Transportation systems provide a means for moving people and the goods from which they are spatially separated. Of the two means of surface transportation, the motorized mode is used extensively for utilitarian travel in developed countries. The increasing reliance on motorized travel has contributed to increased traffic congestion, air pollution, and greenhouse emissions. Non-motorized travel has recently received significant attention as a means to reduce congestion and environmental problems and improve human health. However, non-motorized modeling is generally underdeveloped. This study investigated some changes in non-motorized and total travel and the characteristics of the traveling public in 1990, 1995, 2001, and 2009 using a national travel survey. The study also investigated the temporal transferability of linear-regression trip generation models for non-motorized and total travel under such changes. High-income households made fewer non-motorized trips in 1990 and 1995 compared to 2001 and 2009. Persons aged 50 and over showed an increased demand for non-motorized travel, whereas children aged 0 - 15 showed a decreasing preference for non-motorized travel over time. Regarding temporal stability, only the coefficient for single-adult households with no children was stable across all of the analysis years. For both non-motorized and total travel, most model parameter estimates were stable short term but not long term. In general, the total travel models transferred better than non-motorized models, both short term and long term. Despite not finding universal stability in model parameter estimates, the models were marginally able to replicate travel in 2009 relative to the locally estimated 2009 model

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Article Info AbstractKeywords: RFID Speed Reader TagThis study investigates the effect of speed, tag and reader location, vehicle speed, and over-shadowing on RFID performance. The study tested two reader/antenna heights and three tag locations. Three vehicle speeds were tested for each tag location including the simultaneous placement of RFID tags on the vehicle. The study results show, with tags individually placed on the vehicle, the appropriate position for a tag is on the vehicle windshield, and the reader/antenna set at 7ft above the ground on a signpost. Placing multiple tags on the vehicle simultaneously improved the signal strength and detection rates. Vehicle speed had a negative effect on tag detection rate; that is, at higher vehicle speeds the detection rate decreased. With respect to horizontal distance between the reader and the tag, the results show that, the closer the tag and reader are to each other the higher the signal strength and so is the detection rate.

Linear assets including roads, pipelines, and railroad tracks are defined assets whose lengths play a critical role in their maintenance. Linear assets, along with their features, which include traffic lights, number of lanes, speed limits, guardrails, and highway billboards, are hard to physically access and, therefore, update inventory information files that were previously captured. To address this problem, some transportation agencies are investigating technologies that will assist in solving this asset inventory problem. The primary focus of this paper is to evaluate the feasibility of using radiofrequency identification (RFID) technology as a means of gathering, verifying, and storing information for linear assets. The study investigates confluence factors that affect the performance of RFID. The factors investigated include driving speed and tag location on signposts, delineators, and guardrails. The results indicate that for the three vehicle speeds tested (10 mph, 20 mph, 30 mph), tag readability decreased with an increase in speed.

The discharge of a thermal energy storage system, which is modeled as a one-dimensional slab of pure, molten material, is investigated semi-analytically. With the molten material initially at its fusion temperature, double-sided freezing is induced from convective and radiative cooling on one side, and convective cooling on the other, resulting in two coalescing freeze fronts. The effects of cyclic solar flux, cyclic sky temperature, and cyclic fluid temperature on the freeze front progression of one side of the slab and freeze time for entire slab are examined. On applying the quasi-steady approximation for the temperature distribution in each developing solid region, a pseudo-transcendental equation for the temperature of the surface exposed to convection and radiation is derived and solved at discrete time intervals by the Newton-Raphson method. Excellent agreement is obtained with previously published results for freezing caused by convective and radiative cooling only on one side, while the other side remains adiabatic. It is shown that low frequency (high period) cycling of the sky and fluid one temperatures increase the freeze time up to greater than 40% when the solar flux profile is constant or non-cyclic and when surface radiative heat loss is neglected.