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Economic analysis of mobility improvements
Published in Zongzhi Li, Transportation Asset Management, 2018
Grade separations: Intersections that handle high volumes of vehicular and pedestrian traffic (and in some cases rail traffic) limit the capacity of the approaching roads. Grade-separating these points of conflict allows uninterrupted traffic flow while also eliminating the safety threat posed by crossing traffic. Three primary roadway improvement objectives are accomplished using grade-separated intersections: (i) increased capacity and uninterrupted flow; (ii) increased safety; and (iii) reduced auto-train conflicts and delays. Grade separation can be implemented for high-volume roadway intersections or highway-railroad crossings. Grade-separated intersections are expensive to build, thus they should be used only when other techniques such as signal timing and lane additions are unsuccessful in reducing congestion to an acceptable level or were impossible due to external constraints. Grade separation works well when one or more directions continue to experience heavy traffic and high congestion even after other methods have been exhausted.
Identifying the most suitable road crossing infrastructure based on estimated delay to pedestrians and vehicle users
Published in Transportation Letters, 2018
Mihir Prajapati, Mukti Advani, Purnima Parida
Two broad categories of road crossing facilities could be (1) at-grade and (2) grade-separated facilities. At-grade pedestrian crossings are those where the pedestrians cross the carriageway at the same level as that of vehicular movement and it may or may not be separated by time. Grade-separated crossings are those where the pedestrians are required to cross the carriageway at the level different from that vehicular movement. Thus, the latter may be in the form of a pedestrian subway or a FOB across the road. Further, when movements of pedestrians has been controlled by at-grade designs, automatic signals, users’ controlled signals, sensors, etcetera, have been categorized as controlled crossings. This may be applied at intersections or at mid-blocks.