9%, is also equivalent to a letter grade change in the level of service. Other assumed variables have even more effect. For example, the Metropolitan Council has assumed that travel demand in the year 2000 will be 3.30 trips per person, as opposed to 2.72 trips per person today. This is an expansion of 21% and may be highly questionable in view of the uncertainties about future gasoline supplies and prices. This assumption, however, is fundamental to the whole forecasting process. The obvious conclusion is that the forecasting and analysis methods employed are adequate for a gross examination, but cannot provide the reader with a complete sense of ease where a precise answer is needed. The complexity of factors involved, the uncertainty of the future, and the inherent variability and adaptability of traffic suggest only that the analysis results can be used as the best available guide, subject to mature reflection and judgement. Annual monitoring of traffic volume changes, particularly at potential trouble spots, will be needed to detect emerging problems. • FINDINGS: PRINCIPAL ARTERIALS Since New Brighton is a nearly fully developed community, the projected infill and redevelopment activity within the City would have a minimal impact on the Metropolitan Transportation System. However, the Metropolitan Council identifies New Brighton as being "a community in or near a highly congested transportation corridor." Therefore, though New Brighton itself would not contribute heavily to the future traffic levels of I-35W and I-694, the Metropolitan Council projected increase in traffic volumes along these regional corridors causes New Brighton to recognize the need for a mixture of carrying capacity improvements and traffic management strategies for I-35W and I-694. These improvements and strategies include High Occupancy Vehicle Lanes (HOV's), HOV bypass ramps, and the metering of ramps. The Metropolitan Council recommends that traffic flow onto the metropolitan highway system be regulated, as soon as possible, by metering entrance ramps in the western two-thirds of the Metropolitan Area. Metering will increase roadway capacity, improve safety and protect the system from traffic generated by development that exceeds capacity. It may, however, reduce the capacity of individual entrance ramps. Typically, the capacity of a metered ramp lane is about 400 to 800 vehicles per hour. In some cases of extreme congestion, the capacity of a metered ramp could be as low as 200 vehicles per hour. Ramps with HOV bypass ramps for the exclusive use of car pools, van • pools and buses will have additional capacity, and will encourage use of high-occupancy vehicles that can bypass meters.