Optimization Model of Transit Route Fleet Size Considering Multi Vehicle Type

This paper proposes a bus line capacity optimization design model considering the scale of multiple vehicles, which is achieved by minimizing system operating costs and user costs. The proposed model takes into account the difference of passenger demand in different periods, and can get the optimal headway and delivery and reserve plan. In order to prove that the method can effectively minimize the cost, we solved a numerical example and compared the cost of the method in multi-transit model planning. Furthermore, the optimization results show that the total costs (TC) were reduced by 14.48%. Among them, the user costs (UC) decreased by 30.38% and the operator costs (OC) increased by 4.18%. Sensitivity analyses are presented to verify the validity of the model. The analysis results show that multi size bus optimization can reduce the total cost, especially the user cost in a certain cost weight interval. Besides this, the cost weight which reflects the passenger volume and waiting time value, optional bus size and cross-section passenger volume all affect vehicle scheme and system cost.

Emergence Time Phasing for the Potential New Airports in the Middle District of Iraq

With the growing demand for air transportation and limited capacity at Baghdad International airport (BIAP), there is a need to increase the capacity of airport systems in the middle district of Iraq. The increased use of secondary airports has been and is expected to be one of the key mechanisms by which future demand is met in congested metropolitan areas. This paper analyzed the factors influencing the emergence of secondary airports in the Iraqi middle district and the dynamics of multi-airport systems. A system dynamics model was developed to simulate the relationship between the core airport in Baghdad and three potential secondary airports, one in each adjacent governorate. The model takes under consideration such characteristics as; capacity, location, proximity to populated communities, and ground transportation services for each airport. the main outcomes of this model are; the passenger's persuasion in an airport, which reflects their propensity to use this particular airport, and the predicted number of annual passengers in each airport. The system dynamics model was consulted twice. The outcomes of the first run facilitated the economic analyses of the secondary airports on which the sequence of the airports emergence was determined, and it also showed that the new airport feasibility is highly affected by the location, due to the influence on the road user cost for passengers, in addition to the capital expenses. The second run of the model helped in predicting the time schedule and interval between an airport emergence and the other. If the new airports have an equal capacity of one million passenger per year, the expected timing for the emergence is in 2023, 2027, and 2032 for the airports in Balad, Habbaniyah, and Baquba respectively.

Constructing Divisia Monetary Aggregates for Singapore

Since Barnett derived the user cost price of money, the economic theory of monetary services aggregation has been developed and extended into a field of its own with solid foundations in microeconomic theory. Divisia monetary aggregates have repeatedly been shown to be strictly preferable to their simple sum counterparts, which have no competent foundations in microeconomic aggregation or index number theory. However, most central banks in the world, including that of Singapore, the Monetary Authority of Singapore (MAS), still report their monetary aggregates as simple summations. Recent macroeconomic research about Singapore tends to focus on exchange rates as a monetary policy target but ignores the aggregate quantity of money. Is that because quantities of money are irrelevant to economic activity? To examine the role of monetary quantities as potential monetary instruments, indicators, or targets and their relevance to predicting real economic activity in Singapore, this paper applies the user cost of money formula and the recently developed credit-card-augmented Divisia monetary aggregates formula to construct monetary services indexes for Singapore. We produce those state-of-the-art monetary services indexes from Jan 1991 to Mar 2021. We see that Divisia measures behave differently from simple sum measures in the period before the year 2000, while interest rates were high. Credit-card-augmented Divisia monetary services move closely with the conventional Divisia monetary aggregates, since the volume of credit card transactions in Singapore is relatively small compared with other monetary service assets. In future work, we plan to use our data to explore central bank policy in Singapore and to propose improvements in that policy. By making our data available to the public, we encourage others to do the same.

Regression Models of Road User Cost Prediction for Highway Maintenance and Rehabilitation for Life Cycle Planning in California

Road user costs (RUCs) have been studied for the past few decades and still need to be considered to obtain a complete picture of the impact of road construction, maintenance, and rehabilitation. RUCs comprise delay costs (value of time), vehicle operating costs, and accident costs. Federal Highway Administration’s Life Cycle Cost Analysis software RealCost has been adapted, customized, and enhanced by California’s Department of Transportation (Caltrans) for California’s traffic patterns and maintenance practices in RealCostCA. However, the different types of roadways, traffic distributions, and work zone types have not been analyzed. In addition, RealCostCA works for selecting the most cost-effective pavement alternative under a project-specific basis and does not address network-level integration of RUCs. This study aimed to build easy-to-use look-up tables to obtain RUCs for a factorial of different work zone and traffic conditions. Different combinations of three roadway types (freeways, state highways, county roads), four representative hourly traffic distributions, three typical work zone closures (10-hour nighttime, 24-hour, 55-hour weekend closure), the numbers of lanes available in normal conditions (no work zone), and the numbers of lanes open during work zones were included in the factorial to calculate RUCs for specific traffic demand ranges at an interval of 5,000 vehicles per day per direction. The data obtained were subsequently used to combine into mixed regression models. These models enable calculation of RUC at any traffic level customized to the location of the project. Future work will be undertaken to combine the models into Caltrans’ network-level pavement management system.

HOUSE PRICES, RENTAL COSTS, AND MORTGAGE INTEREST RATES

Studies have typically adopted the price-rent ratio to determine whether housing exuberance exists and the periods of imbalance between house prices and rental costs. Using the price-rent ratio to conduct tests without considering the effects of mortgage interest rates on user costs may overestimate episodes of exuberance. This study uses data of the overall housing market and those of 10 major metropolitan statistical areas (MSAs) in the United States from 1979Q1 to 2018Q1 to evaluate whether housing exuberance exists in the markets; the results indicate that all the MSAs experienced episodes of exuberance at different times and the overall housing U.S. market was overheated from 1998Q2 to 2007Q3. By considering mortgage rates and using the user-cost-rent ratio, we further determine that short-term housing exuberance emerged in only two MSAs, Los Angeles and Miami, in 2006Q2, which was followed by immediate corrections. Thus, the research results of this study signify that only use the price-rent ratio to determine whether or not rational housing tenure choice made by traders exists is not sufficient. This study provides evidence showing that the method incorporating mortgage interest rates tends to obtain an equilibrium relationship between the rental and housing markets, indicating interest rates play an important role in housing tenure choice.

A Comprehensive Life-Cycle Cost Analysis Approach Developed for Steel Bridge Deck Pavement Schemes

This study aims to evaluate the economy of a steel bridge deck pavement scheme (SBDPS) using a comprehensive life-cycle cost (LCC) analysis approach. The SBDPS are divided into the “epoxy asphalt concrete system”(EA system) and“ Gussasphalt concrete system”(GA system) according to the difference in the material in the lower layer of the SBDPS. A targeted LCC checklist, including manager cost and user cost was proposed, and a Markov-based approach was applied to establish a life-cycle performance model with clear probability characteristics for SBDPS. Representative traffic conditions were designed using a uniform design method, and the LCC of SBDPS under representative traffic conditions and different credibility (construction quality as a random factor) was compared. The reliability of the LCC analysis approach was verified based on the uncertainty analysis method. Based on an expert-scoring approach, a user cost weight was obtained to ensure it is considered reasonably in the LCC analysis. Compared with the cumulative traffic volume, the cumulative equivalent single axle loads (CESAL) have a closer relationship with the LCC. The GA system has better LCC when the CESAL is less, while the EA system is just the opposite. The breaking point of CESAL for the LCC of the EA system and the GA system is 15 million times. The LCC analysis of SBDPS should consider the influence of random factors such as construction quality. The comprehensive LCC analysis approach in this paper can provide suggestions for bridge-management departments to make a reasonable selection on SBDPS.