Development of operational performance models for truck-lane restrictions on freeway corridors

Highways are generally designed to serve a mixed traffic flow that consists of passenger cars, trucks, buses, recreational vehicles, etc. The fact that the impacts of these different vehicle types are not uniform creates problems in highway operations and safety. A common approach to reducing the impacts of truck traffic on freeways has been to restrict trucks to certain lane(s) to minimize the interaction between trucks and other vehicles and to compensate for their differences in operational characteristics. ^ The performance of different truck lane restriction alternatives differs under different traffic and geometric conditions. Thus, a good estimate of the operational performance of different truck lane restriction alternatives under prevailing conditions is needed to help make informed decisions on truck lane restriction alternatives. This study develops operational performance models that can be applied to help identify the most operationally efficient truck lane restriction alternative on a freeway under prevailing conditions. The operational performance measures examined in this study include average speed, throughput, speed difference, and lane changes. Prevailing conditions include number of lanes, interchange density, free-flow speeds, volumes, truck percentages, and ramp volumes. ^ Recognizing the difficulty of collecting sufficient data for an empirical modeling procedure that involves a high number of variables, the simulation approach was used to estimate the performance values for various truck lane restriction alternatives under various scenarios. Both the CORSIM and VISSIM simulation models were examined for their ability to model truck lane restrictions. Due to a major problem found in the CORSIM model for truck lane modeling, the VISSIM model was adopted as the simulator for this study. ^ The VISSIM model was calibrated mainly to replicate the capacity given in the 2000 Highway Capacity Manual (HCM) for various free-flow speeds under the ideal basic freeway section conditions. Non-linear regression models for average speed, throughput, average number of lane changes, and speed difference between the lane groups were developed. Based on the performance models developed, a simple decision procedure was recommended to select the desired truck lane restriction alternative for prevailing conditions. ^

Recreational Foodservice management: A Delphi study of needed competencies

The purpose of this study was to identify the needed competencies of a Recreational Foodservice manager. A three round Delphi method of iteration was used. Delphi is a research method that utilizes iterating rounds to elicit the opinion of a panel of experts regarding a specific subject.^ A nominating committee of 22 industry leaders was consulted to establish a panel of 40 management experts, of which 35 (87.5%) completed all three rounds of the Delphi study.^ Round One of the study identified 17 specific job functions of a Recreational Foodservice manager. The researcher prepared an instrument detailing 60 competencies derived from an analysis of Round One results and distributed it as a Round Two instrument requesting the panel opinion regarding the relative importance of each listed competency on a five point Likert scale.^ The results of Round Two were tabulated and analyzed to ascertain areas of consensus. A Round Three instrument was prepared advising panelists of all areas of consensus, their dissenting opinions, if any, and a request for a revised opinion.^ A final report was prepared listing the 60 competencies and the panel opinion that eight were of highest priority, 29 of above average priority, and 23 of average priority. No item received two other available ratings, below average priority and lowest priority.^ The implications of these findings suggest necessary areas of curriculum development and industry management development to implement professionalism for Recreational Foodservice managers. ^