Household travel survey data are crucial in regional travel demand analysis. However, good quality data are not always available owing to financial constraints, privacy concerns, poorly designed sampling schemes, and/or low response rates. Thus, various data synthesis techniques have been proposed in the past. In this paper, we identify the limitations of the existing data updating/synthesis methods and propose a two-level random coefficient model to synthesis household travel characteristics across geographic areas. Then the two-level structure was applied to the sampled households in the 2001 National Household Travel Survey across (consolidated) metropolitan statistical areas of various population sizes. One particular travel characteristic, journey to work vehicle trip rate, is investigated. The study findings confirm the effect of neighborhood (defined at the census tract level) attributes (e.g., intersection density, average auto mobile work trip travel time) on household number of journey to work vehicle trips. This effect is significant on the urban households of study, whereas the suburban counterparts across the country do not seem to be affected by their living environments after controlling for neighborhood type. In general, the two-level structure is shown statistically superior to the one level.

Access connections and signalized intersections within the functional area of an interchange can adversely impact safety and operations at the interchange crossroad and on the freeway, and can cause the interchange to fail prematurely. Standard practice is to acquire a minimum of $90\mathrm{m}$ $\left(300\mathrm{ft}\right)$ of limited access right-of-way beyond the end of the acceleration/deceleration lanes for rural interchanges and $30\mathrm{m}$ $\left(100\mathrm{ft}\right)$ in urban areas. Although the safety and operational benefits of managing access in freeway interchange influence areas are clear, the cost effectiveness of purchasing access rights at the time of interchange construction has not been established through national or state-level research. The primary objective of this study was to assess the relative costs and benefits of purchasing additional limited access right-of-way at the time of construction in lieu of retrofitting interchange areas after functional failure. The study methodology included the following basic steps: (1) traffic operations analysis of the study interchange with varying configurations of signalized access spacing using CORSIM; (2) safety analysis of a sample of Florida interchanges with varied access spacing; and (3) cost/benefit analysis of acquiring varying amounts of limited access right-of-way. This study indicates that the long-term safety, operation, and fiscal benefits of purchasing additional limited access right-of-way at interchange areas greatly exceed the initial costs. The findings suggest that state transportation agencies and the traveling public may benefit greatly by an increase in the amount of limited access right-of-way at interchange areas to a minimum of $180\mathrm{m}$ $\left(600\mathrm{ft}\right)$ and a desirable $400\mathrm{m}$ $\left(\mathrm{1,320}\mathrm{ft}\right)$ .

The paper presents a methodological framework that integrates different data-driven techniques in order to detect the different traffic flow regimes (free flow, congested conditions, and so on) observed in signalized arterials as well as the manner traffic flow shifts from one regime to another (transitions). Traffic flow is determined by the joint consideration of the temporal evolution of volume and occupancy. The boundary conditions of the different regimes are identified via a fuzzy wavelet approach based on the volume-occupancy relationship. Moreover, a Bayesian network is developed in order to discover hidden associations between the observed shifts and the traffic flow conditions they occur. Results from the data-driven approach indicate the existence of four distinct traffic flow regimes; these regimes hold in arterials with different geometric and signalization characteristics. Finally, results are further discussed via an analytical model based on the kinematic wave theory; the comparative study of both approaches provides strong evidence that the presented statistical framework is in agreement with a simple and elegant analysis including traffic parameters that are observable and measurable.

This paper presents an investigation conducted to identify obstacles that prevent sufficient consideration of future road maintenance needs during the road planning and design phase. The investigation focuses on the road planning and design process within the Swedish Road Administration. For this reason the results are applicable for Nordic conditions concerning road design, maintenance, and climate. However, the results focus on general aspects of the planning and design process and ought to also be valid for other conditions outside the Nordic countries. The investigation was carried out using a method called “change analysis,” which consists of complementary steps for the analysis of problems, processes, and goals in order to identify necessary changes. The investigation identified several problems within the road planning and design process related to consulting, knowledge, planning and design activities, regulations, organization structure, and demands from other authorities. The identified problems, activities within the planning and design process, and goals for the process were analyzed. Based on these analyses the investigation identifies the most urgent needs for change in order to eliminate the problems that result in insufficient consideration of maintainability during the planning and design process.

Various factors are provided in the Highway Capacity Manual to adjust the base saturation flow rate for the capacity analysis of signalized intersections under the prevailing conditions. There are, however, no factors to account for the possible change of capacity at signalized intersections caused by professional taxi drivers in the traffic stream. The results obtained from a study to develop professional driver adjustment factors for capacity analysis of signalized intersections are summarized. The factors were derived on the basis of the data collected in Yokohama City, Japan. The results indicated that taxi drivers had a significant impact on the saturation flow rate. When a signalized intersection was identified with a high volume of taxi drivers, the saturation flow rate as well as the capacity could be increased by 20%, which corresponded to a professional driver adjustment factor as high as 1.20.