Incorporating spatial characteristics in travel demand models

The goal of this study was to address one of the major weaknesses of the ubiquitous four-step procedure for travel demand modeling: omission of spatial interactions between the variables. While contiguity of the analysis zones is commonly used to define spatial interaction of the variables in spatial analysis, it might not capture the interactions of travel demand variables. In this study, the efficacies of four alternative methods for defining spatial relationships: contiguity, separation, a combination of contiguity and separation, and economic linkages (accessibility), were evaluated. The home-based-work (HBW) spatial models and non-spatial models for trip attraction, and trip production were developed. For the destination choice, the spatial models were developed by using separation and accessibility alternatives for defining spatial relationship. Comparison of the trip attraction models indicated that the model estimated using the separation spatial relationship had the best fit. Furthermore, comparison of the best spatial model and the non spatial model indicated that the spatial model outperforms the non spatial model by increasing the prediction accuracy by 14%. For the trip production model, the results indicated that the spatial variable is unnecessary. For destination choice, the spatial model developed using separation spatial relationship was found to he the best based on statistical tests. To compare the spatial model and the non-spatial model, the forecasted alternative destination shares were used. The results indicated that the difference between the forecasted alternative shares by using spatial and non-spatial models is small when there is a small percentage increase in casino/hotel and retail jobs. In order to use the developed destination choice models for long-term forecasting, additional variables such as housing location should be included. Also, since the design of the analysis zones used in this study may not be optimal, an attempt to design new analysis zones through a careful aggregation process in which homogeneity is carefully controlled, is recommended

18-01 Sustainable and Smart-growth City Ranking: Multifaceted Transportation Performance Measures in Smart Cities

The concept of smart city is fast becoming a key instrument in transforming living environments in a way better to enhance operational efficiency of a transportation system. This study identifies a framework to assess transportation performance measures and smart-growth of cities around the U.S. The proposed assessment framework is comprised of the evaluation of individual criterion and the assessment of comprehensive results. The criteria are categorized into four groups including network performance, traffic safety, environmental impact, and physical activity. This study provides a multifaceted approach to integrate the criteria’s performance measures. As a case example, the proposed performance measures were examined for forty-six cities in the U.S. and the required data were gathered from multiple sources. A multi-criteria decision analysis (MCDA) method was employed to integrate and evaluate the score associated with each city. The output of the framework contains a sustainable and smart-growth ranking of the selected cities as well as uncertainty and sensitivity analysis. The sensitivity analysis was utilized to determine the quantity that each performance measure or weighting factor requires to alter the smart-growth score. It has been illustrated that the dominancy between reversible pairs in the ranking are critically sensitive for almost 15% of cases. The results of the proposed framework can be an effective decision supporting tool in analyzing traffic management strategies. Results from the score sensitivity calculation indicate that the proposed framework can be adopted in multifaceted transportation system performance in sustainable and smart-growth of cities

16-04 Effectiveness of Bicycle Signals for Improving Safety and Multimodal Mobility at Urban Intersections

With the dramatic increase of non-motorized transportation users, more people are concerned about the non-motorized traffic safety. Unfortunately, bicyclists and pedestrians are prone to more severe injuries when involved in a crash. For bicycle crashes, failing to yield/disregarding traffic control device, and lack of non-motorized facilities were identified to be the main causes of bicycle crashes in urban intersections. This research investigated the effectiveness of two bicycle crash countermeasures with bicycle signal treatments at urban signalized intersections. These two countermeasures are the bike boxes and the protected intersections. The bicycle signal treatments that were tested simultaneously with these countermeasures are the leading bicycle interval and the exclusive bicycle phase. A before and after bicyclist survey was conducted to measure bicyclist perception of safety of the bike box and bicycle signal heads. Additionally, these engineering countermeasures were evaluated from both traffic operation and traffic safety prospective in a virtual test environment built in VISSIM. Users delay were compared before and after implementing these countermeasures. While a surrogate safety measure “conflicts” among users was used to measure the safety impact of such treatments. Through performing benefit-cost analysis, the threshold values of traffic and bike volumes that are needed to justify the bike box and the protected intersection treatments were found. This research also provided a general guideline that can be used by the decision makers to facilitate bicyclist left turn movement at urban signalized intersections

18-02 Investigating and Prioritizing Factors for Quantifying Bikeability

Bikeability is an important element that must be considered in planning bicycle facilities. The resource constraints make it imperative for the planners and engineers to be able to identify and shortlist important factors that promote cyclists’ friendly environment. The current study utilized the Analytical Hierarchy Process (AHP), a multiple criteria decision analysis technique, to rank the relative importance of bikeability factors for on-road bicycle facilities. AHP is the most applied multiple criteria decision analysis technique due to its ability to convert subjective judgment to a numerical value which can easily be incorporated in the decision-making process. A survey was administered to experienced cyclists and experts (i.e. planners and engineers), who were asked to rank the relative importance of one factor over the other when assessing the bikeability of on-road designated bike lanes, shared lanes, off-road bicycle facilities, intersections and bicycle infrastructure network. While this report documents summary results for other facilities studies, it gives detailed analysis results for on-road designated bike lanes since they had sufficient responses from the survey. Out of 21 factors that were investigated, the presence and enforcement of passing distance laws was ranked as the most important factor to consider when assessing the bikeability of on-road bicycle facilities. Other important factors, in descending order of importance, were bike lane marking, presence of on-street parking, bike lane type, presence of roadside hazards, motor vehicle speed, presence of paved shoulders and motor vehicle volume, among others. The results from this research form a basis for the factors deemed important by cyclists, planners and designers when assessing the bikeability of on-road bicycle lanes

16-06 Vehicle-to-Device (V2D) Communications: Readiness of the Technology and Potential Applications for People with Disability

IEEE 802.11p was developed as an amendment to IEEE 802.11 for wireless access in vehicular environments (WAVE). While WAVE is considered the de facto standard for V2V communications, in the past few years a number of communications technologies have emerged that enable direct device-to-device (D2D) communications. Technologies like Bluetooth Smart, WiFi-Direct and LTE-Direct allow devices to communicate directly without having to rely on existing communications infrastructure (e.g., base stations). More importantly, these technologies are quickly penetrating the smartphones market. The goal of this research is to conduct extensive simulation and experimental studies to assess the efficacies of utilizing D2D communications technologies in transportation scenarios focused around pedestrians and bicyclists. Specifically, we design, develop, and experiment with Smart Cone and Smart Cane systems to evaluate the readiness of D2D technologies to support transportation applications

14-03 Transportation System and Its Association with Human Health - A Review and Modeling Approach

Transportation systems constitute of infrastructure, commute modes, land use and other policies. The purpose of transportation is to provide easy access to goods and services. While attaining this purpose, impacts of transportation on human health and well-being have been ignored to some extent. Recently, studies have begun analyzing the impact of transportation systems on quality of life and health disparities. While many studies have discussed the impact of the transportation system on individual factors from health, a very limited number of studies have focused on the impact of multiple factors associated with multiple morbidity and mortality forms. The focus of this study is to analyze how transportation infrastructure can promote physical activities resulting in better health outcomes. Lack of data on transportation infrastructure at county-level in Michigan restricted the study. The Transportation and Health Tool developed by the US Department of Transportation was reviewed and applied to Michigan at a county-level to examine how different counties rank with respect to different transportation indicators corresponding to health conditions. Further, correlation analyses and multinomial linear regression analyses were conducted to determine relationships and impact magnitudes of transportation and socioeconomic factors on human health

14-05 Development of Decision Support Tools to Assess Pedestrian and Bicycle Safety: Development of Safety Performance Functions

While a number of studies have developed Safety Performance Functions (SPFs) for motorized traffic, there has been a very limited focus on developing SPFs for non-motorized traffic. Lack of exposure measures for pedestrians and bicyclists has been cited often as the obstacle to developing reliable SPFs. This project aimed at developing statewide SPFs for bicyclists and pedestrians at urban intersections. The SPFs developed can be used as a decision supporting tool for planners and practitioners in prioritizing areas for safety improvements. In order to capture crash patterns despite, a carefully designed sampling approach was implemented and improvements on other aspects of modeling were made. Specifically, we implemented structural equation modeling in the efforts to establish proxy measures of non-motorized exposures. SPFs for pedestrians and bicyclists at urban intersections, are recommended

17-05 Effects of Safe Bicycle Passing Laws on Drivers\u27 Behavior and Bicyclists\u27 Safety

This report identifies the effect of passing distance laws on drivers’ behaviors and bicyclist’s safety during an overtaking maneuver. Using an instrumented bicycle and driver survey, the study measured bicycle passing in a naturalistic field experiment using video recording, an ultrasonic distance measuring device, and a LiDAR. In order to evaluate the effect of passing distance laws, the study examined jurisdictions with a three-foot passing law, with a five-foot passing law, and without a passing law. The experiment required a bicyclist to ride the instrumented bicycle in two-lane and three-lane roads to capture the distance between the bicycle and the overtaking motor vehicle. Moreover, a new analysis algorithm is presented to assess the speed and distance transformation of the vehicles approaching and entering the passing zone of the bicycle in micro level transportation systems. The results demonstrated that drivers’ overtaking distances were significantly greater in locations with the five-foot passing law than in other areas. The study also found that roads with paved shoulders, wider travel lanes, and a greater number of lanes were associated with greater passing distances. In contrast, we found that passing distance was shorter on roads with shared lane markings (i.e., sharrows) or higher truck composition. By comparing the surveys conducted in locations with different passing laws, the study illustrates that drivers usually overestimate the distance that they pass bicyclists. These results can be useful to transportation engineers, policymakers, and legislators who intend to provide efficient designs of road infrastructure to better accommodate bicycles