This paper studies the effects of queue formation in the bottlenecks at off-RAMPs on the capacity of the freeways. Six expressway exit-RAMPs throughout the city of Tehran, Iran were selected and their traffic flows were observed in thirty-minute intervals during which the queue formation and queue elimination occurred. Assuming that in the absence of the queue, the traffic flow is in its normal state, the changes in the volume of through vehicles has been modeled as an average estimator of the change in the expressway capacity.The developed models prove that the changes in freeway capacity are due to queue formation at the off-RAMP sections. However, the estimated figures are different from those obtained from the theory of freeway capacity. The conclusion is that lane blockage is only one of many factors that affect the freeway capacity while the queue forms. Since it is not possible to quantify all those factors individually, the resulting models are macroscopic estimates of the phenomenon.

Background: The prevalence of obesity is increasing worldwide, and anesthesiologists are facing challenges in the airway management of such patients. Excessive adipose tissue infl uences pharyngeal spaces and aff ects the laryngoscopic grade. Standard RAMP positioning is time-consuming and diffi cult to prepare, and requires expensive equipment. Objectives: The aim of this study was to compare the standard RAMP position with the proposed low-cost and easily accessible modifi ed RAMP position in laryngoscopic view during the intubation of patients with morbid obesity. Methods: In this single-blind clinical trial, 84 patients candidate for bariatric surgery at Rasoul Akram Hospital in 2020 were assigned to the rapid airway management positioner (RAMP) (R) and new modifi ed RAMP (MR) groups by the block randomization method. The laryngoscopic view of the glottis based on the Cormack-Lehane scale, ventilation quality, duration of intubation, intubation attempts, oxygen saturation at the end of intubation, and the need for backward, upward, rightward pressure (BURP) maneuver for successful intubation were recorded. Normal distribution tests and Mann-Whitney and Kruskal-Wallis tests were used to analyze the data. Results: The results showed no signifi cant diff erences between the two groups regarding ventilation score, laryngoscopy grade, number of intubation attempts, duration of intubation, and the need for BURP maneuvers during intubation (P > 0. 05). Conclusions: The two methods are not signifi cantly diff erent, and the new modifi ed RAMP position can be used with more ease and availability and less cost.