Where young, elderly, and/or persons with physical or visual disabilities need special consideration, the pedestrians and their crossing times may be classified by general observation. Pedestrian volume counts on each crosswalk during the same periods as the vehicular counts in Item B and during hours of highest pedestrian volume. Vehicular volumes for each traffic movement from each approach, classified by vehicle type (heavy trucks, passenger cars and light trucks, public-transit vehicles, and, in some locations, bicycles), during each 15-minute period of the 2 hours in the morning and 2 hours in the afternoon during which total traffic entering the intersection is greatest. It is desirable that the hours selected contain the greatest percentage of the 24-hour traffic volume. The number of vehicles entering the intersection in each hour from each approach during 12 hours of an average day. Engineering study data may include the following: A. When projected volumes are used to warrant a traffic signal, the warrants is to be significantly exceeded to provide for reasonable error in the traffic projections used for the development. The consultant shall use the principles of the Institute of Transportation Engineers Trip Generation, latest edition when determining the projected volumes at the entrances in question. The projections are to be part of a formal traffic impact study performed by a traffic engineering consultant. Great care is to be taken evaluating an intersection for traffic signals when projections are used. Projected volumes, if properly determined, can be accurate gauges of the expected traffic. Many times developers will submit projected volumes to justify the installation of a traffic signal. Signal Control or Free Right Without Adequate ApproachĪt a location that is under development or construction and where it is not possible to obtain a traffic count that would represent future traffic conditions, hourly volumes should be estimated as part of an engineering study for comparison with traffic signal warrants. Percent Right Turn Used in Warrant Analysis Right Turn Percentage (Right Turn Volume/Total Approach Volume) Table 902.3.1 Number of Right Turns to Include in a Warrant Analysis Proposed Right Turn Condition The following is a guide for determining the number of right turns to include in a warrant analysis. If right turns on red are prohibited for an approach, the full right-turning volume is to be considered in warrant analysis. To account for this effect in warrant analysis, the percentage of right turns used in warrant analysis is to be reduced as the right turn percentage of total approach volume increases. As the right turn percentage of total approach volume increases, the benefit of signalization decreases. ![]() ![]() Right turns are typically allowed on red and right turns only require gaps in one or two conflicting movements. Where the right turns are under signal control or where there is a free right with no adequate approach lane, right turns may be included in warrant analysis. In such cases, the right-turning volumes for the affected approaches are not to be included in the warrant evaluation. If a separate channelized or 'free' right with an adequate approach lane is available or proposed, the benefits of a traffic signal in accomplishing this movement are minimal. Engineering judgment should be used to determine what, if any, portion of the right-turn traffic is subtracted from the minor-street traffic count when evaluating the count against the signal warrants listed above. The engineering study should consider the effects of the right-turn vehicles from the minor-street approaches.
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