What transportation modeling needs from a GIS: a conceptual framework

Both the geographic information system (GIS) and transportation modeling environments have seen continually developing analytic concepts and techniques. However, these developments have seldom resulted in the integration of GISs and transportation models. This paper explores the potential inherent in merging of these environments through a systematic investigation of the fundamental basis of integration. To do this, the traditional four step transportation modeling process is extended to include input and output steps. We then define functional components for GIS data handling — data management, manipulation, and analysis. The steps of modeling are matched against the list of GIS data handling functions within a matrix‐based framework. GIS functions that enhance a land‐use based urban transportation modeling process are then categorized. Conclusions are drawn and directions for future developments are discussed.     

Longitudinal control of a vehicle

Generally applicable formulae for the gain constants in a proportional plus integral controller required for stable control of the speed of any vehicle in terms of natural frequency, damping ratio, vehicle mass, and thruster time constant are derived. An example, based on a simulation of the controller and vehicle, is given. The theory shows that only speed and position feedback are needed. Acceleration feedback is unnecessary.     

The shape of MaaS: The potential for MaaS Lite

Mobility as a Service (MaaS) is about improving mobility for people. Since Gothenburg piloted the first multi-modal Mobility as a Service (MaaS) scheme from 2012, there have been many further attempts at introducing connected and bundled services globally, invariably provided as a mobile app and a single, simple ticketing interface. As in any emerging paradigm, the varying flavour, or ‘shapes’ of MaaS that are piloted reflect the search for a sustainable business model and connectivity between transport operators at varying levels that includes risk reallocation and data sharing. The varying levels of success of MaaS and Mobility on Demand (MOD) lead the authors to propose MaaS Lite, which reflects an incremental approach to MaaS based on a simpler organisational arrangement that does not depend upon the introduction of a Mobility Operator as a new player. MaaS Lite also recognises that most trips are not complex at all, often based on one or two connected mechanised modes that meets highly local needs, including FMLM service connectivity.Overall, MaaS is not a ‘one size fits all’ solution for all regions but the benefits of the highly targeted MaaS Lite could realise early public benefits as a first step in the development of a multi-phased ‘services road map’ that evolves towards the implementation of multi-modal, region-wide operationally integrated MaaS. Case studies in Hong Kong and Brisbane demonstrate the merits of MaaS Lite in these two contrasting environments having different regulatory regimes, population densities and levels of private car ownership.     

A Dynamical Analysis of a Towed Two-Wheel Trailer1

The towed trailer method for skid resistance measurements is a practical one for characterizing the friction characteristics of highway pavements, and has been standardized by the ASTM 11). Numerous papers have been published about the improvement of equipment and field-testing techniques but little has been done toward a theoretical explanation.

This paper presents a mathematical model of the trailer which includes roll, pitch, and vertical motion. The skid resistance calculated by using this model gives an excellent check on the standard ASTM skid number formula. The response time and damping effect after locking one test wheel can be clearly seen in this model. Possible effects of the dimensions of trailer, stiffness of suspension system, tire pressure, etc. to skid resistance can also be examined.     

Synchronous or clear-path control in personal rapid transit systems

This note derives an equation for the ratio of the maximum possible station flow to average line flow in a personal rapid transit or dual-mode system using fully synchronous control. It is shown that such a system is impractical except in very small networks.     

Optimization of transit-system characteristics

The transit industry is facing declining ridership and increasing costs with with no apparent end in sight. This paper takes the view that totally new solutions are needed. The approach is to examine the equation for total cost of a transit system per passenger-mile to determine how to configure a new system to minimize this quantity. Term-by-term analysis leads to derivation of a consistent set of optimum characteristics. Guideway costs are minimized by distributing the load in very small capsules. The fleet cost is minimized by increasing the average speed without increasing the cruising speed by use of off-line stations, which in turn minimize energy use by permitting nonstop trips. Maintenance costs are minimized by designing a very light-weight, automated vehicle with very few moving parts. While this general configuration has been known for several decades, it has not been generally recognized that it can be derived by minimization of system costs, and that cost minimization is obtained simultaneously with service maximization. While a great deal of controversy surrounded this concept a decade ago, advances in technology make it fully practical now.