Incentive Design and Profit Sharing in Multi-modal Transportation Network

We consider the situation where multiple transportation service providers cooperate to offer an integrated multi-modal platform to enhance the convenience to the passengers through ease in multi-modal journey planning, payment, and first and last mile connectivity. This market structure allows the multi-modal platform to coordinate profits across modes and also provide incentives to the passengers. Accordingly, in this paper, we use cooperative game theory coupled with the hyperpath-based stochastic user equilibrium framework to study such a market. We assume that the platform sets incentive (subsidy or tax) along every edge in the transportation network. We derive the continuity and monotonicity properties of the equilibrium flow with respect to the incentives along every edge. The optimal incentives that maximize the profit of the platform are obtained through a two time-scale stochastic approximation algorithm. We use the asymmetric Nash bargaining solution to design a fair profit sharing scheme among the service providers. We show that the profit for each service provider increases after cooperation on such a platform. We complement the theoretical results through two numerical simulations

Effectiveness of intermittent preventive treatment in pregnancy with sulphadoxine-pyrimethamine (IPTp-SP) in Ghana.

INTRODUCTION: Ghana adopted the revised WHO recommendation on intermittent preventive treatment in pregnancy using sulfadoxine-pyrimethamine (IPTp-SP) in 2012. This study has assessed the effectiveness and safety of this policy in Ghana. METHODS: A total of 1926 pregnant women enrolled at antenatal care (ANC) clinics were assessed for birth outcomes at delivery, and placental histology results for malaria infection were obtained from 1642 participants. Association of reduced placental or peripheral malaria, anaemia and low birth weight (LBW) in women who received ≥4 IPTp-SP doses compared with 3 or ≤2 doses was determined by logistic regression analysis. RESULTS: Among the 1926 participants, 5.3% (103), 19.2% (369), 33.2% (640) and 42.3% (817) of women had received ≤1, 2, 3 or ≥4 doses, respectively. There was no difference in risk of active placental malaria (PM) infection in women who received 3 doses compared with ≥4 doses (adjusted OR (aOR) 1.00, 95% CI 0.47 to 2.14). The risk of overall PM infection was 1.63 (95% CI 1.07 to 2.48) in 2 dose group and 1.06 (95% CI 0.72 to 1.57) in 3 dose group compared with ≥4 dose group. The risk of LBW was 1.55 (95% CI 0.97 to 2.47) and 1.06 (95% CI 0.68 to 1.65) for 2 and 3 dose groups, respectively, compared with the ≥4 dose group. Jaundice in babies was present in 0.16%, and 0% for women who received ≥4 doses of SP. CONCLUSION: There was no difference in the risk of PM, LBW or maternal anaemia among women receiving 3 doses compared with ≥4 doses. Receiving ≥3 IPTp-SP doses during pregnancy was associated with a lower risk of overall PM infection compared with 2 doses. As there are no safety concerns, monthly administration of IPTp-SP offers a more practical opportunity for pregnant women to receive ≥3 doses during pregnancy

Ground tire rubber as a component material in concrete mixtures for paving concrete

The management of solid waste is a major environmental concern in the United States. Waste tire rubber forms a major part of this problem and a rather severe one since tire rubbers are not biodegradable hence its disposal into landfills are of great concern. This research primarily focused on finding the best way of producing paving concrete with the use of ground tire rubber as a component material. Tests on rubber concrete were performed in two stages. Preliminary tests were performed using both 40-mesh GTR and 3/8-inch rubber chips (RC) to replace fine aggregates and coarse aggregates respectively by weight in the concrete mix. This stage of testing considered zero to 40 percent GTR replacement of fine aggregates by weight at 10 percent increment and for zero to 30 percent RC replacement of coarse aggregates by weight at 10 percent increment. Observations from this stage guided the formulation of a second and final stage of testing which involved only zero to 20 percent GTR replacement of fine aggregate by weight at 5 percent increment. The mix design for this stage involved the use of water reducers, air-entrainer and fly-ash. In addition to concrete mechanical property tests, coefficient of thermal expansion (CTE), plastic shrinkage and drying (free) shrinkage tests were also conducted. Results from preliminary tests indicated that GTR and RC concrete specimens were of relatively low strength, improved toughness and showed more elasticity when compared to normal concrete specimens. The final stage of laboratory testing however showed improved strength characteristics, with the initial observations of improved toughness and low modulus of elasticity still evident. Coefficient of thermal expansion (CTE) test results did not show significant difference between mix-types, with the range of results falling within the typical limit for normal concrete. Plastic shrinkage test results showed that the inclusion of GTR helped in reducing plastic shrinkage cracks in concrete. Preliminary results at the second stage testing on drying shrinkage using 10% GTR concrete indicated a reduction in free shrinkage when compared to the control specimens

Towards transit equity in Detroit: An assessment of microtransit and its impact on employment accessibility

Several studies cite great potential for microtransit services to improve transportation equity by providing disadvantaged communities with a more flexible and reliable option relative to traditional fixed route transit. However, few have attempted to forecast these equity benefits. This study seeks to contribute to the ongoing discussion by exploring potential equity impacts of a microtransit service in Metropolitan Detroit. Using a logsum accessibility measure calculated from a regional travel demand model, we simulate accessibility changes due to a hypothetical regional microtransit service and demonstrate a regional transportation equity analysis using a typical regional travel demand model. Our results show that accessibility gains would be slightly higher for lower income communities (17% increase compared with 13% for high income) and transit-dependent households (21% compared with 15% for car-owning households). Further, we find that Microtransit may help to reduce gaps in accessibility between disadvantaged and more advantaged traveler groups

Demand responsive transit simulation of Wayne County, Michigan

Demand responsive transit (DRT) can provide an alternative to private cars and complement existing public transport services. However, the successful implementation of DRT services remains a challenge as both researchers and policy makers can struggle to determine what sorts of places or cities are suitable for it. Research into car-dependent cities with poor transit accessibility is sparse. This study addresses this problem, investigating the potential of DRT service in Wayne County, U.S.A., whose dominant travel mode is private car. Using an agent-based approach, DRT is simulated as a new mobility option for this region, thereby providing insights into its impact on operational, user, and system-level performance indicators. DRT scenarios are tested for different fleet sizes, vehicle occupancy, and cost policies. The results show that a DRT service in Wayne County has a certain potential, especially to increase the mobility of lower-income individuals. However, introducing the service may slightly increase the overall vehicle kilometers traveled. Specific changes in service characteristics, like service area, pricing structure, or preemptive relocation of vehicles, might be needed to fully realize the potential of pooling riders in the proposed DRT service. The authors hope that this study serves as a starting point for understanding the impacts and potential benefits of DRT in Wayne County and similar low-density and car-dependent urban areas, as well as the service parameters needed for its successful implementation.ISSN:0361-1981ISSN:2169-405

Demand responsive transit simulation of Wayne County, Michigan

Demand responsive transit (DRT) can provide an alternative to private cars and complement existing public transport services. However, the successful implementation of DRT services remains a challenge as both researchers and policy makers can struggle to determine what sorts of places or cities are suitable for it. Research into car-dependent cities with poor transit accessibility is sparse. This study addresses this problem, investigating the potential of DRT service in Wayne County, U.S.A., whose dominant travel mode is private car. Using an agent-based approach, DRT is simulated as a new mobility option for this region, thereby providing insights into its impact on operational, user, and system-level performance indicators. DRT scenarios are tested for different fleet sizes, vehicle occupancy, and cost policies. The results show that a DRT service in Wayne County has a certain potential, especially to increase the mobility of lower-income individuals. However, introducing the service may slightly increase the overall vehicle kilometers traveled. Specific changes in service characteristics, like service area, pricing structure, or preemptive relocation of vehicles, might be needed to fully realize the potential of pooling riders in the proposed DRT service. The authors hope that this study serves as a starting point for understanding the impacts and potential benefits of DRT in Wayne County and similar low-density and car-dependent urban areas, as well as the service parameters needed for its successful implementation.ISSN:0361-1981ISSN:2169-405

Driver Behavior at a Freeway Merge to Mixed Traffic of Conventional and Connected Autonomous Vehicles

Freeway merge ramps serve as one of the most challenging areas in traffic operations. This paper primarily focuses on creating a mixed traffic of conventional and connected/autonomous vehicles (CAVs) on freeways, and capturing driver behaviors both for the merging vehicle on the ramp and the freeway vehicles. The mixed distribution of vehicle headways of the freeway vehicles, developed based on various market penetration rates of the CAVs, was used to randomly generate vehicles through Monte Carlo simulation, and assigned as headways in a driving simulator. Based on perception, young drivers on the merge ramp were observed to choose critical headway gaps of 2.9 s, 1.8 s, and 1.7 s for freeway traffic of 0%, 50%, 75% penetration rates, respectively. For similar CAV penetration rates, the critical gaps observed for elderly drivers were 3.5 s, 2.0 s, and 1.9 s, respectively. When actually driving in the simulator, for the scenarios of 0% CAVs and 50% CAVs on the freeway, the values of average headway gaps accepted by young drivers were estimated as 2.36 s and 1.53 s, respectively. For the elderly drivers driving the simulator, the average headway gap values accepted were estimated as 2.72 s and 1.55 s, respectively, in the 0% and 50% penetration rates on the freeway traffic. Analyses of the speed profiles of the vehicles showed the effects of the acceleration/deceleration of merging vehicles, for both young and older drivers, on the freeway vehicles, including a few cases of collision. Overall, it was observed that the subject drivers accepted shorter headway gaps for increased CAV penetration levels