Comparative Analysis of Level Crossings and Left Turns. Case Study in Bogotá D. C.

Abstract

For many years, mobility in big cities has faced ongoing issues represented in greater delays in travel times. These are more apparent when the route includes main and secondary roads, where intersections play an important role, particularly if a turn to the left is required. The projection of future main roads layout and corresponding intersections implies reviewing the impact that leftturn options, such as direct traffic light turn, turn after a u-turn, loop turn and turn going around the block, among others, would have on travel times. However, it becomes clear that there will be restrictions in some circumstances in which road infrastructure improvements are foreseen for already developed areas, mainly due to the fact that it is difficult to modify land occupied by buildings. Therefore, it is important to understand the impact that it generates in travel times. Out of 31 left turns, analyzed in 10 intersections, the conclusion is that the average time of a direct left turn with a traffic light is 23 seconds, whereas left turns going around the block increase to 219 seconds and left turns after a u-turn take up to 427 seconds. There is a considerable difference among the times, and these values can become critical when projected to a significant flow of vehicles