The volume of earthwork for nearly all highway construction projects is determined during the design stage. This is done for a two-fold reason. By using the excavation and embankment yardage figures, the project may, by adjusting grades, be brought to earthwork balance. If it is not feasible to balance the project, a yardage figure, either waste or borrow is arrived at. The second reason for obtaining this yardage figure is its use as a contract bid item. The yardage quantities arrived at in design may or may not be used as final pay quantities.
An accepted method for obtaining earthwork volumes in the past has been the cross-section method. The basis of this system is the average end area. There is no reason to elaborate on this method here because I feel sure that each reader is familiar with the details of obtaining earthwork quantities by the cross-section method.
In the last few years a new idea for arriving at earthwork quantities has been introduced into the field of highway design and construction. This comparatively new procedure for highway earthwork volumes is frequently referred to as the "finished contour method . The purpose of this manual and subsequent instruction classes is to place this new system at your disposal.
We will first introduce some basic aerial photogrammetry and terminology. We will touch lightly on ground control and then we shall develop step by step the finished contour system.
Statistics show train-vehicle collisions are not altogether uncommon occurrences even in Minnesota, with its 5,400 public and similar number of private rail-highway grade crossings. Inevitably, motorists are the losers: In 1983, one out of every 12 rail-highway grade crossing accidents resulted in a fatality.
Railroads are an undeniable asset to the economic health and competitiveness of the state. But it appears they are not taken as seriously by motorists, who have shown themselves to be either ignorant of or unconcerned by a locomotive's power, speed and inability to stop on short notice. Of all train-vehicle collisions in Minnesota in 1990, human error was a factor 94 percent of the time.
In those cases in which motorists are unaware of an approaching train, improved signaling and visibility at the crossing will help. In those cases in which motorists naively think they can beat the train across the tracks, education is the key.
Both are major focuses of this study. Briefly, considering the state's limited resources, it makes sense to insert rail-highway grade crossing safety into all existing driver-education programs (especially those geared to teenage and over-55 drivers, who are especially at risk). Likewise, it is logical to target public information efforts, including those for school-age groups, along the main rail lines, where contact with trains is most likely to occur. Another suggestion is to develop a new railroad-safety brochure to distribute
wherever other automobile safety tips are available.
